What's New
View new features for OptiStruct 2020.1.
Altair OptiStruct 2020.1 Release Notes
Highlights
- Energy output for Nonlinear Static Analysis
- Explicit Dynamic Analysis - Additional Elements supported
- Aeroelasticity – Static Trim solution
- User subroutine for Heat Transfer Analysis
- Thickness mapping from Forming simulation
- Material and property Encryption
New Features
- Energy output for Nonlinear Static and Nonlinear Transient Analysis
- Various energy output is available for the entire model and/or the
SET of elements or Contact.
- Plastic Energy dissipation -> Entire model and/or SET of elements
- Static Stabilization energy -> Entire model and/or SET of elements
- Contact Stabilization energy -> Entire model and/or each CONTACT
- Damping option for JOINTG
- "DAMP" has been added as new property type in PJOINTG Bulk Data to specify damping for JOINTG. Currently, hinge, axial, and cylindrical joints are supported for damping input.
- ADJUST option on CONTACT now considers the shells thickness in searching zone
- Prior to v2020.1, ADJUST did not consider the thickness of shells in search zone but the shell thickness is now considered for ADJUST. For example, the penetration could be considered by considering the thickness of shells so that ADJUST in v2020.1 will properly defect the penetration and adjust the grids.
- Baseline correction
- Some errors in measured acceleration input causes the divergence of transient analysis for results such as displacement even at the end of simulation. Baseline correction helps correct the acceleration input to avoid such phenomena. Baseline correction is supported for Nonlinear Transient Analysis and activated by the BASELIN Bulk Data Entry and Subcase Entry. Baseline correction is only applicable when the acceleration input is through SPCD with TLOAD# data.
- CONROD element support in Large Displacement Nonlinear Analysis
- CONROD elements are now available in Large Displacement Nonlinear Analysis.
- Enhanced NLMON Bulk Data
- Monitoring of displacement for user-specified grid and component is now available through the NLMON Bulk and Subcase Data Entries.
- HyperBolic Sine Creep law
- HyperBolic Sine Creep law is now available. For this material law, temperature is directly included in the formulation. CTYPE=HYPERB is available on the MATVP Bulk Data Entry.
- New combination joints via JOINTG (Cartesian + Orientation)
- CARTORIE JOINTG type is now available as a combination of Cartesian and Orientation joints.
- Temperature loading support for Nonlinear Transient and Static Analysis
- TEMP(D) Bulk Entry can now be referenced by TLOAD1/2 to specify temperature loading. Temperature-dependent material is also supported under this loading.
- Centrifugal Softening for preloaded Normal mode analysis with Large Displacement Nonlinear Analysis
- Centrifugal Softening for preloaded Normal Mode Analysis with Large Displacement Nonlinear Analysis has been considered by default.
- Additional diagnostic data in _nl.out and _nl.h3d files
- Grid IDs with Contact Status Change and distorted element IDs are available in _nl.out ASCII file, as well as the _nl.h3d file. NLPRINT Bulk/Subcase Entry should be used to request the grid IDs with contact status change output in _nl.out file. In _nl.h3d file, grid IDs with contact status change and the distorted element IDs are always output by default.
- Model Change (MODCHG) support for RBE2/RBE3
- Subcase-dependent model change for RBE2/RBE3 is now supported. The set of rigids should be defined through a SET of TYPE=RIGID. Both with-strain and without-strain activation option is supported.
- Alternate shell formulation for 1st order shells for Large Displacement Analysis
- PARAM,SHELLLG,YES activates an alternate 1st-order LGDISP shell element (CQUAD4 and CTRIA3). PARAM,SHELLLG,YES introduces numerous departures from the original element design (Total Lagrangian formulation, element interpolation spaces, drill DOFs treatment, and quadratures). It is recommended for sensitive models.
- BEAM/BAR
- Beam/Bar element through CBEAM/CBAR has been added for Explicit Dynamic Analysis. The formulation is based on Belytschko-Schwer Beam theory. This formulation considers transverse shear deformation as in Timoshenko beam theory. PBEAM, PBAR, PBEAML, and PBARL properties are supported.
