# AcuOptiStruct

AcuOptiStruct is an AcuSolve post-processing program used to generate an OptiStruct input deck for linear and non-linear thermal stress analysis for conjugate heat transfer problems using the AcuSolve database. In the current version, pressure loads (PLOAD), temperature loads (TEMP) and displacement and rotation single point constraints (SPC) are supported. This utility can be used for both steady and transient problems.

## Syntax

acuOptiStruct [options]

## Type

AcuSolve Post-Processing Program

## Description

In the following, the full name of each option is followed by its abbreviated name and its type. For a general description of option specifications, see Command Line Options and Configuration Files. See below for more individual option details:
help or h (boolean)
If set, the program prints a usage message and exits. The usage message includes all available options, their current values, and the place where each option is set.
problem or pb (string)
The name of the problem is specified via this option. This name is used to generate input file names and extracted surface file names.
working_directory or dir (string)
All internal files are stored in this directory. This directory does not need to be on the same file system as the user-supplied input files.
run_id or run (integer)
Number of the run for which the translation is requested. If run_id is set to 0, the last run in the working directory is assumed.
output_format or ofmt (enumerated)
standard
Writes the OptiStruct input deck in the standard format.
long
Writes the OptiStruct input deck in the long format.
solid_names or solids (string)
Comma-separated list of solid names.
young_modulus or young (string)
Comma-separated list of values of Young’s modulus for all the solids in the order in which they appear in the solids option.
poisson_ratio or poisson (string)
Comma-separated list of values of Poisson’s ratio for all the solids in the order in which they appear in the solids option.
thermal_expansion or thermal (string)
Comma-separated list of values of thermal expansion coefficient for all the solids in the order in which they appear in the solids option.
density or den (string)
Comma-separated list of values of density for all the solids in the order in which they appear in the solids option.
reference_temperature or reftemp (string)
spc_surfaces or spcsurfs (string)
Comma-separated list of names of different surfaces where single point constraint (SPC) needs to be applied.
spc_surfaces_dof or spcsurfsdof (string)
Comma-separated list of degrees of freedom for different surfaces in the order in which they appear in the spcsurfs option.
spc_surfaces_dof_values or spcsurfsdofvals (string)
Comma-separated list of values of degrees of freedom for different surfaces in the order in which they appear in the spcsurfsdof option.
spc_volumes or spcvols (string)
Comma-separated list of names of different volume sets where a single point constraint (SPC) needs to be applied.
spc_volumes_dof or spcvolsdof (string)
Comma-separated list of degrees of freedom for different volume sets in the order in which they appear in the spcvols option.
spc_volumes_dof_values or spcvolsdofvals (string)
Comma-separated list of values of degrees of freedom for different volume sets in the order in which they appear in the spcvolsdof option.
time_steps or ts (string)
Comma-separated list of time steps to be translated. The comma-separated fields have the general range format beg:end:inc, where :end:inc and :inc are optional. beg specifies the first time step in the range. It may be either a given time step, as specified by a number, the letter F (or f) requesting the first available time step, or the letter L (or l) requesting the last available time step. end is the last time step in the range. It may be either a time step number or L (or l) requesting the last available time step. If end is missing, the range is assumed to simply represent a single time step, that is, end=beg and inc=1. inc is the increment that ranges from beg to end. It may be either a number or the letter A (or a) requesting all available time steps in the range. If :inc is missing, it is assumed to be one. The range may also be specified by the single letter A (or a), requesting all available time steps. This is equivalent to F:L:A. time_steps is used only for nodal data and is ignored for time series data. Examples of time_steps include:
acuOptiStruct -ts 35
# step 35
acuOptiStruct -ts 35, 33, 37
# steps 33, 35, and 37
acuOptiStruct -ts 33:37:2
# steps 33, 35, and 37
acuOptiStruct -ts 35,33:37:2,37
# steps 33, 35, and 37
acuOptiStruct -ts 33:37
# all steps from 33 to 37
acuOptiStruct -ts L
# last available time step
acuOptiStruct -ts F:L:A
# all available steps
acuOptiStruct -ts A
# all available steps
ignore_missing_steps or imts (boolean)
If set, missing requested time steps are ignored. Otherwise, if the requested time step does not exist, the command issues an error message and exits.
analysis_type or type (enumerated)
The type of thermal stress analysis for which the OptiStruct input deck needs to be created.
ctnl
The analysis type will be set to continuous transient non-linear analysis.
tnl
The analysis type will be set to transient non-linear analysis.
tl
The analysis type will be set to transient linear analysis.
snl
The analysis type will be set to steady non-linear analysis.
sl
The analysis type will be set to steady linear analysis.
line_buff or lbuff (boolean)
Flush standard output after each line of output.
verbose or v (integer)
Set the verbose level for printing information to the screen. Each higher verbose level prints more information. If verbose is set to 0, or less, only warning and error messages are printed. If verbose is set to 1, basic processing information is printed in addition to warning and error messages. This level is recommended. verbose levels greater than one provide information useful only for debugging.

## Examples

acuOptiStruct -pb Manifold -solids Solid -spcsurfs Flange_bolts,Outlet_end -spcsurfsdof 123456,123456 -spcsurfsdofvals 0,0 -type sl -ts L

In the example shown above, the acuOptiStruct program is used to generate an input deck for a linear steady state analysis for the problem named ‘Manifold’. The OS input deck is generated for the solid named ‘Solid’ and the surfaces, Flange_bolts and Outlet_end are constrained in all the degrees of freedom (both translation and rotation in X, Y and Z directions with a value of 0). The data from the last time step is used in this example. Since the Young’s modulus, Poisson’s ratio and thermal expansion coefficient are not specified explicitly, the default values will be used.

For the same set of constraints as in the previous example, but a transient non-linear analysis, the following command should be given:

acuOptiStruct -pb Manifold -solids Solid -spcsurfs Flange_bolts,Outlet_end -spcsurfsdof 123456,123456 -spcsurfsdofvals 0,0 -type tnl -ts A

In this case, a transient non-linear analysis input deck will be created with nodal data at every available time step.

For problems involving multiple solids with different material properties, the Young’s modulus, Poisson’s ratio, thermal expansion coefficient and density values should be specified, and the order should be the same as how they appear in the solids option:

acuOptiStruct -pb brake_disc -solids solidName1,solidName2 -young 180e09,200e09 -poisson 0.30,0.265 -thermal 1.7e-5,1.8e-5 -den 7200, 7800 -spcsurfs Flange_bolts,Outlet_end -spcsurfsdof 123456,123456 -spcsurfsdofvals 0,0, -type sl -ts L

In the above example, the OptiStruct deck will be generated for the two solids ‘solidName1’ and ‘solidName2’ with the following material properties:
Table 1.
Young’s modulus (GPa) Poisson’s ratio Thermal expansion coefficient (1/K) Density (kg/m3)
solidName1 180 0.3 0.000017 7200
solidName2 200 0.265 0.000018 7800