MD Nastran 2010 EFEA User Guide

110
MD Nastran R2.1 Installation and Operations Guide MSC.Software EFEA 2010 User’s Guide

description

The Energy Finite Element Analysis (EFEA) and Energy Boundary Element Analysis (EBEA) provides a powerful solution for high frequency acoustics. In contrast to traditional FEA solvers that use displacements as the primary variables, the EFEA methods use energy based variables which enables noise and vibration simulations at much higher frequencies than those attained by conventional FEA analysis. The EBEA solution provides airborne noise loads for use by the EFEA solution. The combination of EBEA and EFEA methods can be used to predict the interior noise levels in a vehicle due to exterior acoustic sources.

Transcript of MD Nastran 2010 EFEA User Guide

Page 1: MD Nastran 2010 EFEA User Guide

MD Nastran R2.1 Installation and Operations Guide

MSC.Software

EFEA 2010 User’s Guide

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Corporate Europe Asia Pacific

MSC.Software Corporation 2 MacArthur Place Santa Ana, CA 92707 Telephone: (800) 345-2078 FAX: (714) 784-4056

MSC.Software GmbH Am Moosfeld 13 81829 Munich GERMANY Telephone: (49) (89) 43 19 87 0 Fax: (49) (89) 43 61 71 6

Asia Pacific MSC.Software Japan Ltd. Shinjuku First West 8F 23-7 Nishi Shinjuku 1-Chome, Shinjuku-Ku Tokyo 160-0023, JAPAN Telephone: 0120-924-832 (toll free, Japan only) Mobile phone: 03-6911-1222 Fax: (81) (3)-6911-1201

Worldwide Web www.mscsoftware.com

Disclaimer MSC.Software Corporation reserves the right to make changes in specifications and other information contained in this document without prior notice. The concepts, methods, and examples presented in this text are for illustrative and educational purposes only, and are not intended to be exhaustive or to apply to any particular engineering problem or design. MSC.Software Corporation assumes no liability or responsibility to any person or company for direct or indirect damages resulting from the use of any information contained herein. User Documentation: Copyright © 2010 MSC.Software Corporation and its licensors. Portions of this document are licensed from Michigan Engineering Services LLC. Printed in U.S.A. All Rights Reserved. This notice shall be marked on any reproduction of this documentation, in whole or in part. Any reproduction or distribution of this document, in whole or in part, without the prior written consent of MSC.Software Corporation is prohibited. This software may contain certain third-party software that is protected by copyright and licensed from MSC.Software suppliers. MSC, MD, Dytran, Marc, MSC Nastran, MD Nastran, MSC Patran, MD Patran, OpenFSI, the MSC.Software corporate logo, and Simulating Reality are trademarks or registered trademarks of the MSC.Software Corporation in the United States and/or other countries. NASTRAN is a registered trademark of NASA. PAMCRASH is a trademark or registered trademark of ESI Group. SAMCEF is a trademark or registered trademark of Samtech SA. LS-DYNA is a trademark or registered trademark of Livermore Software Technology Corporation. ANSYS is a registered trademark of SAS IP, Inc., a wholly owned subsidiary of ANSYS Inc. ABAQUS is a registered trademark of ABAQUS Inc. All other brand names, product names or trademarks belong to their respective owners. PCGLSS 6.0, Copyright © 1992-2005, Computational Applications and System Integration Inc. All rights reserved. PCGLSS 6.0 is licensed from Computational Applications and System Integration Inc. METIS is copyrighted by the regents of the University of Minnesota. A copy of the METIS product documentation is included with this installation. Please see "A Fast and High Quality Multilevel Scheme for Partitioning Irregular Graphs". George Karypis and Vipin Kumar. SIAM Journal on Scientific Computing, Vol. 20, No. 1, pp. 359-392, 1999.

Revision 0. July 9, 2010

MDNA:V2010:Z:Z:Z:DC-EFEA

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I. Introduction

The Energy Finite Element Analysis (EFEA) and Energy Boundary Element Analysis

(EBEA) provides a powerful solution for high frequency acoustics. In contrast to

traditional FEA solvers that use displacements as the primary variables, the EFEA

methods use energy based variables which enables noise and vibration simulations at

much higher frequencies than those attained by conventional FEA analysis. The EBEA

solution provides airborne noise loads for use by the EFEA solution. The combination of

EBEA and EFEA methods can be used to predict the interior noise levels in a vehicle due

to exterior acoustic sources. These new solvers are provided through collaboration with

Michigan Engineering Services and are provided as a pre-release in MD Nastran 2010.

The EFEA (Energy Finite Element Analysis) program requires a single input data file

which contains all the required data for the analysis. The order in which the information

is contained in the data file is not important.

Solid finite elements are used for modeling interior acoustic spaces. If the model does

not contain any interior acoustic medium (i.e. only a structural vibration analysis is

performed), then Sections 3 – 5 do not exist in the data file. A Pre-EFEA code is utilized

for generating the EFEA input data file from the finite element model. The following

procedure must be followed when generating the EFEA input data file.

Step 1 – Create the conventional FEA model using a pre-processing software. Use a

general purpose pre-processor for creating the finite element model. The

model is created just like a conventional finite element model is created, but

without considering the rule of having 6 linear elements per wavelength. The

size of each element can be large, as long as the model captures the main

geometric characteristics of the physical system it models. A single model

must contain all structural and acoustic elements. Each structural node and

element, and each acoustic node and element must have a unique ID number.

Different material properties should be indicated through a different property

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ID number. The entire finite element model needs to be exported from the pre-

processor in NASTRAN short fixed format.

Step 2 – Run the Pre-EFEA code on the conventional FEA model. The finite element

model constructed using a pre-processor comprises the main input for the Pre-

EFEA code. The pre-EFEA code detects all geometric features, changes in

material properties, intersections between components, interfaces between

structural and acoustic elements, and automatically performs the following

actions:

• disconnects the model at each joint location by adding appropriate nodes

and by updating the connectivity of the elements

• creates all the necessary joints among structural elements or between

structural and acoustic elements

• creates the EFEA input data file which contains all the nodes and elements

for the structural and acoustic parts of the model (with modified node

numbers and accordingly updated element connectivity at the joints), and

all the necessary cards which define the joint connections

The Pre-EFEA code automates a very tedious process and creates the majority of the data

file for the EFEA analysis.

Step 3 – Modify the EFEA model file generated by the Pre-EFEA code. The user must

edit the EFEA input data file created from the Pre-EFEA code in order to

provide information about:

• the excitation (input power, location, and frequency)

• material properties (for the structural components and for each acoustic

domain)

• geometry information for the radiation efficiency computations

• acoustic absorption properties for representing acoustic treatment

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• the solver option

• the format of the requested output

If the substructuring option is NOT utilized then NO further step is required before

executing the EFEA solver. If the substructuring option is selected, then the user must

use the pre-processor and divide the original finite element model into substructures. It is

advisable to define the substructures in a manner that minimizes the interface between

substructures. Separating the entire finite element model (both structural and acoustic

elements) into groups of elements constitutes the definition of the substructures. Each

group can contain both structural and acoustic elements and dividing the model into

groups of elements (i.e. substructures) strictly depends on the geometry. The user needs

to output each group of elements (i.e. substructure) into a separate file. Typically, this is

feasible by making one group at a time active within the pre-processor and then writing

out the active group. Each file generated from this process constitutes one of the

“sub*.elem” files. “*” is the substructure number starting from 1 and increasing

sequentially. It does not matter if the nodes retain the old numbering scheme in the

“sub*.elem” files. The information which is utilized by the solver for defining each

substructure is the element numbers only. One important check is to ensure that the total

number of elements in all the “sub*.elem” files is equal with the total number of elements

in the EFEA input data file.

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II. Running EFEA code

The syntax for running the EFEA code is:

EFEA inputfile outputfile

In this syntax, inputfile is a user defined input data file name, which contains all the

required data for the EFEA analysis; outputfile is the user specified output file name,

EFEA will output all results in this specified file.

Lengths of both inpufile and outputfile should be less than 80 characters.

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III. Input format for the data file for the EFEA analysis

This section of the User’s Manual describes all possible entries in the EFEA input data file. For

all entries defined in NASTRAN format (i.e. GRID, CQUAD4, CTRIA3, CBAR, CHEXA,

CPENTA, CTETRA, CBUSH, CFAST, CWELD, CWSEAM, PBUSH, PFAST, PWELD,

PWSEAM) the NASTRAN fixed short format must be used. For all other entries a free format

can be used with at least one empty space used as a separator between fields. The length of any

input entry must not exceed 80 characters. The function and the required input format for all

available cards are defined in the following sections (the sequence of defining any one of the

entries in the data file is not important). In the most general case there are five distinct sections

of information in the data file:

Section 1 – Contains information about the excitation, the physical material properties, the

solution options, and the required format of the results.

Section 2 – Contains the nodes and the elements for the entire structural model in NASTRAN

short fixed format. This Section also contains information about all the joints

defined among structural elements.

Section 3 – Contains the nodes and the elements for the entire acoustic model in NASTRAN

short fixed format.

Section 4 – Contains all the joint definitions between acoustic elements and structural elements.

Section 5 – Contains information about the acoustic absorption boundary conditions.

All functions are listed alphabetically in each section.

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Section 1:

Includes information about the excitation frequencies, the type and location of the excitations,

the physical material properties of all the elements (structural and acoustic), the requested solver,

and the format of the required output.

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ACOUS Input power in acoustic

Specify the frequency-dependent acoustic input power at a particular acoustic node. The

amplitude of the input power at a frequency is equal to the scale factor q times the value in table

qtb at the corresponding frequency. This entry must be located in a load case defined by a pair of

SUBCASE and ENDSUBCASE entries.

Format:

ACOUS nid q qtb

Example:

ACOUS 100 90.0 1

Note:

nid The ID number of the node where the input power is prescribed. [integer]

q Scale factor. [Real]

qtb ID number of the DTABLE entry.

Remarks:

The acoustic input power from an acoustic source with the strength of V can be calculated by

πckV

800

22 ρ

where 0ρ is the density of acoustic medium, 0c is the speed of sound in the acoustic medium, k

is the wave number in the acoustic medium.

