MD Nastran 2010 Loads Management User's Guide (Pre-Release)

MD Nastran 2010- Loads Management User’s Guide

MD Nastran 2010

Loads Management User’s Guide(Pre-Release)

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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.

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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. June 25, 2010

MDNA:2010:Z:Z:Z:DC-LDM

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MD Nastran 2010 Installation and Operations Guide

Preface

List of Nastran Books

Technical Support

Internet Resources


iv

List of Nastran BooksBelow is a list of some of the Nastran documents. You may find any of these documents from MSC.Software at www.simcompanion.mscsoftware.com.

Installation and Release Guides

• Installation and Operations Guide

• Release Guide

Guides

Reference Books

• Quick Reference Guide

• DMAP Programmer’s Guide

• Reference Manual

User’s Guides

• Getting Started

• Linear Static Analysis

• Dynamic Analysis

• MD Demonstration Problems

• Thermal Analysis

• Superelements

• Design Sensitivity and Optimization

• Implicit Nonlinear (SOL 600)

• Explicit Nonlinear (SOL 700)

• Aeroelastic Analysis

• User Defined Services

• EFEA User’s Guide

• EFEA Tutorial

• EBEA User’s Guide

vMD Nastran 2010 Installation and Operations Guide

Preface

Technical SupportFor technical support phone numbers and contact information, please visit: http://www.mscsoftware.com/Contents/Services/Technical-Support/Contact-Technical-Support.aspx

Support Center (www.simcompanion.mscsoftware.com)

Support Online. The Support Center provides technical articles, frequently asked questions and documentation from a single location.

http://www.mscsoftware.com/Contents/Services/Technical-Support/Contact-Technical-Support.aspx

www.simcompanion.mscsoftware.com


vi

Internet ResourcesMSC.Software (www.mscsoftware.com)

MSC.Software corporate site with information on the latest events, products and services for the CAD/CAE/CAM marketplace.

C o n t e n t sLoads Management User’s Guide

Preface

List of Nastran Books iv

Technical Support v

Internet Resources vi

1 Loads Management

Introduction 2Multiple FEM models 2Multiple loading conditions 2Revisions 2

Overview of Solution Functionality 4Loads management 4Solution vector management 5Data recovery 5

Command Language 6Loads management 6Solution vector management 8Data recovery 11Other Commands 13

Limitations 15Combine Loads & Combine Disps 15Thermal Loads 15Sequence Dependence 15Load Combinations 16Superelements 16

Example Command Scripts 17Script1: Read in the model information and store on Nastran DB 17Script 2: Add 3 load cases and solve them 17Script 3: Combine load cases and solve them 18Script 4: Combine displacements 18Script 5: Delete/combine loads/displacements and solve 18

Loads Management User’s Guide

viii

Script 6: Recover results from 2 Nastran DBs and save results in an XDB 19Script 7: Recover results from a Nastran DBs and save results in 2 XDBs 20

Chapter 1: Loads ManagementLoads Management User’s Guide

1 Loads Management

Introduction 2

Overview of Solution Functionality 4

Command Language 6

Limitations 15

Example Command Scripts 17

Loads Management User’s GuideIntroduction

2

IntroductionThe internal loads management process of the aircraft design which normally involves static analysis of the airframe due to various loading conditions, poses a number of challenges to the analyst. This document describes challenges specific to this process and presents an extension to the Statics solution of MD Nastran that addresses these challenges.

Some of the challenges involved include:

Multiple FEM modelsThere may be a number of vehicle level FEM models that have to be analyzed and whose results have to be somehow combined. For example, there may be models with and without doors. There may also be models with and without landing gear. Analysis results related to these models will have to be combined to produce critical loads used in subsequent steps.

Multiple loading conditionsInternal loads analysis process may include more than 10,000 unique load cases due to flight maneuvers, ground load cases, cabin pressure, cargo loads, and thermal loads. Loads from these various sources will have to be combined to achieve critical loads used for design.

RevisionsThe loads passed on to the internal loads team frequently change. Changes may be due to model changes or new maneuver loads from the external loads process. Revisions normally do not affect the entire set of loads but only a small fraction-up to 10% of the load cases.

Figure 1-1 shows the internal loads management process as it relates to the FEM model analysis. The traditional statics analysis in Nastran does cover the steps highlighted in green as part of an end-to-end solution, but it does not provide users with access to independent steps of this process. For example, in traditional statics analysis, the user cannot change few load cases and perform data recovery without having to rerun all load case.

