1MSC.Patran 2003 Features and Capabilities

PARAMETRIC PARAMETRIC MODELINGMODELING

2MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELINGProvide automated parametric analysis in support of complex design processes

Allow users to parametrically investigate and assess a number ofdifferent designs via batch submittal of a number of different design studies

Permits the use of named variables to replace the usual fixed numerical values of the modeling parameters

The values of these parameters different than the prescribed default can be provided by an external file

Configuration file

Generate output file containing pertain analysis dataAssign result value to a variable for additional calculation & processing

The goal is to make it possible for the user to use names and default values for variables (parameters) in every entry point on every form that can be accessed for modeling purposes

3MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELINGA new toolbox implemented as an adaptive form accessed from the main menu bar and called “Parametric Modeling” has been developed

Variables definition modeDefine a variable name and its default value to be used during the modeling process

Response variables creation modeSearch through and manipulate the results of analysis to define meaningful metrics for export to an external file

4MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELINGVariable creation

5MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELINGMacro creation

6MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELINGResponsive variable creation

7MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELINGSteps in parametric modeling

1. Create variables/macros

2. Assign variables to specific Patran actions

3. Define desired results as output variables

4. Create and assign a configuration file

5. Run the session file containing variable settings and Patran actions

6. Iterate analysis process using data stored in the output file

8MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELINGConfiguration file format

The configuration file is used to reset existing Parametric Modeling variables to new values

The format of the configuration file is: name = value ! comment

Here are some examples.

maximum = 1000 ! this is an integer

three = 1, 2, 3 ! this is a 3 word integer array

data = 37.655 ! this is a real

moredata = 1.0, 2.0, 3.0, 4.0 ! this is a 4 word real array

name = mat1 ! this is a string variable, note no quotes

names = one, two, three ! this is a string array, again no quotes

Configuration filenames are case sensitive

9MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELING SCENARIOSUsing variables and configurations

Marco definitions and usage

Output definitions

10MSC.Patran 2003 Features and Capabilities

CASE STUDY: PARAMETRIC MODELINGModel a cylinder with a hole through itVary the cylinder radius and height

11MSC.Patran 2003 Features and Capabilities

CASE STUDY: PARAMETRIC MODELINGPart dimensions cyl_radius

cyl_height

6 * cyl_radius

cyl_height / 23 * cyl_radius

hole_radius

12MSC.Patran 2003 Features and Capabilities

CASE STUDY: PARAMETRIC MODELINGStep 1: Define variables

13MSC.Patran 2003 Features and Capabilities

CASE STUDY: PARAMETRIC MODELINGStep 1: Define variables

cyl_height = 60

cyl_radius = 10

hole_radius = 2

14MSC.Patran 2003 Features and Capabilities

CASE STUDY: PARAMETRIC MODELINGStep 2: Create a cylinder using the variables

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CASE STUDY: PARAMETRIC MODELINGCreate the cutter and subtract it from the cylinder

16MSC.Patran 2003 Features and Capabilities

CASE STUDY: PARAMETRIC MODELING

Step 3: Set up the configuration filesQuit Patran

Create relevant configuration file(s)

These files contains the new variable definitions.

my_config_1.dat

my_config_2.dat

my_config_3.dat

cyl_height = 55

cyl_radius = 15

hole_radius = 2

cyl_height = 45

cyl_radius = 25

hole_radius = 2

cyl_height = 50

cyl_radius = 20

hole_radius = 2

17MSC.Patran 2003 Features and Capabilities

CASE STUDY: PARAMETRIC MODELINGStep 4: Run the session file created earlier

Assign the configuration file using an environment variable:

parametric_modeling_config_file

Or assign the configuration file using the following command:

In the command line

In the session file

parametric_modeling_util.define_user_config_file (“my_config_1.dat”)

When the session file is played, Patran looks for the variable definitions contained in the configuration file

By creating/editing the configuration file and re-playing the session file, the parametric modeling process is automated

The parametric process can be executed in batch

Patran –spf <session file name> -b

18MSC.Patran 2003 Features and Capabilities

CASE STUDY: PARAMETRIC MODELING

Step 4: Run the session file created earlier

Vary the cylinder height

Vary the cylinder height & radius

19MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELING SCENARIOSUsing variables and configurations

Marco definitions and usage

Output definitions

20MSC.Patran 2003 Features and Capabilities

CASE STUDY: DESIGN EXPLORATIONCANTILEVER BEAM

Structural analysis of a cantilever beamDistributed loads of 1500 lbsFixed endVary the beam cross section