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ASOURCE Acoustic source in fluid

Specify the frequency-dependent acoustic source at a particular acoustic node. The amplitude of

the source at a frequency is equal to the scale factor s times the value in table stb at the

corresponding frequency. This entry must be located in a load case defined by a pair of

SUBCASE and ENDSUBCASE entries.

Format:

ASOURCE nid s stb

Example:

ASOURCE 100 90.0 1

Note:

nid The ID number of the node where the input power is prescribed. [integer]

s Scale factor. [Real]

stb ID number of the DTABLE entry.

Remarks:

The acoustic source strength is defined as the volume velocity amplitude V of the acoustic

source. The acoustic input power from this acoustic source can be calculated by

πckV

800

22 ρ

where 0ρ is the density of acoustic medium, 0c is the speed of sound in the acoustic medium, k

is the wave number in the acoustic medium.

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CHECK Set flag for model check-up

Set the flags to activate model integrity check-up.

Format:

CHECK field1 field2 …

Example:

CHECK CQUAD4

Note:

fieldi =CQUAD4 Activate the check-up of CQUAD4 element for bow-tie shape.

Remarks:

Currently the check-up is only available for bow-tie shape CQUAD4 elements.

When any bow-tie shape CQUAD element is detected, the EFEA code will issue an error

message and stop.

In the future, more fieldi may be available for other check-ups.

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BARRIER Input mass barrier

Specify the mass barrier added on the base panels (e.g. mass barriers on the vehicle floors or

dashes).

Format:

BARRIER pid mb

Example:

BARRIER 1 2.5

Note:

pid Refers to the ID number of PLATE entry, on which the mass barrier is added.

mb Surface mass density of the mass barrier. [Real]

Remarks:

When the mass barrier is added on the base panels (e.g. mass barriers on the vehicle floors or dashes), their influence on the acoustic performance of the base panels can be expressed by the modified mass law transmission effect. Usually, these barriers are assumed weakly reactive and thus not affecting the dynamics of the base panel. The modified normal mass law transmission coefficient from acoustic enclosure 1 to acoustic enclosure 3 through a panel with mass barrier applied can be written as

++

+

= 2

33

2

33

1133

11

1

4

cmt

ccc

c

Bss

normal

ρρω

ρρρ

ρτ

where Bm is the surface mass density of the mass barrier. Similarly, equations (13) and (14) can be used to calculate the corresponding field mass law transmission coefficient.

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CMAT2 Plate material anisotropic property definition

Define a frequency dependent anisotropic material property data set for plate elements.

Format:

CMAT id G11 G12 G13 G22 G23 G33 ρ ηb ηl ηs tb1 tb2 tb3

Example:

CMAT2 1 1.0E11 1.7E10 2.7E10 1.6E10 1.0E10 2.1E10 2791.5 0.01 0.01 0.01 1 1 1

Note:

id A unique material ID associated with the data set. [Integer]

Gij The material property matrix. [Real]

ρ Mass density. [Real]

ηb Scale factor for defining the frequency-dependent damping loss factor for the bending

wave. The value of the damping loss factor at a frequency is equal to the scale factor ηb

times the value in table tb1 at the corresponding frequency.

ηl Scale factor for defining the frequency-dependent damping loss factor for the

longitudinal wave. The value of the damping loss factor at a frequency is equal to the

scale factor ηl times the value in table tb2 at the corresponding frequency.

ηs Scale factor for defining the frequency-dependent damping loss factor for the shear wave.

The value of the damping loss factor at a frequency is equal to the scale factor ηs times

the value in table tb3 at the corresponding frequency.

tbi ID number of the DTABLE entry.

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CPLATE Anisotropic plate element property definition

Specify the frequency-dependent physical property (transmission loss) data set for anisotropic

plate elements.

Format:

CPLATE id t mid1 mid2 ns L1 L2 e1 fmid1 e2 fmid2 yj zj w*(yj,zj) tl1 tl2 tltb1 tltb2

Example:

CPLATE 1 0.001 2 3 1 0.19 0.47 0.0 1 0.0 0 0.0 0.0 0.0 0.22 0.22 1 1

Note:

id A unique ID number associated with the data set. [Integer]

t The thickness of the plate. [Real]

mid1 The CMAT2 ID number for in-plane material properties of the plate.[Integer]

mid2 The CMAT2 ID number for bending material properties of the plate.[Integer]

ns Number of plate sides contacted with exterior free-field fluid. [Integer]

L1,L2 The characteristic dimensions of the plate (length and width, respectively).[Real]

e1 The acoustic radiation efficiency of the plate. If the value is set to zero, the program will

compute the acoustic radiation efficiency for the plate.[Real]

fmid1 The material ID of exterior fluid contacts with plate at one side.[integer]

e2 The acoustic radiation efficiency of the plate (only necessary when ns is set to 2). If the

value is set to zero, the program will compute the acoustic radiation efficiency for the

plate.[Real]

fmid2 The material ID of exterior fluid contacts with plate at another side(only necessary when

ns is set to 2).[integer]

yj , zj The coordinates of the edge of plate which connect to a stiffener. (The origin of the

coordinate is the shear center of the stiffener) [Real]

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w*(yj,zj)The warping coefficient of a stiffener. [Real]

tl1 Scale factor for defining the user-specified frequency-dependent transmission loss factor

(dB) from acoustic medium 1 to acoustic medium 2. The value of this transmission loss

factor at a frequency is equal to the scale factor tl1 times the value in table tltb1 at the

corresponding frequency.

tl2 Scale factor for defining the user-specified frequency-dependent transmission loss factor

(dB) from acoustic medium 2 to acoustic medium 1. The value of this transmission loss

factor at a frequency is equal to the scale factor tl2 times the value in table tltb2 at the

corresponding frequency.

tltb1 ID number of the DTABLE entry.

tltb2 ID number of the DTABLE entry.

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DTABLE Table constants

Defines a table with a set of values vi which are related to the frequencies listed in FREQ

entries. The number of vi in a DTABLE entry should be equal to the total number of frequencies

defined in all FREQ entries and in the same sequence. This entry can be used to define the

frequency-dependent parameters (i.e. frequency-dependent excitations, frequency-dependent

material properties).

Format:

DTABLE ID v1 v2 … vn

Example:

DTABLE 1 1.0 2.0 3.0 4.0

Note:

ID The ID number of a table. [Integer]

vi The corresponding value at different frequencies.

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EDACS Acoustic energy density constraint

Specify the frequency-dependent acoustic energy density at a particular acoustic node. The value

of the energy density at a frequency is equal to the scale factor e times the value in table etb at

the corresponding frequency. This entry must be located in a load case defined by a pair of

SUBCASE and ENDSUBCASE entries.

Format:

EDACS nid e etb

Example:

EDACS 100 90.0 1

Note:

nid The ID number of the node where the energy density is prescribed. [integer]

e Scale factor. [Real]

etb ID number of the DTABLE entry.

Remarks:

The acoustic energy density Ae~ can be calculated by

+= 2

00

22

041~

cpueA ρ

ρ

where 0ρ is the density of acoustic medium, 0c is the speed of sound in the acoustic medium, u

is the acoustic particle velocity, p is the acoustic pressure.

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EDPLTB Bending energy density constraint at plate node

Specify the frequency-dependent bending energy density at a particular structural node. The

value of the energy density at a frequency is equal to the scale factor e times the value in table

etb at the corresponding frequency. This entry must be located in a load case defined by a pair of

SUBCASE and ENDSUBCASE entries.

Format:

EDPLTB nid e etb

Example:

EDPLTB 100 90.0 1

Note:

nid The ID number of the node where the energy density is prescribed. [integer]

e Scale factor. [Real]

etb ID number of the DTABLE entry.

Remarks:

The bending energy density Be~ of plate can be calculated by

2~ we sB ρ=

where sρ is the material density of plate, 2w is the mean square normal velocity of plate.

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EDPLTIP Longitudinal energy density constraint at plate node

Specify the frequency-dependent longitudinal energy density at a particular structural node. The

value of the energy density at a frequency is equal to the scale factor e times the value in table

etb at the corresponding frequency. This entry must be located in a load case defined by a pair of

SUBCASE and ENDSUBCASE entries.

Format:

EDPLTIP nid e etb

Example:

EDPLTIP 100 90.0 1

Note:

nid The ID number of the node where the energy density is prescribed. [integer]

e Scale factor. [Real]

etb ID number of the DTABLE entry.

Remarks:

The longitudinal energy density Le~ of plate can be calculated by

2~LsL ue ρ=

where sρ is the material density of plate, 2Lu is the mean square in-plane velocity of plate

corresponding to the dilational motion of plate.

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EDPLTSH In-plane shear energy density constraint at plate node

Specify the frequency-dependent shear energy density at a particular structural node. The value

of the energy density at a frequency is equal to the scale factor e times the value in table etb at

the corresponding frequency. This entry must be located in a load case defined by a pair of

SUBCASE and ENDSUBCASE entries.

Format:

EDPLTSH nid e etb

Example:

EDPLTSH 100 90.0 1

Note:

nid The ID number of the node where the energy density is prescribed. [integer]

e Scale factor. [Real]

etb ID number of the DTABLE entry.

Remarks:

The in-plane shear energy density Se~ of plate can be calculated by

2~SsS ue ρ=

where sρ is the material density of plate, 2Su is the mean square in-plane velocity of plate

corresponding to the rotational motion of plate.

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EFEA_PS Periodic stiffener property definition

Defines the properties of a periodically stiffened cylinder or flat plate (for the stiffened cylinder

case, the stiffener is simulated as a physical property in the EFEA model, this stiffener is not an

independent element; for the stiffened flat plate case, the stiffener is simulated by plate elements

in EFEA model), the transmission coefficient through the periodic stiffeners is calculated based

on the PS theory method.

Format:

EFEA_PS PSID PSSTYLE RID PID LENGTH WIDTH RADIUS OFFSET1 OFFSET2 EMU

Example:

EFEA_PS 1 1 2 2 0.3607 0.1596 0.6096 1.34E-3 1.59E-2

Note:

PSID A unique ID number associated with the data set.

PSID refers to #rpid in PJOINT entry.

PSSTYLE Periodic stiffener type.