The solution presented in this document provides users with a lower level of access to individual steps in the Statics solution in MD Nastran. So changes in load cases or solution vectors do not necessarily require a complete rerun of the model. This level of control can result in significant improvements in overall process of internal loads management.

3Loads ManagementIntroduction

Figure 1-1 Model building

Loads Management User’s GuideOverview of Solution Functionality

4

Overview of Solution FunctionalityThe key functionality that supports the internal loads process is the componentization of the Statics solution in MD Nastran that allows for the close alignment of the solution steps with the engineering process steps. The diagram below shows the components of the Statics solution that can now be individually called upon. It also shows the dependencies the components may have on one another.

The internal loads solution capabilities can be categorized in the following groups:

Figure 1-2 Componentized MD solution

Loads managementLoads can now be partially modified without the need to rerun the analysis with the entire set of loads. Load cases can be incrementally added, deleted, or combined. User can also get a report on the current contents of the database in terms of loads. These operations can be driven through a high level command language described in the next section.

5Loads ManagementOverview of Solution Functionality

Solution vector managementSimilar to how loads are individually managed, users also have full control in generating individual solution vectors associated with load vectors. Individual solution vectors can be generated, combined, or deleted. User can also get a report on the current contents of the database in terms of solution vectors. These operations can also be driven through a high level command language described in the next section.

Data recoveryUsers can generate results on a given subset of the model and/or a subset of load cases. So when a subset of loads are modified, it is not necessary to regenerate all results. Data recovery operations can also be driven through a high level command language described in the next section.

Loads Management User’s GuideCommand Language

6

Command LanguageA high level command language has been designed to perform the operations described in the previous sections. A sequence of commands can be put into a file and submitted to Nastran for batch processing. Care is taken so that the like commands are grouped together to increase performance. For example a sequence of SOLVE commands are combined together so that only a single call to the FBS (forward-backward substitution) module takes place.

The commands fall into the following categories:

Loads management

Description: Add load case to the database

Command: DEFINE LOAD <LABEL> USING <ID> FROM <file>

Action:

There are two cases to consider:

a. If LABEL exists on the database then

• Existing Load case is deleted

• New load case is inserted with new load from "file" and is associated with given set ID

• It is required that both LABELs and IDs are unique, i.e. LABEL and ID have a one to one associativity. If given set ID exists on the database a User Fatal Message is issued

b. If LABEL does not exist on the database

• New load case is inserted with new load from "file" and is associated with given set ID

• If given set ID exists on the database a User Fatal Message is issued

Example:$ Add test load caseDEFINE LOAD 'TEST LOAD CASE 3001'USING 3001FROM '../../loads/ultimate/gear_up/C001.load'$ Add cabin pressureDEFINE LOAD '1.0 PSI CABIN PRESSURE'USING 2001FROM '../../loads/pressure/P001.load'

Description: Delete load case.

Command: DELETE LOAD <LABEL>

7Loads ManagementCommand Language

Action:


a. If LABEL exists on the database

• Load vector with given LABEL is deleted


• A warning message to this effect is given and execution continues

Example:$ Delete test load caseDELETE LOAD 'TEST LOAD CASE 3001'$ Delete cabin pressureDELETE LOAD '1.0 PSI CABIN PRESSURE'

Description: Create a new load case by combining existing load cases

Command: COMBINE LOADS <NEW_LABEL> FROM <COEF>* <LABEL> + …

Action:

There are again two cases to consider:

a. If NEW_LABEL exists on the database

• Load vector with given NEW_LABEL is deleted

• All load vectors are combined

• New load vector with NEW_LABEL is inserted

b. If NEW_LABEL does not exist on the database

• All load vectors are combined

• New load vector with NEW_LABEL is inserted

Note: Referential integrity is NOT preserved by the application, i.e. a LOAD can be deleted for an existing DISP (solution vector).

Note: If one of the load LABELs to be combined does not exist a Fatal message is issued and processing is stopped.

Note: If one of the load LABELs to be combined does not exist a Fatal message is issued and processing is stopped.