- CBUSH with linear and nonlinear stiffness
- CBUSH Bulk Entry has been added to represent the bushing modeling capabilities in explicit dynamic analysis. The stiffness can be linear (PBUSH) or nonlinear (PBUSHT) based on the properties chosen. Mass is required for CBUSH through “M” continuation line on PBUSH.
- First Order Tetra with Nodal pressure average
- First order tetra elements with nodal pressure average can alleviate volumetric locking and is the default for first order tetra elements. Regular first order tetra element can be activated thru ISOPE field on PSOLID continuation line.
- RBE3
- RBE3 is now supported for Explicit Dynamic Analysis.
- Max time step limit on TSTEPE
- DTMAX (Maximum allowed time increment) has been added in the TSTEPE Bulk Entry.
- Bergstrom-Boyce Material Model
- This material law represents the nonlinear viscoelastic characteristics of material and can be combined with any Hyperelastic materials that are supported. Currently, only solid elements are supported. MATVE Bulk Entry is used to define this type of material.
- Frequency control for plotting of energy results
- FREQ option on NLENRG Bulk Entry can be used to control the frequency of output for energy in _expl.mvw file.
- External work as energy output
- External work is now available as one of the energy outputs for plotting.
OptiStruct version 2020.1 supports Static Aeroelasticity capability for subsonic regime. Other aeroelasticity solution types, such as flutter, will be supported in the future release.
The Vortex Lattice Method (VLM) solves the aerodynamic equations for low-speed-linear potential flows by distributing elementary solutions of Laplace’s equation over the boundary surface.
Static aeroelasticity is the study of the deflection of flexible aircraft structures under aerodynamic loads, where the forces and acceleration are assumed to be independent of time. Stability and control derivatives are available for each unique flight condition (Mach number and dynamic pressure). Derivatives are printed for the rigid vehicle and for the restrained and unrestrained elastic vehicles.
A trim analysis is performed that determines unknown trim values. Aerodynamic forces and pressures on the aerodynamic elements may be obtained via the AEROF and APRES Case Control commands, respectively.
The results from TRIM analysis such as stability, control derivatives, the aerodynamic forces and pressures are available in the ASCII ouput file (.trim file).
Monitor points (MONPNT1, MONPN3 Bulk Entry) are available to understand the integrated loading or the force going thru the section of the models. The results of Monitor points are available in the .monpnt file.
Aeroelastic Trim Analysis | Bulk Data | Case Control |
---|---|---|
Structural Model | GRID, Finite Elements, Properties, and so on | |
Aerodynamic Model | CAERO1, PAERO1, AERO, AEROS, AEFACT | AESYMXZ, AESYMXY |
Splines (interpolation) | SPLINE1, SPLINE2, SPLINE4 | |
Boundary Conditions | SUPORT, SPC, SPC1 | SPC |
Aerostatic Trim Analysis | TRIM, AELIST, AELINK, AESTAT, AESURF | |
MONITOR points | MONPNT1, MONPNT3 | |
Structural Output | DISP, STRESS, STRAIN, and so on. | |
Aerodynamic Output | AEROF, AEPRESSURE, TRIMF | |
Aeroelastic Parameters | PARAM,AUNITS |
- MUMPS Solver for Nonlinear Steady-State and Transient Heat Transfer Analysis
- MUMPS Solver for Nonlinear Steady-State and Transient Heat Transfer Analysis is now available and can be activated through the SOLVTYP Bulk/Subcase Entries (the default solver is BCS). Some test results have shown that MUMPS solver provided a better scalability with multiple processors (SMP) than BCS solver.
- Radiation to Space in Transient Analysis
- Radiation to Space for Transient Heat Transfer Analysis is supported.