=1 Ring periodic stiffeners attached to a cylinder

=2 Axial periodic stiffeners attached to a cylinder

=3 Period stiffeners (simulated as plate elements) attached to a flat plate

RID If PSSTYLE=1 or 2, RID refers to the ID number of RIB entry, which defines

the geometry properties of the periodic stiffener.

If PSSTYLE=3, RID refers to the ID number of PLATE entry, which defines the

geometry properties of the plate which acts as the periodic stiffener attached to a

flat plate.

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PID Refers to the ID number of PLATE entry, which defines properties of the

cylinder (when PSSTYLE=1 or 2) or flat plate (when PSSTYLE=3) attached by

the periodic stiffeners.

LENGTH &

WIDTH Geometry sizes of the bay of the cylinder (or flat plate) between adjacent periodic

stiffeners.

For periodic ring stiffeners:

LENGTH is the distance along the cylinder generator between two ring stiffeners

(Figure 1-3).

WIDTH is the size of plate element along the circumference of the cylinder used

in EFEA model.

For periodic stiffeners in the axial direction:

LENGTH is the length of axial stiffener along the cylinder generator (Figure 1-

4).

WIDTH is the distance along the cylinder circumference between two axial

stiffeners (Figure 1-4).

For periodic stiffener attached to the flat plate case:

LENGTH is the length of stiffener (Figure 1-5).

WIDTH is the distance between two adjacent stiffeners (Figure 1-5).

RADIUS The radius of the cylinder attached by the periodic stiffeners.

=9999 For periodic stiffeners attached to the flat plate case.

OFFSET1 &

OFFSET2 Offsets of the stiffener center to the attached cylinder or flat plate surface.

OFFSET1 the default value is equal to 0 (it has to be equal to zero if the stiffener

is symmetric)

OFFSET2 is the distance from the center of stiffener to the attached cylinder or

flat plate surface.

EMU Specifies for a user defined propagation constant for periodically stiffened

cylinder. If blank (recommended), the propagation constant will be calculated by

codes based on PS theory.

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Remarks:

• For type 1 where periodic ring stiffeners attach to a cylinder, geometric parameters

LENGTH and RADIUS are used in the periodic theory to calculate the propagation

constant of wave. While the parameter WIDTH is only used for iteration purpose

internally in the EFEA code, which is equal to the size of plate element along the

circumference of cylinder used in the EFEA model.

• For type 2 where periodic axial stiffeners attach to a cylinder, geometric parameters

LENGTH, WIDTH and RADIUS are used in the periodic theory to calculate the

propagation constant of wave.

• For type 3 where periodic stiffeners attach to a flat plate, geometric parameters

LENGTH and WIDTH are used in the periodic theory to calculate the propagation

constant of wave.

Fig 1-3 Type 1 Fig 1-4 Type 2 Fig 1-5 Type 3

Length Length

Width

Length

Width

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ENDSUBCASE Subcase delimiter

Delimit and identify the end of a load case, must be paired with SUBCASE entry.

Format:

ENDSUBCASE

Example:

ENDUBCASE

Note:

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FREQ Frequency list

Define a set of frequencies for EFEA analysis. The central frequencies of 1/3 octave frequency

band should be used. Multiple frequencies can be specified on one line as far as the total length

of the line does not exceed 80 characters. Repeated lines of FREQ can be used to specify more

frequencies.

Format:

FREQ f1 f2 f3 …

Example:

FREQ 100.0 125.0 160.0

Note:

fi Frequency value in units of cycles per unit time. [Real]

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ISO Isolator property definition

Specify a physical property data set for isolators.

Format:

ISO pid mid A R Iy Iz J St

Example:

ISO 1 1 0.126 0.2 1.423E-7 1.423E-7 2.53E-10 2.53E-10

Note:

pid A unique ID number associated with the data set. [integer]

mid The corresponding MISO ID number of the isolator.[integer]

A The cross section area of the isolator [Real]

R The cross section equivalent radius of the isolator [Real]

Iy,Iz The bending moment of inertia of the isolator.[Reals]

J The torsion constant of the isolator [Real]

St The warp torsion constant of the isolator [Real]

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LGOPENING Leakage property definition

Define the acoustic leakage properties on a plate that separates two acoustic spaces.

Format:

LGOPENING lgid length (or radius) width (or radius) parea

Example:

LGOPENING 1 0.005 0.004 1.0

Note:

lgid The ID number of an opening [integer]

length (or radius) Length (L) of rectangular or radius (R) of circular opening

width (or radius) Width (W) of rectangular or radius (R) of circular opening.

parea The area of the plate on which the opening is located [real]

Remarks:

LGOPENING is used to model the leaking or flanking path through the panel when it connects

to two acoustic spaces on both sides. Two types of opening shapes are available in EFEA. One is

rectangular opening (Figure 1-1), the length (L) and width (W) of opening need to be defined for

this type. The other is circular opening (Figure 1-2), the radius (R) of opening needs to be

defined for this type.

Figure 1-1 Rectangular opening Figure 1-2 Circular opening

L

W R

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MAT1 Isotropic Material Property Definition

Defines the material properties for linear isotropic materials.

Format:

MAT1 MID E G NU RHO A TREF GE

ST SC SS MCSID

Note:

MID Material identification number. [Integer]

E Youn g’s modulus. [Real]

G Shear modulus. [Real]

NU Poisson’s ratio. [Real]

RHO Mass density. [Real]

A Thermal expansion coefficient. [Real]

TREF Reference temperature for the calculation of thermal loads, or a temperature-

dependent thermal expansion coefficient. [Real]

GE Structural element damping coefficient. [Real]

ST, SC, SS Stress limits for tension, compression, and shear are optionally supplied, used

only to compute margins of safety in certain elements; and have no effect on the

computational procedures. [Real]

MCSID Material coordinate system identification number. Used only for PARAM,CURV

processing. [Integer]

Remarks:

The format of MAT1 card in EFEA is exactly the same as in Nastran. Please refer to Nastran

Quick Reference Guide for more detail.

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MAT9 Anisotropic material definition

Define the properties of an anisotropic material.

Format:

MAT9 mid G11 G12 G13 G14 G15 G16 G22

G23 G24 G25 G26 G33 G34 G35 G36

G44 G45 G46 G55 G56 G66 ρ ηb

ηl ηs tb1 tb2 tb3

Example:

MAT9 103 3.842e10 2.542e9 0.0 0.0 0.0 0.0 1.02e10

0.0 0.0 0.0 0.0 1.e10 0.0 0.0 0.0

4.91e9 0.0 0.0 4.91e9 0.0 4.91e9 1.7776e3 0.03

0.02 0.01 1 1 1

Note: (Nastran fixed short format must be used, each entry occupies 8 fields)

mid Material ID

Gij Elements of the 6 X 6 material property matrix

ρ Material density

ηb Scale factor for defining the frequency-dependent damping loss factor for the bending

wave. The value of the damping loss factor at a frequency is equal to the scale factor ηb

times the value in table tb1 at the corresponding frequency.

ηl Scale factor for defining the frequency-dependent damping loss factor for the

longitudinal wave. The value of the damping loss factor at a frequency is equal to the

scale factor ηl times the value in table tb2 at the corresponding frequency.

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ηs Scale factor for defining the frequency-dependent damping loss factor for the shear wave.

The value of the damping loss factor at a frequency is equal to the scale factor ηs times

the value in table tb3 at the corresponding frequency.

tbi ID number of the DTABLE entry.

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MAT12 Orthotropic material definition

Define the properties of an orthotropic material.

Format:

MAT12 mid E11 E22 E33 U11 U22 U33 ρ

G12 G23 G31 ηb ηl ηs tb1 tb2

tb3

Example:

MAT12 102 3.778e10 1.0e10 1.0e10 0.25 0.0 0.0 1.7776e3

4.91e9 4.91e9 4.91e9 0.03 0.02 0.01 1 1

1

Note: (Nastran fixed short format must be used, each entry occupies 8 fields)

mid Material ID

Eii Elasticity modulus, (i=1,3)

Uii Posssion’s ratio, (i=1,3)

ρ Material density

Gii Shear modulus, (i=1,3)

ηb Scale factor for defining the frequency-dependent damping loss factor for the bending

wave. The value of the damping loss factor at a frequency is equal to the scale factor ηb

times the value in table tb1 at the corresponding frequency.

ηl Scale factor for defining the frequency-dependent damping loss factor for the

longitudinal wave. The value of the damping loss factor at a frequency is equal to the

scale factor ηl times the value in table tb2 at the corresponding frequency.

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ηs Scale factor for defining the frequency-dependent damping loss factor for the shear wave.

The value of the damping loss factor at a frequency is equal to the scale factor ηs times

the value in table tb3 at the corresponding frequency.

tbi ID number of the DTABLE entry.

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MBAR Beam material property definition

Define a frequency-dependent material property data set for beam elements.

Format:

MBAR mid E ρ ν ηb1 ηb2 ηl ηt tb1 tb2 tb3 tb4

Example:

MBAR 1 7.24E10 2791.5 0.33 0.01 0.01 0.01 0.01 1 1 1 1

Note:

mid A unique ID number associated with the data set. [Integer]

E Young’s modulus. [Real]

ρ The mass density. [Real]

ν Poisson’s ratio.[Real]

ηb1 Scale factor for defining the frequency-dependent damping loss factor for the bending

wave 1. The value of the damping loss factor at a frequency is equal to the scale factor

ηb1 times the value in table tb1 at the corresponding frequency.

ηb2 Scale factor for defining the frequency-dependent damping loss factor for the bending

wave 2. The value of the damping loss factor at a frequency is equal to the scale factor

ηb2 times the value in table tb2 at the corresponding frequency.

ηl Scale factor for defining the frequency-dependent damping loss factor for the longitudinal

wave. The value of the damping loss factor at a frequency is equal to the scale factor ηl

times the value in table tb3 at the corresponding frequency.

ηt Scale factor for defining the frequency-dependent damping loss factor for the torsion

wave. The value of the damping loss factor at a frequency is equal to the scale factor ηt

times the value in table tb4 at the corresponding frequency.

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tbi ID number of the DTABLE entry.

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METHOD Select solver

Select the solver for EFEA analysis.

Format:

METHOD Character

Example:

METHOD ‘D’

Note:

‘E’ (Default) Using the elimination solver

‘D’ Using the decomposition solver

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MISO Isolator material property definition

Define a material property data set for isolators.