8

Example:$ combine loads from test load case 3001 and cabin pressureCOMBINE LOADS 'TEST LOAD CASE 3001 + CABIN PRESSURE'FROM 1.0 * 'TEST LOAD CASE 3001'

- 6.5 * '1.0 PSI CABIN PRESSURE'

$combine loads from a previous load combine step with test load cases 3002 and 3003COMBINE LOADS 'TEST LOAD CASE 3003 + 3002 + 3001 + CABIN PRESSURE'FROM 1.0 * 'TEST LOAD CASE 3003' + 1.0 * 'TEST LOAD CASE 3002' + 1.0 * 'TEST LOAD CASE 3001 + CABIN PRESSURE'

Description: Print a report of load cases currently on the database to the F06 file

Command: REPORT LOADS

Action:

Load case information is printed to F06. If no loads are found on the database at the time a report on loads is requested, a warning message to that effect is issued and the processing continues.

Example:$ print a report of loads on the databaseREPORT LOADS

A sample report is given below:

LOADS REPORT(AFTER COMBINE DISPS)

ID LABEL COMBINED DISP DATE TIME -- ----- -------- ---- ---- ---- 3001 C001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55100000000 C001 TEST LOAD CASE + 10.50 PSI CABIN PRESSURE YES NO FEB-09-2009 20:21.15100000000 C001 TEST LOAD CASE + 12.0 PSI YES YES FEB-09-2009 20:21.23100000001 C001 TEST LOAD CASE + 4.0 PSI UPPER/10.5 PSI LOWER YES NO FEB-09-2009 20:21.23 4001 D001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 7001 G001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 11001 K001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 13001 M001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 14001 N001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 15001 O001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 16001 P001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 1 P701 1.0 PSI CABIN PRESSURE NO YES FEB-09-2009 20:20.55 2 P702 1.0 PSI DECOMPRESSION PRESSURE NO YES FEB-09-2009 20:20.55 17001 Q001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 19001 S001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 20001 T001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55 21001 U001 TEST LOAD CASE NO YES FEB-09-2009 20:20.55

Solution vector management

Description: Generate displacements for load case with given label

Command: SOLVE LOAD <LABEL>


Action:


a. If solution vector for LABEL exists on the database

• Solution vector with given LABEL is deleted

• Load case with given LABEL is solved

• Solution vector with given LABEL is saved on database

b. If solution vector for LABEL does not exist on the database

• Load case with given LABEL is solved

• Solution vector with given LABEL is saved on database

Example:$ Generate displacements for test case 3001SOLVE LOAD 'TEST LOAD CASE 3001'$ Generate displacements for combined load case 3003 + 3002 + 3001 + cabin pressureSOLVE LOAD 'TEST LOAD CASE 3003 + 3002 + 3001 + CABIN PRESSURE'

Description: Delete displacement vector for load case with given label

Command: DELETE DISP <LABEL>

Action:


a. If LABEL exists on the database

• Solution vector with given LABEL is deleted


• A warning message to this effect is issued and prcoessing is continued

Examples:$ Delete displacements for test case 3001DELETE DISP 'TEST LOAD CASE 3001'$ Delete displacements for combined load case 3003 + 3002 + 3001 + cabin pressureDELETE DISP 'TEST LOAD CASE 3003 + 3002 + 3001 + CABIN PRESSURE'

Note: If the command file contains a contiguous set of solve commands, this set is grouped and solved together to achieve maximum performance.


10

Description: Create a new displacement vector by combining existing displacement vectors

Command: COMBINE DISPS <NEW_LABEL> FROM <COEF>* <LABEL> + …

Action:

There are again two cases to consider:

a. If NEW_LABEL exists on the database

• Solution vector with given NEW_LABEL is deleted

• All solution vectors given are combined

• New solution vector with NEW_LABEL is created

b. If NEW_LABEL does not exist on the database

• All solution vectors given are combined

• New solution vector with NEW_LABEL is created

Examples:$ combine displacement vectors to get displacements due to 5 PSICOMBINE DISPS 'C001 TEST LOAD CASE + 5.0 PSI UPPER/13.5 PSI LOWER'FROM 1.0 * 'C001 TEST LOAD CASE + 11.50 PSI CABIN PRESSURE'

- 6.5 * 'P702 1.0 PSI DECOMPRESSION PRESSURE'

Description: Print a report of displacement vectors currently on the database to the F06 file

Command: REPORT DISPS

Note: If one of the LABELs does not exist a Fatal message is issued and processing is stopped.

Note: 1. If one of the LABELs does not exist a Fatal message is issued and processing is stopped.

2. NEW_LABELs can be used in a subsequent COMBINE step.

Note: "Date" in the report indicates the date at which the solution vector was generated either by solve or combine.


Action:

Displacement vector information is printed to F06. If no displacement vectors are found on the database at the time a report on displacements is requested, a warning message to that effect is issued and the processing continues.

