What's New

View new features for OptiStruct 2023.1.

Altair OptiStruct 2023.1 Release Notes

Highlights

  • Brittle damage
  • Truss layout optimization
  • Johnson-Holmquist material
  • Material for concrete, soil, and geomechanics
    • Mohr-Coulomb material
    • Drucker-Prager material
  • Kinematic and mixed hardening for LGDISP shells
  • Encrypt entire INCLUDE files
  • Neuber stress response for topology and free-size optimization

New Features

Stiffness, Strength and Stability
MATMDS with INISTRS
Initial stress (INISTRS) is now supported for elements referencing MATMDS material (interfacing with Altair MultiScale Designer).
Mohr-Coulomb Plasticity model
The Mohr-Coulomb Plasticity model is now available for implicit nonlinear analysis. This can be activated using the MC continuation line on the MATS1 Bulk Data Entry. The COHE field is used to define cohesion, the FRICA field defines the friction angle, and DILA can be used to define the dilatancy angle. This is supported for nonlinear static and nonlinear transient for both small and large displacement analysis. It is only supported for solid elements. Temperature dependency is not currently supported.
Drucker-Prager Plasticity model
The Drucker-Prager Plasticity Model is now available for implicit nonlinear analysis. This can be activated using the DP continuation line on the MATS1 Bulk Data Entry. The YIELD field defines the initial yield strength of the material, which is used to calculate the cohesion value. The TYPE field determines how the cohesion value is calculated; it can be set to COMP (compression), TENS (tension), or COHE (cohesion). Based on the value of the TYPE field, the corresponding approach is used to calculate the cohesion value using the YIELD strength. The FRICA field defines the friction angle, and DILA can be used to define the dilatancy angle. This is supported for nonlinear static and nonlinear transient for both small and large displacement analysis. It is only supported for solid elements. Temperature dependency is currently not supported.
GPSTRESS support for FAILURE output
A new location option called GPS is available on the FAILURE I/O Option. This allows the grid point stress values to be used to calculate the failure output. This is different from using the CORNER location; for GPS, the stresses are first averaged at each grid before being used for failure calculation.
Kinematic and mixed hardening for LGDISP for shells

Kinematic hardening (HR=2) and mixed hardening (HR=3) on the MATS1 Bulk Data Entry are now supported for shell elements in large displacement nonlinear analysis.