Format:

MISO id E ρ ν

Example:

MISO 1 7.24E10 2791.5 0.33

Note:

id A unique ID number associated with the data set. [Integer]

E Young’s modulus. [Real]

ρ The mass density. [Real]

ν Poisson’s ratio. [Real]

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MPLATE Plate material property definition

Define a frequency dependent material property data set for plate elements.

Format:

MPLATE id E ρ ν ηb ηl ηs tb1 tb2 tb3

Example:

MPLATE 1 7.24E10 2791.5 0.33 0.01 0.01 0.01 1 1 1

Note:

id A unique material ID associated with the data set. [Integer]

E Young’s modulus. [Real]

ρ Mass density. [Real]

ν Poisson’s ratio. [Real]

ηb Scale factor for defining the frequency-dependent damping loss factor for the bending

wave. The value of the damping loss factor at a frequency is equal to the scale factor ηb

times the value in table tb1 at the corresponding frequency.

ηl Scale factor for defining the frequency-dependent damping loss factor for the

longitudinal wave. The value of the damping loss factor at a frequency is equal to the

scale factor ηl times the value in table tb2 at the corresponding frequency.

ηs Scale factor for defining the frequency-dependent damping loss factor for the shear wave.

The value of the damping loss factor at a frequency is equal to the scale factor ηs times

the value in table tb3 at the corresponding frequency.

tbi ID number of the DTABLE entry.

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MRIB Stiffener material property definition

Define a material property data set for stiffeners.

Format:

MRIB id E ρ ν η tb

Example:

MRIB 1 7.24E10 2791.5 0.33 0.01 1

Note:

id A unique ID number associated with the data set. [Integer]

e Young’s modulus. [Real]

ρ The mass density. [Real]

ν Poisson’s ratio. [Real]

η Scale factor for defining the frequency-dependent damping loss factor for the stiffener.

The value of the damping loss factor at a frequency is equal to the scale factor η times the

value in table tb at the corresponding frequency.

If this entry is blank, EFEA will assume there is no damping in the stiffeners.

tb ID number of the DTABLE entry.

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NOEXML Deactivate the mass law effect for JPLAC joint with exterior fluid.

Deactivate the mass law (non-resonant) path for JPLAC joint with exterior fluid (or air)

contacting on the other side of plate. By default, the mass law effect is automatically activated

for the JPLAC joint with exterior fluid/air contacting on the other side of plate.

Format:

NOEXML

Example:

NOEXML

Note:

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NOML Deactivate the mass law effect for JACPLAC joint

Deactivate the mass law (non-resonant) path for JACPLAC joint. By default, the mass law

effect is automatically activated for the JACPLAC joint.

Format:

NOML

Example:

NOML

Note:

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NSUB Substructure

Specify the number of substructures. (Note: To activate the substructuring analysis in the EFEA

solver, this entry must exist and n>1). If no substructures exist in the model, this entry is not

needed.

Format:

NSUB n

Example:

NSUB 3

Note:

n Number of substructures. [Integer]

Remarks:

There is no limitation on the number of substructures.

When n is greater than 1, the EFEA code will check the existence of files “sub1.elem”,

“sub2.elem” … “subn.elem”. If any file is missing, EEFA code will issue an error message and

stop.

When n is greater than 1, the EFEA code will also check for missing or duplicate elements. If

any missing or duplicate elements are detected, the EFEA code will issue an error message and

stop.

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OUTACS Acoustic results

Specify the components of the acoustic results outputted in the results file. The parameter fieldi

can be one or any combination of following three types.

Format:

OUTACS field1 field2 …

Example:

OUTACS E

Note:

fieldi =E Output the averaged acoustic energy density at the acoustic nodes.

=P Output the acoustic pressure (amplitude) at the acoustic nodes.

=SPL Output the sound pressure level at the acoustic nodes.

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OUTBM Beam results

Specify the components of the beam results outputted in the results file. The parameter fieldi can

be one or any combination of following five types.

Format:

OUTBM field1 field2 …

Example:

OUTBM EB1

Note:

fieldi =EB1 Output the bending 1 energy density at the beam nodes.

=EB2 Output the bending 2 energy density at the beam nodes.

=EIP Output the longitudinal energy density at the beam nodes.

=ET Output the torsion energy density at the beam nodes.

=VELO Output the transverse velocity (amplitude) at the beam nodes.

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OUTDB Using dB scale

Output the result in dB scale (usually co-exist with OUTSTR OUTCS OUTBM entries). The

parameter fieldi can be one or any combination of following three types.

Format:

OUTDB field1 field2 …

Example:

OUTDB DBS

Note:

fieldi =DBS Output the structural energy density in dB scale.

=DBA Output the acoustic energy density in dB scale.

=DBB Output the beam energy density in dB scale.

=DBSV Output the structural velocity in dB scale.

Remarks:

The dB value of structure velocity is calculated as 10.0*log10(v).

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OUTFILE Format of result file

Specify the format of the output file. The parameter formati can be one or any combination of

the following three types.

Format:

OUTFILE format1 format2 …

Example:

OUTFILE PUNCH

Note:

formati =TXT Output the results in text format with the name “outputfile.txt”

=PUNCH Output the results in NASTRAN punch format with the name of

“outputfile.pch”

=MAT Output the results in MATLAB format with name “outputfile.mat”

=PATRAN Output the results in PATRAN ‘nod’ format.

(For plate and acoustic elements only)

Multiple result files will be created, each of which corresponds to a

combination of one analyzed frequency and one subcase using

syntax of

‘s_freq=XXX_subcase=YYY.nod’ for plate elements results,

and

‘a_freq=XXX_subcase=YYY.nod’ for acoustic elements results,

where ‘XXX’ is the frequency value, and ‘YYY’ is subcase ID.

A template file “snod.res_tmpl” for plate elements, and

“anod.res_tmpl” for acoustic elements will also be created for

post-processing the results in PATRAN.

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In a ‘s_freq=XXX_subcase=YYY.nod’ file for plate results,

the first column is the bending energy density of plate,

the second column is the longitudinal energy density of plate,

the third column is the shear energy density of plate.

the fourth column is the normal velocity of plate.

In a ‘a_freq=XXX_subcase=YYY.nod’ file for acoustic results,

the first column is the acoustic energy density,

the second column is the acoustic pressure,

the third column is the SPL (sound pressure level).

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OUTSTR Plate results

Specify the components of the plate results outputted in the results file. The parameter fieldi can

be one or any combination of following four types.

Format:

OUTSTR field1 field2 …

Example:

OUTFSTR EB

Note:

fieldi =EB Output the averaged bending energy density at the plate nodes.

=EIP Output the averaged longitudinal energy density at the plate nodes.

=ESH Output the averaged shear energy density at the plate nodes.

=VELO Output the transverse velocity (amplitude) of the plate.

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PACOUS Acoustic material property definition

Define a frequency-dependent material property data set for acoustic elements, or for the exterior

free-field fluid medium.

Format:

PACOUS id ρ c η tb

Example:

PACOUS 1 1.21 343.0 0.001 1

Note:

id A unique ID number associated with the data set. [Integer]

ρ The ambient density of the acoustic medium. [Real]

c The speed of sound in the acoustic medium. [Real]

η Scale factor for defining the frequency-dependent damping loss factor for the acoustic

wave. The value of the damping loss factor at a frequency is equal to the scale factor η

times the value in table tb at the corresponding frequency.

tb ID number of the DTABLE entry.

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PBAR Beam element property definition

Specify a physical property data set for beam element.

Format:

PBAR pid mid A Iy Iz J

Example:

PBAR 1 1 2.359E-4 1.423E-7 2.156E-8 2.53E-10

Note:

pid A unique ID number associated with the data set. [integer]

mid The corresponding MBAR ID number of the beam.[integer]

A The cross section area of the beam [Real]

Iy,Iz The bending moment of inertia of the beam.[Reals]

J The torsion constant of the beam [Real]

Remarks:

PBAR data cards are translated by Pre-EFEA code from Nastran format PBAR/PBEAM/

PBARL/PBEAML data cards. If PBARL and PBEAML data cards are present in the input file of

Pre-EFEA code, Pre-EFEA code will compute A, Iy, Iz and J from the specified cross-section

types. Currently, only ‘ROD’, ‘TUBE’, and ‘BAR’ cross-section types are acceptable for

PBARL and PBEAML data cards.

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PBUSH Generalized Spring-and-Damper Property

Defines the nominal property values for a generalized spring-and-damper structural element.

Format:

PBUSH PID “K” K1 K2 K3 K4 K5 K6

“B” B1 B2 B3 B4 B5 B6

“GE” GE1 GE2 GE3 GE4 GE5 GE6

“RCV” SA ST EA ET

Note:

PID Property identification number. [Integer]

“K” Flag indicating that the next 1 to 6 fields are stiffness values in the element

coordinate system. [Character]

Ki Nominal stiffness values in directions 1 through 6. [Real]

“B” Flag indicating that the next 1 to 6 fields are force-per-velocity damping.

[Character]

Bi Nominal damping coefficients in direction 1 through 6 in units of force per unit

velocity. [Real]

“GE” Flag indicating that the next fields, 1 through 6 are structural damping constants.

[Character]

GEi Nominal structural damping constant in directions 1 through 6. [Real]

“RCV” Flag indicating that the next 1 to 4 fields are stress or strain coefficients.

(Character)

SA Stress recovery coefficient in the translational component numbers 1 through 3.

[Real]

ST Stress recovery coefficient in the rotational component numbers 4 through 6.

[Real]

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EA Strain recovery coefficient in the translational component numbers 1 through 3.

[Real]

ET Strain recovery coefficient in the rotational component numbers 4 through 6.

[Real]

Remarks:

The format of PBUSH card in EFEA is exactly the same as in Nastran. Please refer to Nastran

Quick Reference Guide for more detail.

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PCOMP N-ply composite laminate definition

Specify the properties of an n-ply composite laminate plate.

Format:

PCOMP pid N

mid_1 t_1 theta_1

mid_2 t_2 theta_2

mid_N t_N theta_N

ns L1 L2 e1 fmid1 e2 fmid2

Example:

PCOMP 1 4

1 5.0e-4 0.0

2 1.0e-2 -30.0

3 1.0e-2 30.0

4 5.0e-4 0.0

1 0.3607 0.1596 0.0 4 0.0 0

Note: (Free format can be used to define this card)

pid Property ID.