Radiation boundary conditions can be specified with the RADBC Bulk Data where the radiation view factor is defined and the RADBC entry should be referenced by a CHBDYE entry. In addition, the RADBC entry points to a grid for ambient temperature definition and the ambient temperature can be specified with SPC.
The emissivity and absorptivity material surface properties are specified on the RADM Bulk Data Entry. The RADM entry is directly referenced by a surface element entry (CHBDYE).
PARAM,TABS defines the absolute temperature scale and PARAM,SIGMA defines Stefan-Boltzman constant.
- User subroutine for Thermal Analysis
- User subroutines can be programmed using Fortran or C/C++. A dynamic library built with user subroutine can be loaded with the LOADLIB entry.
- Modal participation output for Equivalent Radiated Power (ERP)
- Modal participation for Equivalent Radiated Power (ERP) is available and can be requested with “MPF” option in ERP output request. The participation results are available in punch and H3D file.
- Mechanical and Thermal Strain output for continuum shells with PCOMPLS
- In addition to the total strain output, mechanical and thermal strains are available with MECH and THRM options on the CSTRAIN output request for continuum shells.
- Failure Criteria Enhancement for PCOMPLS
- Prior to v2020.1, the failure criteria for PCOMPLS assumes the strength limit for thickness direction (local Z) is the same as the strength limit on local y direction thus V5 and V6 on MATF were ignored. The failure criteria has been enhanced such that the strength limit for thickness direction is correctly taken into account.
- Corner option support for CSTRAIN and CFAILURE
- Corner option support for CSTRAIN and CFAILURE is available in H3D file for linear and nonlinear static analysis.
- Max Stress failure Criteria added to MATF
- Max Stress failure Criteria “STRS3D” is now supported on the MATF Bulk Data Entry.
- NDIV support for CSTRESS/CTRAIN in Transient and Frequency Response
- NDIV is now supported for CSTRESS/CTRAIN output in Transient and Frequency Response.
- Support of NU13 input, instead of NU31 for MAT9OR
- SYSSETTING(MAT9ORT=NU31/NU13) has been added to select either NU31 or NU13 for the 8th field on MAT9ORT for Poisson’s ratio for uniaxial 3–direction.
- Multiple Failure Criteria support on MATF
- Multiple Failure Criteria are supported on the MATF Bulk Data by allowing multiple “CRI” lines with different failure criteria. Solid (PSOLID, PCOMPLS) and shells (PCOMP(G), PCOMPP) are supported.
- MMA Optimizer
- MMA optimizer has been added as an additional optimization algorithm to choose from by using DOPTPRM,OPTMETH. MMA can be tried in case the default optimizer, DUAL2, does not provide satisfactory results for topology or topography design variables.
- Improved sensitivity for Contact pressure/force response with Shape design variables
- Accuracy of sensitivity has been improved for contact pressure/force responses with shape design variables. This is the case even when the shape design variables are defined in contact surface domain.
- Flexible Initial thickness for free-size optimization
- Flexible initial thickness can be defined for free-size optimization, based on nodal average thickness or property thickness. If nodal thickness on the element is available, the initial thickness of each element is based on the average nodal thickness for the given elements.
- Material and property Encryption
- Encryption is now available for material and property data, as well as some table data that are referenced by material data.
- Enhanced EIGVSAVE and EIGVRETRIEVE for Modal Transient Analysis
- Partial degrees of freedom are now allowed for EIGVSAVE run if the corresponding retrieve run is Modal Transient analysis. Solver should be AMSES or AMLS in this case.
- Mass and Damping for GENEL
- Prior to 2020.1, only stiffness matrix input has been available on the GENEL Bulk Data. Now mass and damping are also available for matrix input on the GENEL entry.
- Thickness mapping from Forming Solvers
- Thickness results from the forming solvers available in Nastran (.nas) or LS-DYNA (.k) file can be directly mapped to the OptiStruct model without using any pre-processor. Such mapping capability is available even if the mesh between the forming and OptiStruct model is different. Newly introduced MAP Bulk Entry is used to select several options.