Rayleigh damping for MCOHED in linear transient analysis
Rayleigh damping via the ALPHA field on the RAYL continuation line is now supported for the MCOHED cohesive material in linear transient analysis.
Alternate formulation for CSHEAR
An alternate formulation for CSHEAR elements is now available and can be activated via PARAM,SHEARALT,YES. This formulation can improve results when shear panels are distorted and enhance stress results in free thermal expansion.
JOINTG elastic force output in .joint format
Elastic forces are now output for JOINTG elements in the .joint file (OPTI format).
Buckling analysis under inertia relief
Buckling analysis under inertia relief is now available. PARAM,INRELBCK,1 can be used to allow buckling analysis under inertia relief, and SUPORT degrees of freedom from inertia relief are used for buckling analysis.
Initial plastic strain input
Initial plastic strain input is now available via the INIPS Bulk Data Entry and Subcase Information Entry. With INIPS, you can directly input the initial plastic strain or reference an external H3D file which contains the initial plastic strain to be applied. The IPSADD Bulk Data Entry is also available to combine multiple INIPS Bulk Data Entries.
Explicit Dynamic Analysis
Brittle damage
Brittle material damage definition is now available via the MATBRT Bulk Data Entry for explicit analysis. The tensile and shear crack modes are available. For the tensile crack mode, the STRN option allows crack opening to be expressed as principal stress versus crack opening strain, DISP option for principal stress versus crack opening displacement, and ENER option for crack opening in the form of principal stress and fracture energy.
For shear crack mode, the RFAC option allows the crack opening to be expressed in the form of retention factor versus crack opening strain/displacement, while the PLAW option allows the crack opening to be expressed in the form of power law factor and maximal crack opening strain/displacement. The FAILURE flag is also available to control element deletion.
Johnson-Holmquist material
Johnson-Holmquist material is now available to model brittle material behavior for explicit analysis. It can be activated using the JHOLMQ continuation line on the MATS1 Bulk Data Entry. This is currently only supported for solid elements.
Component-based mass table in .out file
HyperMesh component-based mass table is now printed in the .out file as part of the printing from OUTPUT,MASSCOMP for explicit analysis. The component ID, mass, added Mass, and component name are available in this table.
TLOAD2 support
TLOAD2 load input is now supported for explicit analysis.
Default integration scheme for CHEXA8 in explicit analysis switched to URI
The default integration scheme for CHEXA8 elements in explicit analysis has now been switched from AURI (Average Uniform Reduced Integration) to URI (Uniform Reduced Integration).
Noise and Vibration
Vector-based filtering for threshold-based stress output in transient, steady-state, FRF, and random
Vector-based filtering is now available for threshold options to filter stress output. The VFLTR keyword should added to the STRESS output request along with one of the filtering options, THRESH, RTHRESH, TOP or RTOP. For elements which satisfy the filtering threshold condition at any time-step or frequency, they are output for the full time or frequency domain. This is currently supported for transient, steady-state, frequency response, and random response analysis.
ACPOWER and ACINT support for APML
Acoustic Power (ACPOWER) and Acoustic Intensity (ACINT) are now supported for Adaptive Perfectly Matched Layer (APML) acoustic analysis. Sound pressure output was made available in previous releases for APML.
GPSTRESS output for random response
Grid point stress results are now supported for random response analysis.
CONTACT support for internal superlements
CONTACT is now supported for internal superelements. The contact can be a part of either the superelement or the residual part of the model.
Ignore frequency-dependent material MATF# using PARAM,MATFREQ,OFF
Frequency-dependent material defined via MATF# entries can be ignored from the run by setting PARAM,MATFREQ,OFF.
Alternate method to improve performance for modal FRF with frequency-dependent materials (AMSFRMAT)
An alternate method is available via PARAM,AMSFRMAT,YES for modal frequency response solutions when a large number of frequency-dependent materials (> 1000 dof) are present and AMSES is used as the eigensolver. This alternate method can help improve the performance of the modal frequency response solution.
Total time length for steady state analysis
The total time length for steady state analysis can now be defined via the TTIME field on the STEADY Bulk Data Entry. The default is 1.0 divided by the minimum loading frequency used for the steady state analysis.
Additional output support for steady state analysis
The pressure output (including mic pressure for IE and APML) and element force output are now supported for steady state analysis. The displacement, stress, and ERP results are already supported for steady-state analysis.
Enhanced support for stress output in random response
The stress output for random response analysis has been enhanced with the following grouping:
STRESS(PSDM) → only PSDM related output
STRESS(RMS) → only RMS output
STRESS(OPSDF) → only PSD output
STRESS(PSDF) → PSD, RMS, and PSDM output
STRESS(PSDFC) → PSD, RMS, PSDM, and cumulative RMS output
Fatigue
Back-calculation for fatigue analysis
Back-calculation for fatigue to calculate scaling factor for a particular target life is now supported and can be activated by requesting FOS output, followed by setting target life in the TGLIFE field of the FOS continuation line on FATPARM Bulk Data Entry. The METHOD field should be set to SCALE for back calculation. The results are supported in the H3D and OPTI formats.
Cyclic stress standard error (SEc) in EN fatigue
The standard error of cyclic stress-strain curve is now supported via the SEc field in the EN material section of the MATFAT Bulk Data Entry. The value of SEc is used to modify the cyclic strength coefficient (K’).
Critical plane support in fatigue
The CRTPLN option can be specified for the COMBINE field to activate critical plane approach for random response (SN & EN), sine-sweep (SN & EN), sine-sweep on random, sine on random, multiple sine tones (SN), and transient (SN & EN) fatigue analysis.
Heat Transfer Analysis
OUTPUT,MATRIX support for linear transient heat transfer
The heat capacity matrix, the conductivity matrix, and the convection matrix are now available in the corresponding *_full.mat file. Options such as dense or sparse matrix output and user-defined precision are available.
Optimization
Truss layout optimization