Example:$ print a report of displacement vectors on the databaseREPORT DISPS

A sample report is given below:

DISPLACEMENTS REPORT (AFTER COMBINE DISPS) ID LABEL SOURCE DATE TIME -- ----- ------ ---- ---- 3001 C001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55100000000 C001 TEST LOAD CASE + 10.50 PSI CABIN PRESSURE COMBINE DISPS FEB-09-2009 20:21.19100000000 C001 TEST LOAD CASE + 12.0 PSI COMBINE LOADS FEB-09-2009 20:21.23100000000 C001 TEST LOAD CASE + 4.0 PSI UPPER/10.5 PSI LOWER COMBINE DISPS FEB-09-2009 20:21.26 4001 D001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 7001 G001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 11001 K001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 13001 M001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 14001 N001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 15001 O001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 16001 P001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 1 P701 1.0 PSI CABIN PRESSURE LOAD FEB-09-2009 20:20.55 2 P702 1.0 PSI DECOMPRESSION PRESSURE LOAD FEB-09-2009 20:20.55 17001 Q001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 19001 S001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 20001 T001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55 21001 U001 TEST LOAD CASE LOAD FEB-09-2009 20:20.55

Data recovery

Description: Specfiy an XDB file to save results on

Command:

DEFINE XDB <file> [APPEND]

Action:

Three cases can be identified:

a. If XDB file does not exist then one is created

b. If XDB file exists and APPEND is specified then it is opened and results are appended to it

c. If XDB file exists and APPEND is not specified then a Fatal message is issued and processing is stopped

Example:$ Append results to XDBDEFINE XDB 'STRESS-LEFT WING' APPEND


12

Description: Define the set of elements or nodes for results recovery

Command:

DEFINE {SET|ESET} <file>

Action:

Create a node set (SET) or element set (ESET) based on the set defined in the given file (based on Nastran BDF format).

Example:$ specify the set of nodes for data recovery on left wingDEFINE SET '../sets/wings/left-wing.set'

Description: Define the set of results to be saved on XDB file

Command: DEFINE RESULTS <result items list>

Action:

This command defines the set of result types to be produced. If any of the result types are invalid, a Fatal message is issued and processing is stopped.

Example:$ Specify the set of results to be extractedDEFINE RESULTS FORCE, STRESS, GPFORCE, DISP, OLOAD

Description: Generate results related to load case given by LABEL

Command: RECOVER <LABEL>

Action:

This command will recover and store results based on the settings for the last

• DEFINE XDB and

• DEFINE SET|ESET, and

• DEFINE RESULTS

Note: • If a node SET is defined then some results such as stress cannot be recovered.

• If file does not exist then a Fatal message is issued and processing is stopped.


Commands. The above 3 commands are not considered cumulative. In other words, a new definition of an ESET will replace the last definition of SET|ESET, and the same with DEFINE RESULTS and DEFINE XDB.

Example:$ Recover results for test load caseRECOVER 'TEST LOAD CASE'$ Recover results for combined load case "test load + cabin pressure"RECOVER 'TEST LOAD CASE + CABIN PRESSURE'

Other Commands

Description: Specify an existing Nastran database to connect to

Command: DEFINE NDB <MASTER>

Action:

Restart from existing database. If this is not the first line in command script, then all queued operations are executed prior to the processing of this command.

Example:$ Connect to gear-up database of ultimate loadsDEFINE NDB '../gear-up/gu-ultimate'

Description: Instantiate a new Nastran database with given name (MASTER) and store model given in BDF file into the database.

Command: DEFINE NDB <MASTER> USING BULK <BDF>

Action:

This command indicates an initial run; therefore, a Fatal message is issued if MASTER exists or if BDF does not exist. If this is not the first line in command script, then all queued operations are executed prior to the processing of this command.

Example:$ Instantiate a Nastran database and load in the various parts of the model from 6 different $ bdf filesDEFINE NDB 'ULTIMATE_GUP' USING BULK

Note: If LABEL does not exist, a warning message to that effect will be issued and processing will continue.


14

'../../models/aft-floor.bdf''../../models/aft-floor-panels.bdf''../../models/flap-track.bdf''../../models/fwd-floor.bdf''../../models/fwd-floor-panels.bdf''../../models/horiz-stab.bdf'

15Loads ManagementLimitations

LimitationsThe beta release of this solution in MD Nastran 2010 will have limitations in the following areas:

Combine Loads & Combine Disps Requires that the databases being read are of the same version and that they are both MD Nastran 2010.