N Number of total layers

mid_i Material ID for layer i (i=1,N)

t_i Thickness for layer i (i=1,N)

theta_i Angle (degree) between the direction axis 1 of material and the

material coordinate axis x (see Fig. 1) for layer i (i=1,N)

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Figure 1 Coordinate axes x-y-z and material direction axes 1-2-3

ns Number of plate sides contacted with exterior free-field fluid

L1,L2 The characteristic dimensions of the plate (length and width, respectively)

e1 The acoustic radiation efficiency of the plate. If the value is set to zero, the program will

compute the acoustic radiation efficiency for the plate

fmid1 The material ID of exterior fluid contacts with plate at one side

e2 The acoustic radiation efficiency of the plate (only necessary when ns is set to 2). If the

value is set to zero, the program will compute the acoustic radiation efficiency for the

plate.[Real]

fmid2 The material ID of exterior fluid contacts with plate at another side(only necessary when

ns is set to 2).[integer]

2

y

3 (z )

1 x θ

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PFAST CFAST Fastener Property

Defines the CFAST fastener property values.

Format:

PFAST PID D MCID MFLAG KT1 KT2 KT3 KR1

KR2 KR3 MASS GE

Note:

PID Property identification number. [Integer]

D Diameter of the fastener. [Real]

MCID Specifies the element stiffness coordinate system. [Integer]

MFLAG Defines if the coordinate system defined by MCID is absolute or relative.[Integer]

If MFLAG = 0, MCID defines a relative coordinate system.

If MFLAG = 1, MCID defines an absolute coordinate system.

KTi Stiffness values in directions 1 through 3. [Real]

KRi Rotational stiffness values in directions 1 through 3. [Real]

MASS Lumped mass of fastener. [Real]

GE Structural damping. [Real]

Remarks:

The format of PFAST card in EFEA is exactly the same as in Nastran. Please refer to Nastran

Quick Reference Guide for more detail.

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PLATE Plate element property definition

Specify the frequency-dependent physical property (transmission loss) data set for plate

elements.

Format:

PLATE id t mid ns L1 L2 e1 fmid1 e2 fmid2 yj zj w*(yj,zj) tl1 tl2 tltb1 tltb2

Example:

PLATE 1 0.001 2 1 0.19 0.47 0.0 1 0.0 0 0.0 0.0 0.0 0.22 0.22 1 1

Note:

id A unique ID number associated with the data set. [Integer]

t The thickness of the plate. [Real]

mid The corresponding MPLATE ID number for the plate.[Integer]

ns Number of plate sides contacted with exterior free-field fluid. [Integer]

L1,L2 The characteristic dimensions of the plate (length and width, respectively).[Real]

e1 The acoustic radiation efficiency of the plate. If the value is set to zero, the program will

compute the acoustic radiation efficiency for the plate.[Real]

fmid1 The material ID of exterior fluid contacts with plate at one side.[integer]

e2 The acoustic radiation efficiency of the plate (only necessary when ns is set to 2). If the

value is set to zero, the program will compute the acoustic radiation efficiency for the

plate.[Real]

fmid2 The material ID of exterior fluid contacts with plate at another side(only necessary when

ns is set to 2).[integer]

yj , zj The coordinates of the edge of plate which connect to a stiffener. (The origin of the

coordinate is the shear center of the stiffener) [Real]

w*(yj,zj)The warping coefficient of a stiffener. [Real]

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tl1 Scale factor for defining the user-specified frequency-dependent transmission loss factor

(dB) from acoustic medium 1 to acoustic medium 2. The value of this transmission loss

factor at a frequency is equal to the scale factor tl1 times the value in table tltb1 at the

corresponding frequency.

tl2 Scale factor for defining the user-specified frequency-dependent transmission loss factor

(dB) from acoustic medium 2 to acoustic medium 1. The value of this transmission loss

factor at a frequency is equal to the scale factor tl2 times the value in table tltb2 at the

corresponding frequency.

tltb1 ID number of the DTABLE entry.

tltb2 ID number of the DTABLE entry.

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PLATEB Bending input power on plate

Specify the frequency-dependent bending input power at a particular plate node. The amplitude

of the input power at a frequency is equal to the scale factor q times the value in table qtb at the

corresponding frequency. This entry must be located in a load case defined by a pair of

SUBCASE and ENDSUBCASE entries.

Format:

PLATEB nid q qtb

Example:

PLATEB 100 90.0 1

Note:

nid The ID number of the node where the input power is prescribed. [integer]

q Scale factor. [Real]

qtb ID number of the DTABLE entry.

Remarks:

The bending input power from a normal point force applied on the plate can be calculated by:

mDF⋅

⋅=Π82

12

where F is the amplitude of the point force, m is the surface mass density of plate, D is the

bending stiffness of plate.

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PLATEF Point force on plate

Specify the frequency-dependent normal point force (Root-Mean-Square value) at a particular

plate node. The RMS value of the point force at a frequency is equal to the scale factor f times

the value in table ftb at the corresponding frequency. This entry must be located in a load case

defined by a pair of SUBCASE and ENDSUBCASE entries.

Format:

PLATEF nid f ftb

Example:

PLATEF 100 90.0 1

Note:

nid The ID number of the node where the input power is prescribed. [integer]

f Scale factor. [Real]

ftb ID number of the DTABLE entry.

Remarks:

The bending input power from a normal point force applied on the plate can be calculated by:

mDF⋅

=Π8

2

where F is the RMS value of the point force, m is the surface mass density of plate, D is the

bending stiffness of plate.

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PLATEIP Longitudinal input power on plate

Specify the frequency-dependent longitudinal input power at a particular plate node. The

amplitude of the input power at a frequency is equal to the scale factor q times the value in table

qtb at the corresponding frequency. This entry must be located in a load case defined by a pair of

SUBCASE and ENDSUBCASE entries.

Format:

PLATEIP nid q qtb

Example:

PLATEIP 100 90.0 1

Note:

nid The ID number of the node where the input power is prescribed. [integer]

q Scale factor. [Real]

qtb ID number of the DTABLE entry.

Remarks:

The longitudinal input power from an in-plane point force applied on the plate can be calculated

by:

( )h

ωFµν

161

21 2 −

where F is the amplitude of the point force, v is the Poisson’s ratio, ω is the radian frequency,

h is the thickness of plate, µ is the Lame’s first elastic constant for the plate.

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PLATESH In-plane shear input power on plate

Specify the frequency-dependent shear input power at a particular plate node. The amplitude of

the input power at a frequency is equal to the scale factor q times the value in table qtb at the

corresponding frequency. This entry must be located in a load case defined by a pair of

SUBCASE and ENDSUBCASE entries.

Format:

PLATESH nid q qtb

Example:

PLATESH 100 90.0 1

Note:

nid The ID number of the node where the input power is prescribed. [integer]

q Scale factor. [Real]

qtb ID number of the DTABLE entry.

Remarks:

The in-plane shear input power from a torsional moment applied on the plate can be calculated

by:

µν1282

1 2222 hkkωM L=Π

where M is the amplitude of the torsional moment, v is the Poisson’s ratio, ω is the radian

frequency, h is the thickness of plate, k is the transverse wave number, kL is the longitudinal

wave number, µ is the Lame’s first elastic constant for the plate.

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PWAVE Propagating wave field over plate

Specify the frequency-dependent propagating wavefield excitation on structural elements. This

information is typically generated from an EBEA analysis and provides the acoustic load

prescribed on the exterior part of a structure due to an external acoustic source. This entry is

used when the excitation originates from acoustic sources exterior to the structure. The energy

density value of the external propagating wavefield at a frequency is equal to the scale factor e

times the value in table etb at the corresponding frequency. This entry must be located in a load

case defined by a pair of SUBCASE and ENDSUBCASE entries.

Format:

PWAVE eid e rho0 c0 etb

Example:

PWAVE 100 90.0 1.21 343.0 1

Note:

eid The structural element ID where the external acoustic load is applied. [integer]

e Scale factor. [Real]

rho0 The ambient density of the external acoustic medium.[Real]

c0 The speed of sound in the external acoustic medium.[Real]

etb ID number of the DTABLE entry.

Remarks:

PWAVE excitation is used in the EFEA to model the exterior pressure loading over the outer

surface of the structure. The information for PWAVE excitation is typically generated from an

EBEA (Energy Boundary Element Analysis) analysis and provides the acoustic load prescribed

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60

on the exterior part of a structure due to an external acoustic source. The power transmission

coefficient from the exterior acoustic medium to the structure system is used to convert this

pressure loading into the input power in structure.

The power transmission coefficient from an acoustic medium to a plate can be calculated using

the radiation efficiency of the plate by:

σhfcρ

cρτ 2BS

300

PA =→

where 0ρ is the density of acoustic medium, Sρ is the material density of the plate, 0c is the

wave speed in the acoustic medium, Bc is the phase speed of bending wave in the plate, h is the

thickness of the plate, f indicates the frequency, σ is the radiation efficiency of the plate.

The parameter specified in the PWAVE load type is the acoustic energy density e of the exterior

wave field. The power of the impinging wave over a plate element can be determined by

Aecπ 0inc =

where A is the area of the plate element. Thus, the transmitted power into the plate is equal to

σehfcρAcρπτπ 2

phP

400

incPAtrans == → .

Remarks 2:

If some PWAVE excitations are applied to non-existed eid, the EFEA code will issue warning

message, and it will ignore those PWAVE entries and keep running.

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PWELD Connector Element Property

Defines the property of connector (CWELD) elements.

Format:

PWELD PID MID D Blank Blank MSET Blank TYPE

LDMIN LDMAX

Note:

PID Property identification number. [Integer]

MID Material identification number. [Integer]

D Diameter of the connector. [Real]

MSET Flag to eliminate m-set degrees-of-freedom (DOFs). [Character]

=OFF m-set DOFs are eliminated, constraints are incorporated in the stiffness.

=ON m-set DOFs are not eliminated, constraints are generated.