With truss layout optimization, you can find the optimal truss-based layout for a given design space. It is useful for applications where structures include trusses (for example, architectural industry for building design). The truss layout optimization is activated by the DTRUSS Bulk Data Entry. It also contains the parameters to control the optimization run, such as permissible stress bounds for the truss elements, truss cross-sectional area limits, symmetry and buckling constraints. Currently the presence of the DTRUSS entry implies the entire model is part of the design space. This is supported for shell and solid elements and for linear static analysis.
Note: The trusses are represented by CROD elements for truss layout optimization.
Electro-thermal responses for optimization
Thermal compliance (RTYPE=TCOMP on DRESP1) and temperature (RTYPE=TEMP) responses are supported for electro-thermal analysis. Joule heating is taken into account in sensitivity analysis. Topology, free-size, size, free-shape, shape, and topography optimization are supported.
Overhang constraint support in level set optimization
Overhang constraints are now supported in level set optimization.
MAXDIM and MINGAP are now supported in level set optimization
MAXDIM and MINGAP are now supported in level set optimization. MINGAP should not be set larger than MAXDIM for level set.
NORM-based response sensitivity output added to OUTPUT,ASCSENS
Sensitivity output for NORM-based responses are now available in the *.asens file when OUTPUT,ASCSENS is requested.
Neuber stress response for topology and free-size optimization
Neuber stress responses are now supported for topology and free-size optimization. Shell and solid elements are supported. The stress-norm approach is used.
General
Encrypt entire INCLUDE files
An alternate encryption tool is now available to encrypt entire include files. This allows for a more versatile and easy-to-use method to encrypt data in the OptiStruct model. The entries currently supported for encryption are properties, materials, and their associated tables. Once the new encryption tool is used to create an encrypted version of an include file, the encrypted include file can be shared with other users and it can be directly included in the base model (similar to how the unencrypted include file was included). OptiStruct completes the run without any additional user-input.
Recovery of results on internal SE part
The MODEL card is now supported for internal superelements. Results can now be recovered for the internal superelement part. Additionally, an SEDR entry can be used to define the superelement parts for which results should be recovered.
On-the-fly output enhancements
The following are now supported for On-the-fly output:
  • VON mises stress option for 1D
  • Plastic strain for implicit
  • Factor of safety (FAILURE)
  • CBUSH element force
SET creation with Cylindrical bounding box
A GRID SET can now be created by identifying a cylindrical bounding box and all grids present within the bounding box are a part of this SET. The SUBTYPE should be set to BBOXC and center grid points of each circular side of the cylinder are specified via G1/Xi,Yi,Zi and G2/Xj,Yj,Zj. The RADIUS field is used to define the radius of the cylinder.
Statistics output for Neuber stress
Statistics output, which includes maximum, time of maximum, arithmetic mean, RMS, variance, and standard deviation are now supported for Neuber stresses.
RIGID-based grid SET
A GRID SET can now be created by using the SUBTYPE=RGTYPE and then the available options can be set to RBAR, RROD, RBE1, RBE2, RBE3, RSPLINE, RSSCON, RJOINT, and RBODY. These options can be specified individually or in combination with each other. An additional option ALL is available to choose all rigid elements for inclusion in the GRID set.
Neuber stress/strain output at both Z1 and Z2 for shells
Neuber stress and strain are now output at both Z1 and Z2 sides of shells.
Element strain output support in OP2 and PUNCH for normal modes analysis
Element strains are now output in OP2 and PUNCH formats for normal modes analysis.
LDM and multi-level DDM no longer supported for nonlinear analysis
Load-decomposition method (LDM) and multi-level DDM are no longer supported for nonlinear analysis. Domain decomposition method (DDM) is still supported for nonlinear analysis and can significantly improve performance.
Store user data on MAT1 material
User material data can now be stored on the UDATA continuation line. The data can be stored in pairs, with each parameter associated with its name followed by its value.
Intel MPI version upgraded from 2021.2 to 2021.10
The Intel MPI version has been upgraded from 2021.2 to 2021.10.
Missing DMIG ERRORs can now be switched to WARNING
ERRORs when DMIGs matrices referenced in the subcase section are not present can now be converted to WARNINGs with SYSSETTING(UNREFSID=WARN).
Enhanced RBE3 formulation for nonlinear LGDISP analysis
The RBE3 formulation is enhanced for nonlinear LGDISP analysis and shows improved handling of RBE3s with released independent translational degrees of freedom.
Clear flags for continuation lines on TSTEP Bulk Data Entry
The time integration continuation line now has a clear flag, TINT, to identify the beginning of input parameters for time integration. Similarly, the TSTEP flag now indicates the beginning of input parameters for time-stepping. This allows for easier handling during import/export in HyperMesh and also for manually entering data on the TSTEP entry. Therefore, the fields in the new format are offset to the right but one field.
Note: The old format without these new flags is still accepted by OptiStruct.
Add Comments in the Bulk Data section of the input file
Comments can now be added in the Bulk Data section of the input file using the COMMENT ON/OFF Bulk Data Entries. Any Bulk Data Entry lines between COMMENT ON and COMMENT OFF are excluded from the analysis.
Quick and simplified model summary in .json file
A quick and simplified model summary is available in a separate <filename>_summary.json file when using the -summary run option. The .json file contains an overall summary of all major entities in the model (such as number of grids, elements, properties, materials, and so on). It also contains subset summaries for each entity accordingly (such as an elements summary which contains the breakdown of number of elements of each type). This can provide some quick information which can be used to plan the required resources for the job (such as required memory, disk space, number of cores, and so on).
SYSSETTING to issue an Error when the sum of material damping is negative for an element
If SYSETTING(NEGGEERR=YES) is set, an error is now issued when the sum of material damping contributions for any element is negative. The damping contributions which are considered for calculating the sum are: damping from NSGE, GE on MATi data, and PARAM,G. Note that the GE damping on frequency-dependent material is also considered for the calculation.
Combined 2D and 3D stress/strain output in H3D for Von Mises or Maximum Principal
The stress and strain results for both 2D and 3D elements are now combined for easier visualization when Von Mises or Maximum Principal results are requested.