You cannot combine displacements or loads if one analysis was solved with an i4 version and one analysiswithan i8 version of MD Nastran .

You cannot combine displacements or loads if one analysis was done on Unix/Linux and one analysis was done on Windows.

Thermal LoadsThermal load cases cannot be currently handled in this solution.

Sequence DependenceThe high level commands described in previous sections, if appearing in the same command file should obey the following order:

• DEFINE NDB/XDB - Opens database

• DELETE LOADS - Delete existing loads

• DEFINE LOADS - Add new load vectors

• COMBINE LOADS - Combine load vectors

• DELETE DISPS - Delete existing displacements

• SOLVE LOADS - Add new displacement vectors

• COMBINE DISPS - Combine displacement vectors

• RECOVER - Recover results to XDB

Report requests can follow each of these command groups. So potentially there could be a total of 16 reports generated thru a command file-2 after each group of commands.

• REPORT LOADS

Loads Management User’s GuideLimitations

16

• REPORT DISPS

Load CombinationsLoads or solution vectors originating from different databases cannot be used in a COMBINE operation. COMBINE operations can only apply to loads and solution vectors that are on the same database.

SuperelementsSuperelements will not be supported in the MD Nastran 2010 release of this capability.

Note: 1. If commands are not in the given order then they will be grouped and processed in the above order. So if certain operations must be processed out of the given order, then the commands should be broken up into multiple files where within each file the order given above is acceptable.

2. In MD Nastran 2010, there are two commands that automatically trigger the splitting of the job-DEFINE NDB and DEFINE XDB. So if the application encounters one of these two commands in the middle of a command file, it will first process all commands that appear before it in the command file. It will then continue grouping and processing other commands until another such DEFINE command (or end of command file) is encountered.

17Loads ManagementExample Command Scripts

Example Command Scripts

Script1: Read in the model information and store on Nastran DB$ Instantiate a Nastran database and load in the various parts of the model from 6 $ different bdf filesDEFINE NDB 'ULTIMATE_GUP' USING BULK'../../models/aft-floor.bdf''../../models/aft-floor-panels.bdf''../../models/flap-track.bdf''../../models/fwd-floor.bdf''../../models/fwd-floor-panels.bdf''../../models/horiz-stab.bdf'

To run the script: ltool scriptFilename [old=yes/no] [Nastran keyword] [Nastran keyword 2], …

Example: ltool Script1 smaster=500000 sys19=0 mem=500M diag=8,15,9

Script 2: Add 3 load cases and solve them$ Connect to the existing Nastran databaseDEFINE NDB 'ULTIMATE_GUP'$ Add test load casesDEFINE LOAD 'TEST LOAD CASE 3001'

USING 3001FROM '../../loads/ultimate/gear_up/C001.load'$DEFINE LOAD 'TEST LOAD CASE 3002'USING 3002FROM '../../loads/ultimate/gear_up/C002.load'

$ Add cabin pressureDEFINE LOAD '1.0 PSI CABIN PRESSURE'USING 2001FROM '../../loads/pressure/P001.load'$$ Add decompression pressure from multiple files$DEFINE LOAD '1.0 PSI DECOMPRESSION PRESSURE'USING 1001FROM '../../loads/pressure/p700.frc''../../loads/pressure/p701.frc''../../loads/pressure/p702.frc'$$ Solve all load cases that were defined above$

Loads Management User’s GuideExample Command Scripts

18

SOLVE LOAD '1.0 PSI CABIN PRESSURE'SOLVE LOAD '1.0 PSI DECOMPRESSION PRESSURE'SOLVE LOAD 'TEST LOAD CASE 3001'

Script 3: Combine load cases and solve them$ Connect to the existing Nastran databaseDEFINE NDB 'ULTIMATE_GUP'$$ Combine loads from test load case 3001 and cabin pressure$COMBINE LOADS 'TEST LOAD CASE 3001 + CABIN PRESSURE'FROM 1.0 * 'TEST LOAD CASE 3001'

- 6.5 * '1.0 PSI CABIN PRESSURE'$$ Combine loads from test load case 3001, 3002 and decompression pressure$COMBINE LOADS 'TEST LOAD CASE 3001 + 3002 + DECOMP. PRESSURE'FROM 1.0 * 'TEST LOAD CASE 3001' + 2.0 * 'TEST LOAD CASE 3002' + 3.5 * '1.0 PSI DECOMPRESSION PRESSURE'$$ Solve all load cases that are combined here$SOLVE LOAD 'TEST LOAD CASE 3001 + CABIN PRESSURE'SOLVE LOAD 'TEST LOAD CASE 3001 + 3002 + DECOMP. PRESSURE'