HeightWidth

21MSC.Patran 2003 Features and Capabilities

CASE STUDY: CANTILEVER BEAMStep 1: Define variables

Width = 2

Height = 4

Length = 50

Element_size_length = 2

element size along the beam

Element_size_section = 1

element size @ cross section

22MSC.Patran 2003 Features and Capabilities

CASE STUDY: CANTILEVER BEAMStep 2: Define macros

Pressure_loading

1500 / area

Area = length * width

Mesh_seed_length

Length / Element_size_length

Convert the result into an integer value

Mesh_seed_width

Width / Element_size_section

Convert the result into an integer value

Mesh_seed_height

Height / Element_size_section

Convert the result into an integer value

23MSC.Patran 2003 Features and Capabilities

CASE STUDY: CANTILEVER BEAMStep 3: Create the initial geometry

Create the 4 x 2 x 50 solid

Use variables

`length`

`width`

`height`

24MSC.Patran 2003 Features and Capabilities

CASE STUDY: CANTILEVER BEAMStep 4: Define mesh seeds & generate mesh

Use macros to define mesh seeds

`mesh_seed_length()`

`mesh_seed_width()`

`mesh_seed_height()`

Generate hex8 elements

25MSC.Patran 2003 Features and Capabilities

CASE STUDY: CANTILEVER BEAMStep 5: Define loads and boundary conditions

Use macro to define the pressure loading

`pressure_loading`

26MSC.Patran 2003 Features and Capabilities

CASE STUDY: CANTILEVER BEAM

Step 6: Set up the configuration fileQuit Patran

Create relevant configuration file:

Height = 3

Width = 3

Length = 50

Run the session file

Model has been revised

Pressure loading is updated accordingly

Top surface area was 100

Top surface area is now 150

my_config.dat

height = 3

width = 3

length = 50

27MSC.Patran 2003 Features and Capabilities

PARAMETRIC MODELING SCENARIOSUsing variables and configurations

Marco definitions and usage

Output definitions

28MSC.Patran 2003 Features and Capabilities

CASE STUDY: ANALYSIS ITERATIONCANTILEVER BEAM

Constant distributed loads of 1500 lbsInitial cross section of 3 x 3Examine 2 analysis criteria

Maximum displacement at free endMaximum bendinf stress at fixed end

Vary the beam cross section to 4 x 2Reexamine the analysis criteria

29MSC.Patran 2003 Features and Capabilities

CASE STUDY: ANALYSIS ITERATIONStep 1: Define output variable

Maximum displacement at free end

Use variables

Output type = Nodal Vector

Quantity = Y Component

Target = Nodes at the free end

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CASE STUDY: ANALYSIS ITERATIONStep 2: Define output variable

Maximum bending stress at fixed end

Use variables

Output type = Element Tensor

Location = At Node

Quantity = Y Component

Target = Elements at the fixed end

31MSC.Patran 2003 Features and Capabilities

CASE STUDY: PARAMETRIC MODELINGStep 3: Run the session file created earlier

In addition to the configuration file environment variables or PCL commands

The following environment variables or PCL commands are needed to generate the external output file

Parametric_modeling_util.print_all_output()Enable the printing of output variables if the output file is already defined

Assign the output file using an environment variable:

parametric_modeling_output_fileOr assign the configuration file using the following command:

In the command line

In the session file

parametric_modeling_util.define_user_output_file (“my_output.dat”)

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CASE STUDY: ANALYSIS ITERATIONStep 4: Perform initial analysis

my_config.dat

height = 3

width = 3

length = 50

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CASE STUDY: ANALYSIS ITERATIONStep 5: Examine output file

!

! VARIABLES

!

Real length = 50 !

Real width = 3 !

Real height = 3 !

Real element_size_length = 2 !

Real element_size_section = 1 !

!

! MACROS

!

area() = 150. ! Top surface area

pressure_loading() = 10

mesh_seed_length() = 25.

mesh_seed_width() = 3.

mesh_seed_height() = 3.

!

! OUTPUTS

!

Real max_displacement = -1.084347E-3 ---> At Node 2 ! maximum displacement at free end

Real Max_stress = 8.131680E+3 ---> At Element 51 ! Maximum bending stress

Output variables & results

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CASE STUDY: ANALYSIS ITERATIONStep 6: Iterate analysis process

New configuration file

my_config_1.dat

height = 4

width = 2

length = 50

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CASE STUDY: ANALYSIS ITERATIONStep 7: Examine output file

!

! VARIABLES

!

Real length = 50 !

Real width = 2 !

Real height = 4 !

Real element_size_length = 2 !

Real element_size_section = 1 !

!

! MACROS

!

area() = 100. ! Top surface area

pressure_loading() = 15

mesh_seed_length() = 25.

mesh_seed_width() = 2.

mesh_seed_height() = 4.

!

! OUTPUTS

!

Real max_displacement = -8.418538E-4---> At Node 2 ! maximum displacement at free end

Real Max_stress = 6.930413E+3---> At Element 76 ! Maximum bending stress

Output variables w/ new results

Automatic update of macro values

36MSC.Patran 2003 Features and Capabilities