Resolved Issues

  • The algorithm for automatically handling the normals for panels in ERP has been enhanced to properly handle panels that contain ribs or similar features.
  • OptiStruct runs using Compose on Windows no longer fail due to missing library error.
  • A programming error is no longer issued when GM method is used for CMS generation, AUTOSPC is turned off, and zero-stiffness degrees of freedom are used for interface degrees of freedom (ASET/BSET). A clear error message is now issued that there is no stiffness associated with the interface degree of freedom for GM method.
  • Some high contact pressure is no longer localized at particular locations in the model due to improvements to continuous sliding (CONSLI) contact search.
  • A programming error is no longer issued when the model contains NSM with PARAM,INREL,-2, static subcases, and damping.
  • A programming error is no longer issued when Topography optimization with ERP responses is run with FREQ3 entry.
  • A clear error message is now printed when GE is not defined on PCOMPG during SE reduction and K42GG is specified in residual run to use damping matrix.
  • Material parameters printed in .prop and .h3d files are now consistent with the .out file for size optimization.
  • Licenses are now returned when an OptiStruct job is paused using the ACC pause button or using the <filename>.ossleep file. Once the job is resumed, the licenses are requested again.
  • A crash no longer occurs in RESFRC module when an NLSTAT analysis with both MATMDS and MATS1 in the model.
  • Rigid elements (RBE2 and RBE3) are now properly removed in the *_impl.h3d file when they are excluded via MODCHG. This has now been fixed.
  • When RBE3 elements are removed with MODCHG for NLSTAT analysis, the RBE3 elements are now properly removed from inside the analysis along with being removed from the regular H3D file. Previously, unexpected results occurred similar to those seen if the RBE3 element continued to exist.
  • A programming error no longer occurs when optimization with component-level mode tracking with AMSES is conducted for a model.
  • Non-converged results based on incremental NLOUT output for Nonlinear analysis are now properly written to the H3D file.
  • A programming error for shape optimization, which occurred when the run had an increase in the non-zero degrees of freedom from one iteration to the next and led to memory expansion beyond the available memory, no longer occurs.
  • NEUBB stress response no longer ignores the Z2 side of the shell during optimization.
  • A programming error no longer occurs when TEMP load is applied in transient analysis with SPCFORCE output request.
  • A programming error no longer occurs when CFAILURE output is requested for MAT9OR referencing PSOLID elements.
  • A crash no longer occurs when modal frequency response analysis with pretension is run for rotor dynamic analysis.