Script 4: Combine displacements$ Connect to the existing Nastran databaseDEFINE NDB 'ULTIMATE_GUP'$$ combine displacement vectors to get displacements for $ test case 3002 + decompression pressure$COMBINE DISPS 'TEST LOAD CASE 3002 + DECOMP. PRESSURE'FROM 1.0 * 'TEST LOAD CASE 3001 + 3002 + DECOMP. PRESSURE' - 1.5 * 'TEST LOAD CASE 3001'

Script 5: Delete/combine loads/displacements and solve$ Connect to the existing Nastran databaseDEFINE NDB 'ULTIMATE_GUP'$$ Delete incorrect loads and displacements$DELETE LOAD 'TEST LOAD CASE 3001 + 3002 + DECOMP. PRESSURE'DELETE DISP 'TEST LOAD CASE 3001 + 3002 + DECOMP. PRESSURE'

19Loads ManagementExample Command Scripts

$$ Combine correctly this time$COMBINE LOADS 'TEST LOAD CASE 3001 + 3002 + DECOMP. PRESSURE'FROM 1.0 * 'TEST LOAD CASE 3001' + 2.0 * 'TEST LOAD CASE 3002' + 2.5 * '1.0 PSI DECOMPRESSION PRESSURE'$$ solve newly combined load case$SOLVE LOAD 'TEST LOAD CASE 3001 + 3002 + DECOMP. PRESSURE'$$ Correct the previously combined displacements$COMBINE DISPS 'TEST LOAD CASE 3002 + DECOMP. PRESSURE'FROM 1.0 * 'TEST LOAD CASE 3001 + 3002 + DECOMP. PRESSURE' - 1.5 * 'TEST LOAD CASE 3001'

Script 6: Recover results from 2 Nastran DBs and save results in an XDB $$ Open up the XDB file and set up for results recovery$DEFINE XDB 'section44.xdb'$$ specify the set of nodes for data recovery on section 44$DEFINE SET '../sets/section44.set'$$ Specify the set of results to be extracted$DEFINE RESULTS FORCE STRESS,DISP,SPCF,MPCF,GPFORCE,OLOAD$$ Connect to the gear up database for ultimate loads$DEFINE NDB '../gu/ULTIMATE_GUP'$$ Recover loads critical to section 44$RECOVER 'TEST LOAD CASE 3001'RECOVER 'TEST LOAD CASE 3002 + DECOMP. PRESSURE'RECOVER '1.0 PSI DECOMPRESSION PRESSURE'$$ PULL FROM THE GEAR-DOWN DATABASE$DEFINE NDB '../gd/ULTIMATE_GDN'$$ Recover loads critical to section 44$RECOVER 'TEST LOAD CASE 4001'RECOVER 'TEST LOAD CASE 4001 + 0.50 PSI CABIN PRESSURE'RECOVER 'TEST LOAD CASE 4002'

Loads Management User’s GuideExample Command Scripts

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RECOVER 'TEST LOAD CASE 4002 + 0.50 PSI CABIN PRESSURE'

Script 7: Recover results from a Nastran DBs and save results in 2 XDBs$ Connect to an existing Nastran DB$DEFINE NDB '../gu/ULTIMATE_GUP'$$ Specify the set of results to be extracted$DEFINE RESULTS FORCE STRESS,DISP,SPCF,MPCF,GPFORCE,OLOAD$$ Create an XDB for section 17$DEFINE XDB 'section17.xdb'DEFINE SET '../../sets/section17.sets'$$ Recover results for loads critical to section 17$RECOVER 'TEST LOAD CASE 3001'RECOVER 'TEST LOAD CASE 3002 + DECOMP. PRESSURE'RECOVER '1.0 PSI DECOMPRESSION PRESSURE'$$ Create an XDB for section 28$DEFINE XDB 'section28.xdb'DEFINE SET '../../sets/section28.sets'$$ Recover results for loads critical to section 28$RECOVER '1.0 PSI CABIN PRESSURE'RECOVER '1.0 PSI DECOMPRESSION PRESSURE'RECOVER 'TEST LOAD CASE 3001 + 3002 + DECOMP. PRESSURE'

MD Nastran 2010 Loads Management User's Guide (Pre-Release)

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