TYPE Character string indicating the type of connection. [Character]

=blank general connector

=”SPOT” spot weld connector

LDMIN Smallest ratio of length to diameter for stiffness calculation. [Real]

LDMAX Largest ratio of length to diameter for stiffness calculation. [Real]

Remarks:

The format of PWELD card in EFEA is exactly the same as in Nastran. Please refer to Nastran

Quick Reference Guide for more detail.

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PWSEAM Seam Connector Element Property

Defines the property of seam connector (CWSEAM) elements.

Format:

PWSEAM PID MID W T

Note:

PID Property identification number. [Integer]

MID Material identification number. [Integer]

W Width of the seam. [Real]

T Thickness of the seam. [Real]

Remarks:

The format of PWSEAM card in EFEA is exactly the same as in Nastran. Please refer to Nastran

Quick Reference Guide for more detail.

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RADEFF Calculating the radiation efficiency using Rummerman’s method

Specify property data set for the stiffened plate elements whose radiation efficiency will be

calculated using Rummerman’s method.

Format:

RADEFF pid Ap L Ab ρb

Example:

RADEFF 2 16.0 8.0 0.004 2700.0

Note:

pid Same ID as that in PLATE card. [Integer]

Ap The radiation area of the plate. [Real]

L The total length of the attached stiffeners [Real]

Ab The cross section area of the stiffeners. [Real]

ρb The material density of attached stiffeners.[Real]

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REFE Reference value for energy density

Define the reference value for dB of energy density calculation.

Format:

REFE ref

Example:

REFE 1.0E-12

Note:

ref Reference value.

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REFSPL Reference value for SPL (Sound Pressure Level)

Define the reference value and the factor utilized in the SPL calculation.

Format:

REFSPL ref fac

Example:

REFSPL 4.0E-10 1.42E5

Note:

ref Reference value for SPL calculation (for mean square value).

fac Value of ‘rho0*c0^2’ for the acoustic medium.

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RIB Stiffener property definition

Specify a physical property data set for stiffeners.

Format:

RIB id rmid A Iy Iz J Ix y0 z0 ky kz Γ

Example:

RIB 1 1 1.011E-4 5.364E-9 2.298E-8 3.55E-11 2.834E-9 0 0 0 0 0

Note:

id A unique ID number associated with the data set. [integer]

rmid The corresponding MRIB ID number of the stiffener.[integer]

A The cross section area of the stiffener [Real]

Iy,Iz The bending moment of inertia of the stiffener.[Reals]

J The torsion constant of the stiffener [Real]

Ix The polar moment of inertia of the stiffener [Real] (Ix=Iy+Iz)

y0,z0 The coordinates of the centroid of the stiffener (the origin of the coordinate is the shear

center of the stiffener) [Real]

ky,kz The shear coefficient of the stiffener.[Real]

Γ The warp torsion constant of the stiffener.[Real]

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SUBCASE Subcase delimiter

Delimit and identify a subcase. Multiple load cases can be defined in the EFEA model. A new

load case must begin with SUBCASE entry, and end with ENDSUBCASE entry. Any kinds of

excitations and/or constraints can be specified between a pair of these two entries to define a load

case.

Format:

SUBCASE n

Example:

SUBCASE 2

Note:

n Load case ID. [Integer]

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TBL TBL excitation over plate

Specify the TBL excitation on structure, so that a TBL pressure with property ID tblid is applied

to the structural elements with property IDs pid1, pid2 …. This entry must be located in a load

case defined by a pair of SUBCASE and ENDSUBCASE entries.

Format:

TBL tblid pid1 pid2 pid3 …

Example:

TBL 100 1 2 3

Note:

tblid ID number refers to TBLFLD entry. [integer]

pidi ID number refers to PLATE entry where the TBL is applied. [integer]

Remarks:

TBL is used to model a boundary layer flow excitation over the surface area of a plate or shell.

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TBLCOR Flow direction of TBL

Define the leading edge node as (x1, y1, z1) and the flow direction as vector from (x1,

y1, z1) to (x2, y2, z2) for the turbulent boundary layer excitation.

Format:

TBLCOR x1 y1 z1 x2 y2 z2

Example:

TBLCOR 0.0 0.0 0.0 1.0 0.0 0.0

Note:

xi x-coordinate. [Real]

yi y-coordinate. [Real]

zi z-coordinate. [Real]

Remarks:

The vector from (x1, y1, z1) to (x2, y2, z2) define the direction of the TBL flow

(direction of U0 as shown in the following figure).

Leading edge node

Structure

TBL U0

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TBLFLD Fluid property of TBL

Define the fluid property of turbulent boundary layer.

Format:

TBLFLD tblid rho v u0 c1 c2

Example:

TBLFLD 100 1.21 20.0 3

Note:

tblid TBL fluid property ID number. [integer]

rho Density of fluid. [Real]

v Kinetic viscosity of fluid [Real]

u0 Free stream velocity of fluid [Real]

c1 Stream-wise decay constant [Real]

c2 Span-wise decay constant [Real]

Remarks:

This entry is used to model a boundary layer flow excitation over the surface area of a

plate or shell. The pressure spectrum pφ of TBL is calculated by

( )133.1

02

0

2

021

2/1

2

20242 025.01

1

3

−−

+

+

+

+=

U

U

UcUUp

ωδ

ωδ

ωδ

δωρωφ τ

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71

where ρ is the density of fluid, ω is the radian frequency, 0U is the free stream velocity

of fluid, 1c is the stream-wise decay constant,

ρττ wU = ,

and 2.0

0

20029.0

=

LUUw

νρτ , and 2.0

0

37.0

=

LUL νδ ,

where v is the kinetic viscosity of fluid, and L is the linear length from the leading edge.

After establishing the wall pressure spectrum as shown above, the corresponding point

force spectrum can be determined by

( ) ( ) ( ) ipcni kcCF ∆= ωφω 314

where 0U

kcω

= , i∆ is the allocated area for ith node in the corresponding EFEA model,

and c

n kcC

2

1= , 2c is the span-wise decay constant.

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TBLPLATE Additional property definition for TBL-contacted plate element

Specify additional physical property data set for TBL-contacted plate element.

Format:

TBLPLATE pid t E ρ ν

Example:

TBLPLATE 2 1.905e-3 8.98E+10 2218.0 0.2751

Note:

pid The corresponding PLATE ID number for the plate. [Integer]

t The corrected thickness of the plate. [Real]

E Corrected Young’s modulus. [Real]

ρ Corrected mass density. [Real]

ν Corrected Poisson’s ratio. [Real]

Remarks:

1. TBLPLATE provides additional plate information to calculate the input power

induced by TBL excitation. It may be defined if both of below are satisfied: (1) the plate

is contacted with TBL; (2) the plate is treated by trim panel.

2. When TBLPLATE is defined, the PLATE definition with ID number pid and its

corresponding MPLATE definition should exist. In such a case, when calculating input

power induced by TBL, the thickness t, Young’s modulus E, mass density ρ, and

Poisson’s ratio ν that defined in the corresponding PLATE and MPLATE definitions are

replaced by those defined in TBLPLATE definition.

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3. When calculating corrected plate properties, light and soft materials in plate treatment

(such as fiberglass) are usually ignored.

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TMMAT Acoustic treatment material property definition

Defines the frequency-dependent trim material used in the model.

Format:

TMMAT mid alpha density iloss alphatb

Example:

TMMAT 1 0.2 3.6 0.13 1

Note:

mid ID number of a trim material [Integer]

alpha Scale factor for defining the frequency-dependent acoustic absorption

coefficient of the trim material. The value of the acoustic absorption

coefficient is equal to the scale factor alpha times the value in table

alphatb at the corresponding frequency.

density Density of the trim material [real]

iloss Insertion loss of the trim material [Real]

alphatb ID number of the DTABLE entry.

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Section 2:

Specifies the information about the structural model, including the nodal coordinates,

element types, connectivity, the plate-plate joint information, and the beam to plate joint

information. All nodes and elements are defined in NASTRAN short fixed format. All

joints are typically generated automatically by the Pre-EFEA code.

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BPJOINT Beam-to-plate connection

Define a beam to plate(s) joint in the finite element model.

Format:

BPJOINT ne

eB n1 n2

eP1 n1 n2

:

ePne-1 n1 n2

Example:

BPJOINT 3

11 101 102

51 501 502

61 601 602

Note:

ne The number of elements at the joint (including the beam element) [integer]

eB The ID of the beam element at the joint.[integers]

eP1 The IDs of the plate elements at the joint.[integers]

:

ePne-1

n1,n2 The node IDs of the corresponding elements at the joint.[integers]

Remarks:

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This entry is used to model the plate-to-plate(s) joint with a stiffener attached, and the

stiffener itself is represented by a set of beam (CBAR) elements (the stiffener has its own

degrees of freedom in the EFEA model). Please be noted that the PJOINT card can also

be used to model the plate-to-plate(s) joint with a stiffener attached, the stiffener itself in

PJOINT card is defined as a physical property but not elements (there is no additional

degrees of freedom for the stiffener in the EFEA model). In the following figures, on left

shows the prototype of a general plate-to-plate connection with a stiffener attached on the

junction. On right shows the corresponding EFEA elements with the joint defined by

BPJOINT card. It can be found that the stiffeners are represented by a set of CBAR

elements.

Plate 1 Plate 2

Stiffener

Depiction of plate-to-plate joint with a stiffener attached

EFEA elements for plate-to-plate joint with a stiffener attached using BPJOINT card;

the stiffener is modeled explicitly with elements (Different parts are offset for demonstration purpose)

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CBAR Beam element

Define a linear (2-noded) beam element in NASTRAN short fixed format.

Format:

CBAR eid pid GA GB

Example:

CBAR 1 1 11 12

Note:

eid A unique ID number that is to be associated with the element.[integer]

pid The ID number of PBAR entry for the beam element.[integer]

GA The ID numbers of the first nodes comprising the element [integers]

GB The ID numbers of the second nodes comprising the element [integers]

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CBUSH Generalized Spring-and-Damper Connection

Define a generalized spring-and-damper structural element.