Altair OptiStruct 2023 Release Notes

Highlights

  • Axisymmetry with torsion loading
  • Plasticity for beams
  • Direct reading of the RSP file for transient analysis
  • Milling manufacturing constraints
  • Optimization for electrical analysis
  • Mode tracking with a SET of elements

New Features

Stiffness, Strength, and Stability
Axisymmetry allowing torsion about the axis-of-symmetry
New general axisymmetric elements are now available which allow torsion loads about the axis of symmetry. The Quadrilateral general axisymmetric element (CQAXIG) and Triangular general axisymmetric element (CTAXIG) are now available for circumferential deformation. When compared to the 2D axisymmetric elements CQAXI and CTAXI, which have two degrees of freedom at each node, the general axisymmetric elements have an additional degree of freedom at each node circumferentially and can have torsional deformation about the axis of symmetry. The properties for general axisymmetric elements can be defined using PAXIG. If PARAM,AXI2DTOR,YES is present, 2D axisymmetric elements CQAXI and CTAXI are considered as general axisymmetric elements CQAXIG and CTAXIG (PAXI is considered as PAXIG).
Linear extrapolation for small displacement nonlinear analysis
Linear extrapolation via EXTRA=LINEAR on NLADAPT and NLCTRL Bulk Data Entries is now supported for both small and large displacement nonlinear analysis.
New JOINTG joint types
Three new JOINTG types are now available: The PCART (Projection cartesian joint), PFLTR (Projection flexion joint), and BUSHING (Bushing joint, which is a combination of PCART and PFLTR joints). These are supported for multiple JOINTG characteristics such as Motion, Stop/Lock, Elasticity, and so on. For more information, see the JOINTG Bulk Data Entry documentation.
JOINTG elastic force output
JOINTG elastic forces are now output in addition to the JOINTG forces (total joint forces) for nonlinear stiffness JOINTGs.
Contact wear output
Contact wear and contact wear loss volume outputs are now available. The WEAR continuation line on the CONTACT Bulk Data Entry is used to define the contact wear properties for output. The wear properties include wear coefficient (KWEAR), secondary side material hardness (HARDNESS), exponent on pressure in Archard wear equation (A), and exponent on sliding velocity in Archard wear equation (B). Contact WEAR output is included when the CONTF I/O Option is specified in the model.
Rayleigh damping support for JOINTG
JOINTG now supports Rayleigh damping. This can be activated by specifying PARAM,ALPHA2 to add the corresponding viscous damping to the JOINTG elements in the model.
Explicit Dynamic Analysis
Energy output in THIST file by component, property, or set of elements
Time history energy output for explicit analysis is now available by component, property, or set of elements. This is controlled by setting the ENTRY field to COMP, PROP, or ESET on the THIST Bulk Data Entry. COMP outputs the requested time history output for all components, PROP outputs the requested time history output for all properties, and ESET outputs the requested time history output for the specified element set ID. The ID is of a SET which contains a list of element SETs with Boolean OR.
Fully integrated shells
A new element formulation type is available for shell elements in explicit analysis, in addition to the existing Belytschko-Tsay (BT) and Belytschko-Wong-Chang (BWC) types. To activate fully integrated assumed strain shell element formulation, set the ISOPE field to FULL on the PSHELL Bulk Data Entry.
Slipring
Slipring joint on JOINTG is now available for explicit analysis. Set up the slipring joint by defining the JTYPE field as SLIPRING on the JOINTG Bulk Data Entry.
Noise and Vibration
MFLUID wet surface coarsening
The COARSE option is now available to scale the mesh size of the internally generated MFLUID surface mesh. Coarsening the MFLUID surface mesh can help improve the performance and reduce memory and disk usage. The Mesh Size Factor (MSF) scales the average mesh size of the input MFLUID surface mesh. The new coarsened mesh is generated internally by a lightweight SimLab mesher included in the HyperWorks Solvers installation. No additional user input is required for this.
PEAKOUT support for PFPATH
PEAKOUT is now supported in the PFPATH I/O Option. If PEAKOUT is present, the filtered frequencies from the PEAKOUT data are considered for output of transfer path analysis.
ERP, CMSE/CMKE/CMDE, MODALSE/MODALKE/MODALDE support in PEAKOUT Bulk Data Entry
The result type used for peak identification on the PEAKOUT Bulk Data Entry now also includes support for ERP, CMSE, CMKE, CMDE, MODALSE, MODALKE, and MODALDE. If ERP is defined, the PANEL continuation line can be used to identify the Panel or Grid ID for the ERP response. If CMSE, CMKE, CMDE, MODALSE, MODALKE, or MODALDE are defined, the MODE continuation line can be used to identify the Superelement or Mode for output to be used for PEAKOUT filtering.
Dynamic stiffness output
Dynamic stiffness output is now supported via the KDYN output request. It is calculated as the reciprocal of the displacement. It is currently supported for frequency response analysis and is available in H3D and Punch formats.
DDM support for preloaded CCMS analysis
DDM is now supported when Component Mode Synthesis (CMS) reduction subcase contains a preload from linear static or nonlinear static analysis. One of the important use cases is using DDM for CMS reduction of a large model where the preloading comes from nonlinear static analysis.
Heat Transfer Analysis
Auto-time step
Automatic Time-stepping is now supported for both Linear and Nonlinear Heat Transfer analysis using the reference temperature method. It is not turned on by default, and can be activated by setting the MFREF field to 1 on the TSTEP Bulk Data Entry.
Repeated thermal cycle
One Step Transient Thermal Stress setup (OSTTS) can now be setup with repeated thermal cycles in structural load steps. The HST field on the TEMPT Bulk Data Entry can now be set to MHSUB to indicate the thermal load is read from multiple transient heat transfer subcases. The HSUB parameter references the identification number of a transient heat transfer subcase. The REPEAT parameter identifies the number of repeated cycles of temperature history from the specified transient heat transfer subcase, to be applied within the specified time period. The TEND parameter is available to define the end time of the period that the thermal load is applied.
Optimization
Milling constraints
The MILL continuation line on the DTPL Bulk Data Entry is now available to define milling constraints for topology optimization. There are two ways to define milling constraints: using the access angle (ANGLE), or using the bit and clamp dimensions (R, B, and H). The access angle (ANGLE) is defined as the ratio of radius of the outer circle to the depth of the milled hole. R is the radius of the mill bit, B is the length of the mill bit, and H is the radius of the mill head. Obstacles which define non-designable properties can be defined using the OBST continuation line.
Mode tracking for set of elements
Additional control for Mode tracking in optimization with eigenvalue analysis is now available via the new MODTRAK Bulk Data Entry. The MODTRAK Subcase Information Entry should be used to reference the MODTRAK Bulk Data Entry. The MODTRAK Bulk Data Entry also contains the TRAKSET field to define an Element SET ID to define a specific part of a model for mode tracking. This enables component-level mode tracking.
Electrical analysis
Optimization is now supported for electrical analysis. The Topology, Shape, Free-shape, Size, and Free-Size optimization design variables are supported. Two responses are currently supported. The Nodal Electric Potential response can be activated by setting the RTYPE field to ELPOT on the DRESP1 Bulk Data Entry. The GRID ID can be defined on the ATTi field. The Global Electric Compliance response can be activated by setting the RTYPE field to ELCOMP on the DRESP1 Bulk Data Entry. DRESP2 and DRESP3 Bulk Data Entries are also supported. Optimization for electrical analysis is supported for all element types and is currently only supported for linear steady-state electrical conduction analysis. Temperature dependency and electro-thermal coupling are not currently supported.
Include nominal design in DGLOBAL
New options is added on the DGLOBAL Bulk Data Entry to include the nominal design in the starting points. This option can be specified in the eighth field as YES/NO, with NO as the default option. When the mode tracking is used for DGLBOAL optimization and the nominal design is used as starting points, the modes calculated with nominal design are used as reference modes for mode tracking in any subsequent optimization with different starting points.
General
OLOAD output in FORCE/MOMENT Bulk format
New BULK and LOADID options are now supported for OLOAD output for FORCE and MOMENT outputs. If the BULK option is present in the OLOAD output request, the FORCE and MOMENT loads are written to a new ASCII file named filename.loadbulk. If LOADID=<ID> is defined in the same OLOAD request, the printed FORCE/MOMENT ID in the filename.loadbulk file is based on this ID as follows:
  • If LOADID=<ID> is defined, the ID of FORCE/MOMENT entries in the filename.loadbulk file is equal to ID from LOADID + Load ID of the subcase (the Load ID of the subcase is the ID referenced by the LOAD entry in the subcase).
  • If LOADID is not defined, the ID of FORCE/MOMENT entries is equal to the Load ID of the subcase (referenced by LOAD entry in the subcase).
RSP/RPC files as loading for transient analysis
The RSP file can now be used as loading and OptiStruct internally sets up the transient loading. The ASSIGN,EXTLOD entry can be used to identify the RSP or RPC file and mapping CSV file for the external loading. Additionally, the ID of the ASSIGN entry can then be referenced on a TLOAD1 entry in the transient analysis setup in the EXCITEID field. The TLOAD1 entry should have the TYPE field set to EXT to indicate the load is coming from an external file. Both direct and modal transient analyses are supported. The DELAY field on the TLOAD1 entry is supported for external loading (negative delay can be used to skip data in the RSP or RPC file which are not necessary).
Example:
ASSIGN,EXTLOD,102,’load.rsp’,’mapping.csv’
…
SUBCASE 1
…
BEGIN BULK
…
TLOAD1,13,102,,EXT
Plasticity for beam
The integrated beam formulation is now available for TYPE=ROD and TYPE=BAR for both implicit and explicit analysis. In this case, the beam is computed using cross-section integration. The integration points are automatically distributed in the section according to the quadrature order and the type of the section. The Quadrature order can be controlled using the Q_ORDER field on the INT continuation line in the PBEAML Bulk Data Entry.
ERP output support for transient analysis and steady subcase type
ERP output is now supported for transient analysis and steady-state analysis. For steady-state analysis, the currently supported outputs are displacement, stress, and ERP.
Stress/strain for random response in OPTI format
Stress and strain results are now available in OPTI format for random response analysis.
Transient results in OPTI format
OPTI format output is now supported for transient analysis, and the following outputs are supported: Displacement, Acceleration, Velocity, Stress, Strain, and Force.
PUNCH output by subcase
OUTPUT,PUNCH,BYSUB is now supported for all analysis types for which PUNCH output is supported. A filename_s#.pch file is output for each subcase where # is the subcase ID. Additionally, POST,TOFILE is now supported for additional analysis types. When both OUTPUT,PUNCH,BYSUB and POST,TOFILE are defined, POST,TOFILE takes precedence (wherein multiple subcases can be output in a single punch file if they have the same POST,TOFILE defined).
Reduced loading output in op4 file with PARAM,EXTOUT,DMIGOP4
Loading can now be reduced in the OP4 file using PARAM,EXTOUT,DMIGOP4 along with CMSMETH and the loading from the DMIG can then be used in the residual run with P2GLOAD.
Automatically adjusted grid coordinate for CBUSH to make non-zero length CBUSH
SYSSETTING (ZEROLBUSH=value) has been added for this release. If the length of CBUSH is less than the value, the coordinate of GB on CBUSH is replaced by the coordinate of GA.