Format:

CBUSH eid pid GA GB GO/X1 X2 X3 CID

S OCID S1 S2 S3

Note:

eid A unique element identification number. [Integer]

pid Property identification number of a PBUSH entry. [Integer]

GA,GB Grid Point identification number of connection points. [Integer]

Xi Components of orientation vector v from GA, in the displacement

coordination system of GA. [Real]

GO Alternate method to supply vector v using grid point GO. Direction of v

is from GA to GO. v is then transferred to End A. [Integer]

CID Element coordinate system identification. A 0 means the basic coordinate

system. If CID is blank, then the element coordinate system is determined

from GO or Xi. [Integer]

S Location of spring damper. [Real]

OCID Coordinate system identification of spring-damper offset. [Integer]

S1,S2,S3 Components of spring-damper offset in the OCID coordinate system if OCID > 0. [Real]

Remarks:

The format of CBUSH card in EFEA is exactly the same as in Nastran. Please refer to

Nastran Quick Reference Guide for more detail.

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CFAST A Shell Patch Fastener Connection

Defines a fastener with material orientation connecting two surface patches.

Format:

CFAST eid pid TYPE IDA IDB GS GA GB

XS YS ZS

Note:

eid A unique element identification number. [Integer]

pid Property identification number of a PFAST entry. [Integer]

TYPE Specifies the surface patch definition: [Character]

If TYPE = ‘PROP’, the surface patch connectivity between patch A and

patch B is defined with two PSHELL (or PCOMP) properties with

property ids given by IDA and IDB.

If TYPE = ‘ELEM’, the surface patch connectivity between patch A and

patch B is defined with two shell element ids given by IDA and IDB.

IDA,IDB Property id (for PROP option) or Element id (for ELEM option) defining

patches A and B. [Integer]

GS Grid point defining the location of the fastener. [Integer]

GA,GB Grid ids of piecing points on patches A and B. [Integer]

XS,YS,ZS Location of the fastener in basic. Required if neither GS nor GA is

defined. [Real]

Remarks:

The format of CFAST card in EFEA is exactly the same as in Nastran. Please refer to

Nastran Quick Reference Guide for more detail.

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CQUAD4 Quadrilateral plate element

Define a linear (4-noded) quadrilateral plate element in NASTRAN short fixed format.

Format:

CQUAD4 eid pid n1 n2 n3 n4 theta

Example:

CQUAD4 1 1 11 12 13 14 80

Note:

eid A unique ID number associated with the element.[integer]

pid The ID number of the physical property data set for the element.[integer]

ni The ID numbers of the nodes comprising the element.[integers]

theta Material property orientation angle in degrees (only for anisotropic plate).[real]

Figure 1 CQUAD4 element geometry and coordinate systems

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Remarks:

CQUAD4 data cards are translated by Pre-EFEA code from Nastran format CQUAD3

and CQUADR data cards.

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CTRIA3 Triangular plate element

Define a linear (3-noded) triangular plate element in NASTRAN short fixed format.

Format:

CTRIA3 eid pid n1 n2 n3 theta

Example:

CTRIA3 1 1 11 12 13 80

Note:

eid A unique ID number associated with the element.[integer]

pid The ID number of the physical property data set for the element.[integer]

ni The ID numbers of the nodes comprising the element.[integers]

theta Material property orientation angle in degrees(only for anisotropic plate).[real]

Figure 2 CTRIA3 element geometry and coordinate systems

Remarks:

CTRIA3 data cards are translated by Pre-EFEA code from Nastran format CTRIA3 and

CTRIAR data cards.

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CWELD Weld or Fastener Element Connection

Defines a weld or fastener connecting two surface patches or points.

Format:

CWELD eid pid GS “PARTPAT” GA GB

PIDA PIDB

XS YS ZS

Note:

eid A unique element identification number. [Integer]

pid Property identification number of a PWELD entry. [Integer]

GS Identification number of a grid point which defines the location of the

connector. [Integer]

“PARTPAT” Character string indicating the type of connection. The format of the

subsequent entries depends on the type. “PARTPAT”, for example,

indicates that the connectivity of surface patch A to surface patch B is

defined with two property identification numbers of PSHELL entries,

PIDA and PIDB, respectively. The “PARTPAT” format connects up to

3x3 elements per patch.

GA, GB Grid point identification numbers of piercing points on surface A and

surface B, respectively. [Integer]

PIDA, PIDB Property identification numbers of PSHELL entries defining surface A

and B respectively. [Integer]

XS, YS, ZS Coordinates of spot weld location in basic. [Real]

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Remarks:

The format of CWELD card in EFEA is exactly the same as in Nastran. Please refer to

Nastran Quick Reference Guide for more detail.

Besides “PARTPAT”, there are other alternate formats, such as “ELPAT”, “ELEMID”,

“GRIDID” and “ALIGN”. They are also in the exact same format as in Nastran. Please

refer to Nastran Quick Reference Guide for more detail.

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CWSEAM A Shell Patch Seam Connection

Defines a seam element connecting two surface patches.

Format:

CWSEAM eid pid Blank “GRIDID” Blank PIDA PIDB

GS GE

Alternate Format:

CWSEAM eid pid Blank “XYZ” Blank PIDA PIDB

XS YS ZS XE YE ZE

Note:

eid A unique element identification number. [Integer]

pid Property identification number of a PWELD entry. [Integer]

LTYPE Connectivity search type. [Character]

If LTYPE=”GRIDID”, location is defined by GS and GE.

If LTYPE=”XYZ”, location is defined by two XYZ locations.

PIDA,PIDB Property identification numbers of PSHELL entries defining surface A

and B respectively. [Integer]

GS, GE Grid identification numbers of piercing points on surface A and B of the

start and end of the seam. [Integer]

XS,YS,ZS Location of the start of the seam in basic coordinate system. [Real or

blank]

XE,YE,ZE Location of the end of the seam in basic coordinate system. [Real or

blank]

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Remarks:

The format of CWSEAM card in EFEA is exactly the same as in Nastran. Please refer to

Nastran Quick Reference Guide for more detail.

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GRID Grid point

Define a node of the finite element model using NASTRAN short fixed format.

Format:

GRID id xc yc zc

Example:

GRID 1 1.0 1.0 1.0

Note:

id A unique ID number associated with the node.[integer]

xc The global x-coordinate of the node.[Real]

yc The global y-coordinate of the node.[Real]

zc The global z-coordinate of the node.[Real]

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ISOLATOR Isolator

Define an isolator between a beam and a plate in the finite element model.

Format:

ISOLATOR 1 id

eP nP

eB nB

Example:

ISOLATOR 1 1

11 101

12 102

Note:

id The ID number of ISO entry for the isolator.[integer]

eP The ID of the plate element connected by the isolator. [integers]

eB The ID of the beam element connected by the isolator. [integers]

nP The node IDs of the corresponding plate elements at the joint. [integers]

nB The node IDs of the corresponding beam elements at the joint. [integers]

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PJOINT Plate-to-plate joint

Define a plate-to-plate joint with (regular or periodic) or without stiffener (if no stiffeners

both #rib and #rpid should be blank, see Remarks).

Format:

PJOINT ne #rib #rpid

e1 n1 n2

e2 n1 n2

:

en n1 n2

Example:

PJOINT 3

11 101 102

51 501 502

61 601 602

Note:

ne The number of plate elements to form the joint (maximum value 10). [integer]

#rib Refers to the ID number in RIB entry.

This parameter is used to define a stiffener (which is simulated as a physical

property, and not as an independent element, in the EFEA formulation)

#rpid Refers to PSID parameter in EFEA_PS entry.

This parameter is used to define a periodic stiffener at the joint.

If no stiffener or there is only regular stiffener at the joint, #rpid should be blank.

ei The ID number of the elements comprising the joint.[integers]

n1,n2 The ID number of the nodes that are coincident at the joint.[integers]

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Remarks:

• If there is no stiffener at the joint, both #rib and #rpid must be blank or zero.

• If there is a regular (non-periodic) stiffener at the joint, then #rib must be non-

zero, and #rpid must be blank or zero.

• If there is a periodic (non-regular) stiffener at the joint, then #rib must be zero,

and #rpid must be non-zero.

• Tips: If #rpid is non-zero, #rib must be zero. If #rib is non-zero, #rpid must be

blank or zero.

• If any ei does not exist, the EFEA code will issue an error message and stop.

Please be noted that the BPJOINT card can also be used to model the plate-to-plate(s)

joint with a stiffener attached, there the stiffener itself is represented by a set of beam

(CBAR) elements (therefore the stiffener has its own degrees of freedom in the EFEA

model). In the following figures, on left shows the prototype of a general plate-to-plate

connection with a stiffener attached on the junction. On right shows the corresponding

EFEA elements with the joint defined by PJOINT card.

Plate 1 Plate 2

Stiffener

Depiction of plate-to-plate joint with a stiffener attached

EFEA elements for plate-to-plate joint with a stiffener attached using PJOINT card.

The stiffener is not modeled with elements but its presense affects the power transfer characteristics

between the plate elements. (Different parts are offset for demonstration purpose)

Joint through stiffener

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Section 3:

Includes the information about the acoustic model, including the nodal coordinates,

element types and connectivity. NASTRAN short fixed format is required for defining

entries in this Section.

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CHEXA Hexahedral acoustic element

Define a linear (8-nodes) hexahedral acoustic element in NASTRAN short fixed format.

This entry spans two lines in the file (a ‘+’ sign must be on the first column of the second

line).

Format:

CHEXA eid mid n1 n2 n3 n4 n5 n6

+ n7 n8

Example:

CHEXA 1 1 11 12 13 14 15 16

+ 17 18

Note:

eid A unique ID number associated with the element. [integer]

mid The ID number of the material property data set for the acoustic element.

(defined in a PACOUS entry) [integer]

ni The ID numbers of the nodes comprising the element(Fig.1).[integers]

Figure 1 Hexahedral element

n2

n6

n3

n7

n4

n1

n5

n8

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CPENTA Pentahedral acoustic element

Define a linear (6-nodes) pentahedral acoustic element in NASTRAN short fixed format.

Format:

CPENTA eid mid n1 n2 n3 n4 n5 n6

Example:

CPENTA 1 1 11 12 13 14 15 16

Note:

eid A unique ID number associated with the element. [integer]

mid The ID number of the material property data set for the acoustic element.

(defined in a PACOUS entry) [integer]

ni The ID numbers of the nodes comprising the element. (Fig.2) [integers]

Fig 2 Pentahedral element

n1

n3 n2

n4

n5 n6

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CTETRA Tetrahedral acoustic element

Define a linear (4-nodes) tetrahedral acoustic element in NASTRAN short fixed format.