Resolved Issues

  • Temperature results during a nonlinear heat transfer analysis with temperature-dependent specific heat no longer show an issue.
  • Strain energy results (ESE) are now correct when used together with PEAKOUT.
  • Strain energy of superelement/DMIG (CMSE) are now correct if DMIG is generated with CBN method.
  • Error #6114 now occurs correctly to indicate that a section definition is invalid.
  • Pin flag option on beam in explicit analysis now works as expected.
  • Programming error no longer occurs with STEADY analysis when the model has DMIG.
  • DOPTPRM,TOPDISC option no longer affects the results of free-size optimization.
  • Error #5127 no longer occurs in Darcy flow model when MAT5.
  • Programming error no longer occurs in a radiation to space heat transfer analysis when the initial condition is used to refer to the temperature in previous subcase.
  • Internally generated grid IDs in the _nl.out file have been removed.
  • MOTNJG no longer uses the position of the previous load case when FIXED is selected even if CNTNLSUB is not defined.
  • A particular mode is now properly post-processed in HyperView with the .h3d file in case there are repeated modes (same frequencies).
  • The results accuracy with PARAM,VMOPT,2 with SPCD loading has been improved.
  • The performance for frequency response analysis with pressure loading has been improved.
  • Error #1898 from optimization with frequency response and random response using Von Mises and principal stresses/strains responses no longer occurs.
  • Composite bond failure is now available in the .h3d file even if the values are all zero.
  • Shear strain calculation is no longer incorrect for PBEAML BAR cross section.
  • TIE contact now works correctly when one side of TIE is very soft.
  • Very large disk space is no longer required for transient subcase if a static subcase with pretension bolt is included.
  • Von Mises stress calculation for BOX/BOX1 section is now correct.
  • MFLUID with PARAM,VMOPT,2 in dynamic reduction (CMSMETH) with ASET has been revised to improve the accuracy.
  • Electrical anisotropic material with cylindrical coordinate system now works correctly.