Format:

CTETRA eid mid n1 n2 n3 n4

Example:

CTETRA 1 1 11 12 13 14

Note:

eid A unique ID number associated with the element. [integer]

mid The ID number of the material property data set for the acoustic element.

(defined in a PACOUS entry) [integer]

ni The ID numbers of the nodes comprising the element. (Fig.3) [integers]

Fig 3 Tetrahedral element

n1

n2

n3

n4

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Section 4:

Defines the plate-to-acoustic or the acoustic-to-plate-to-acoustic joint information.

Typically, these cards are generated automatically by the Pre-EFEA code.

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JACPLAC Acoustic-to-plate-to-acoustic joint

Define an Acoustic-to-Plate-to-Acoustic joint in the energy finite element model. Note,

this entry spans four lines in the file. The key word JPACLAC occupies one line.

Format:

JACPLAC

e1 pid n11 n12 n13 n14

e2 mid1 n21 n22 n23 n24

e3 mid2 n31 n32 n33 n34

Example:

JACPLAC

1 1 11 12 13 14

11 10 101 102 103 104

12 20 201 202 203 204

Note:

e1 The ID number of the plate element comprising the joint. [integer]

pid The physical property ID (defined in a PLATE entry) of the plate element.

n11, n12, n13, n14

The ID numbers of the nodes comprising the plate element at the joint.(Fig.6)

[integers] If the plate element is a triangular element, n14 doesn’t exist. (Fig.7)

e2 The ID number of the acoustic element at one side of the joint. [integer]

mid1 The material property ID (defined in a PACOUS entry) of the acoustic element.

n21, n22, n23, n24

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The ID numbers of the nodes of the acoustic element at the joint, coincident with

those of the plate element (Fig.6). If the surface at the joint of the acoustic

element is a triangular element, n24 doesn’t exist. (Fig.7)

e3 The ID number of the acoustic element at another side of the joint. [integer]

mid2 The material property ID (defined in a PACOUS entry) of the acoustic element.

n31, n32, n33, n34

The ID numbers of the nodes of the acoustic element at the joint, coincident with

those of the plate element. (Fig.6). If the surface at the joint of the acoustic

element is a triangular element, n34 doesn’t exist. (Fig.7)

Fig.6 Acoustic-to-Plate-to-Acoustic joint with quadrilateral element

Fig.7 Acoustic-to-Plate-to-Acoustic joint with triangular element

n21

n22

n24

n23

n11

n12

n13

n14

n31

n32

n34

n33

n22

n21

n23

n12

n13

n11 n31

n33

n32

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JPLAC Plate-to-acoustic joint

Define a Plate-to-Acoustic joint in the energy finite element model. Note, this entry

spans three lines in the file. The keyword JPLAC occupies one line.

Format:

JPLAC

e1 pid n11 n12 n13 n14

e2 mid n21 n22 n23 n24

Example:

JPLAC

1 1 11 12 13 14

11 10 101 102 103 104

Note:

e1 The ID number of the plate element comprising the joint. [integer]

pid The property ID (defined in a PLATE entry) of the plate element.

n11, n12, n13, n14

The ID numbers of the nodes comprising the plate element at the joint (Fig.4) If

the plate element is a triangular element, n14 doesn’t exist (Fig.5).

e2 The ID number of the acoustic element comprising the joint. [integer]

mid The material ID (defined in a PACOUS entry) of the acoustic element. [integer]

n21, n22, n23, n24

The ID numbers of the nodes of the acoustic element at the joint, coincident with

those of the plate element. (Reference Fig.4)[integers]. If the surface at the joint

of the acoustic element is a triangular element, n14 doesn’t exist. (Reference

Fig.5)

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Fig 4 P-A joint with quadrilateral element

Fig 5 P-A joint with triangular element

n21

n22

n24

n23

n11

n12

n13

n14

n22

n21

n23 n12

n13

n11

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Section 5:

Defines the acoustic treatment and the acoustic leakage.

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JACPLAC Leakage over the plate

The JACPLAC card needs to be modified in order to include the openings on the

separating plate at the joint.

Format:

JACPLAC lgid

e1 pid n11 n12 n13 n14

e2 mid1 n21 n22 n23 n24

e3 mid2 n31 n32 n33 n34

Example:

JACPLAC 1

1 1 11 12 13 14

11 10 101 102 103 104

12 20 201 202 203 204

Note:

lgid The ID number of an opening in the separating plate defined in LGOPENING

entry [integer].

Rest of parameters are the same as that in above JACPLAC entry.

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TMDFACE Acoustic treatment

Define the location of the trimmed face and the material ID of the treatment. The acoustic

treatment can be only applied on the outer surface of acoustic element.

Format:

TMDFACE fmid n1 n2 n3 [n4]

Example:

TMDFACE 1 11 12 13 14

Note:

fmid The ID number of a trim material defined in the TMMAT card [integer]

n1, n2, n3, [n4]

The node IDs of acoustic elements comprising the trimmed face [integers]

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IV. Output of the EFEA Analysis

Based on the user’s selection (entered using the OUTFILE function), the EFEA program

will output the nodal results in “outputfile.txt” text file (this is the default output file if the

user doesn’t define the OUTFILE entry), or “outputfile.pch” NASTRAN punch file, or

“outputfile.mat” MATLAB file. The listed components in the result file are determined

by OUTSTR, or OUTACS, or OUTBM entries defined in the EFEA input data file.

When the parameter PATRAN is defined in the OUTFILE entry, multiple result files in

PATRAN ‘nod’ format will be created, each of which corresponds to a combination of

one analyzed frequency and one subcase. The names of these multiple results file are in

the form of “s_freq=XXX_subcase=YYY.nod” for plate elements results, and

“a_freq=XXX_subcase=YYY.nod” for acoustic elements results. In these sample file

names, ‘XXX’ is the frequency value, and ‘YYY’ is the subcase ID. A template file

“snod.res_tmpl” for plate elements, and “anod.res_tmpl” for acoustic elements will also

be created for post-processing the results in PATRAN.

Generally, bending energy density, in-plane energy density, and transverse velocity are

the three types of output variables for the nodes of the plate elements. For the nodes of

the acoustic elements, the output variables are acoustic energy density, acoustic pressure,

and sound pressure level. Bending 1 energy density, bending 2 energy density,

longitudinal energy density, and torsion energy density can be output for the nodes of the

beam element.

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Appendix A. Pre-EFEA code

The Pre-EFEA code is used to create the EFEA input data files. The finite element

model constructed using a pre-processor comprises the input for the Pre-EFEA code.

The pre-EFEA code detects all geometric features, changes in material properties,

intersections between components, interfaces between structural and acoustic elements,

and it automatically performs the following actions:

• disconnects the model at each joint location by adding appropriate nodes

and by updating the connectivity of the elements

• creates all the necessary joints among structural elements or between

structural and acoustic elements

• creates the “model-all” file which contains all the nodes and elements for

the structural and acoustic parts of the model (with modified node

numbers and accordingly updated element connectivity at the joints), and

all the necessary cards which define the joint connections

Required data files:

Two files are required for the Pre-EFEA code. The first one contains the entire finite

element model as generated by any general purpose pre-process. This file must be in

NASTRAN short fixed file format. The second one is called “data.inp” and contains

control information about the Pre-EFEA analysis.

File 1- A NASTRAN input data file:

The following information should be included in the file for ALL elements of the finite

element model:

GRID

CQUAD4 or CTRIA3

CBAR or CBEAM

CHEXA, CPENTA or CTETRA

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PSHELL

MAT1

In this file, the grid coordinates can be defined in local coordinate systems, and the local

coordinate systems can be rectangular, cylindrical, and spherical coordinate systems.

However, the Pre-EFEA code will translate the grid coordinates of these grids from local

coordinate systems to the global rectangular coordinate system.

The Pre-EFEA code allows the user to use ‘INCLUDE’ data cards in this Nastran data

file to include additional data files.

File 2- The “data.inp” file:

Contains the following information:

FILE nastran.dat

Specify the NASTRAN input data file name. The length of the file name

(including the extension) should not exceed 16 characters.

ANGLE α

Specify the criterion value of the angle to identify the P-P joints

(Default value is o5 ). Unit: degree

DIST d

Specify the criterion value of the distance between plate element to

acoustic element which is used to identify the P-A joints

(Default value is 6100.1 −× ).

PLANE zyx nnn ,,

Specify the normal vector of the waterline plane (outward to the water)

BASE bbb zyx ,,

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Specify the base point of the waterline plane, which can be an arbitrary

point located on the waterline plane.

STIFFENER

When beam elements exist in the Nastran input data file the user has the

option to define the connection between the beam and the plate elements

either through the BPJOINT connection (default) or by using the

PJOINT connection. When the key word “STIFFENER” is included in

the “data.inp” file then the PJOINT connections are generated.

EFEA_PS PSID PSSTYLE RID PID

Define the periodic stiffeners attached to the plate (or cylinder).

PSID The user specified ID for the periodic stiffener

PSSTYLE The periodic stiffener type

=1 Ring periodic stiffeners attached to a cylinder

=2 Axial periodic stiffeners attached to a cylinder

=3 Periodic stiffeners (simulated as plate elements)

attached to a flat plate

RID If PSSTYLE=1, or 2, RID refers to the ID number of PBAR

(or PBEAM) card in Nastran data file, which simulate the

stiffeners attached to a cylinder.

If PSSTYLE=3, RID refers to the ID number of PSHELL

card in Nastran data file, which refers to a group of plate

elements which act as the periodic stiffeners attached to a

flat plate.

PID Refers to the ID number of PSHELL card in Nastran data

file, which refers to a group of plate elements where the

periodic stiffeners are attached.

JGRID_OUT

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Require the Pre-EFEA code to output a list of new generated nodes for

PJOINT and BPJOINT cards. The grid information is output to file

‘jgrid.txt’. Every line of this file has 3 integer numbers. The first number

is the new grid ID, the second one is the corresponding old grid ID, and

the third one specifies the joint type (1 for PJOINT, and 2 for BPJOINT).

Output:

A single file will be created under the name “model-all”. It contains the majority of the

information for the EFEA analysis.