- Additional Statistics Results for Transient Analysis
- Mean, RMS, Variance, Standard Deviation are added for statistics output from Transient analysis with STATIS or OSTATIS option on respective output requests. Displacement, Velocity, Acceleration, SPCF and ELFORCE support these additional statistics output.
- Enhanced Stress results calculation for 2nd order shells
- PARAM,CURVSHL2,THICK activates an alternative stress recovery calculation in curved, 2nd-order shell elements (CQUAD8 and CTRIA6). It is recommended for very thick shells.
- HDF5 Enhancements
- The output file format for Hierarchical Data Format, version 5, has been
switched from .hdf5 to .h5.
The new .h5 file replaces the old
.hdf5 file. The .h5 file
is now output whenever HDF5 output is requested.
- This format contains both model and result information and hence can be used for post-processing directly.
- The old format (.hdf5) does not contain finite element model information and hence requires importing the model file in addition to importing the result file in a post-processor.
- PARAM,HDF5 can be used to switch between the
old and new formats or output both formats. The options for this
parameter are:
- FORM1: Switches to old format (.hdf5)
- FORM2: Switches to new format (.h5). This is the default option.
- BOTH: Both old and new formats are output
- Adaptive time step for Linear Transient
- Adaptive time step schema has been added for Linear Direct Transient Analysis with the Newmark beta time integration method. MREF continuation option on TSTEP controls adaptive time stepping (default is ON), similar to Nonlinear Transient analysis. TMTD continuation option on TSTEP Bulk should be used in case Newmark Beta time integration method is to be used for Linear Direct Transient analysis.
- Remote Job submission using the Solver Run manager
- Remote Job submission is now available using the HWSolver Run Manager.
This allows you to submit a job to a remote machine. The actual run will
be performed on the remote machine and the results are copied back to
the client machine (where the job was initiated using the Run Manager).
The remote machine may be a single host or a cluster. The client machine
can be Linux or Windows; however, the remote machine should be Linux.
Client machines using Windows are currently not supported.
Client Machine Remote Machine Support Linux/Windows Linux Supported Linux/Windows Windows Not Supported Linux/Windows PBS (Linux) Supported Linux/Windows PBS (Windows) Not Supported
- Multi-Level DDM support for Nonlinear Static Analysis
- DDM is now supported for the case where there is a main Pretension bolt subcase then the rest of the subcases are all independent but each of those subcases are continued from the main pretension bolt subcase.
- AVX2 compiler option enabled
- Advanced Vector Extensions 2 (AVX2) instruction set is suitable for floating point-intensive calculation and would help improve the robustness of such calculations. Due to this change, there could be some difference in the results if the model setup is not robust. If the model is setup properly, there should not be noticeable difference in results.
Known Issues
- MPI multi-node cluster runs on Linux may error out due to an SSH error
- For example, the following error may
occur:
Error :/bin/ssh: $ALTAIR_HOME/altair/hwsolvers/common/python/python3.5/linux64/lib/libcrypto.so.10: version OPENSSL_1.0.2 not found (required by /bin/ssh).
Resolved Issues
- No separation was not respected for CONSLI type of contact and this has now been fixed.
- Body force such as gravity for Explicit Dynamic Analysis is now handled properly.
- GPFORCE is correct for Nonlinear Analysis with temperature loading.
- FLAT table option for plasticity is now properly implemented.
- Stress combination “Signed Max Shear” results for Fatigue is corrected for shells.
- ASSIGN entry used for MMO runs now supports up to 600-character length.
- DRESP3 with COMPOSE jobs no longer show some issues with older versions.
- Complex DMIG input no longer causes some issues when the imaginary part is zero.
- MFLUID is now properly supported even for optimization runs.
- OptiStruct runs finish properly when OUTPUT,FSTOSZ is defined and the design space includes STACK and PSHELLs.
- Preloading analysis with centrifugal force applied in static analysis produces results when the centrifugal force is applied on element SET.
- GPKE results no longer are incorrect if the job runs with DDM mode.
- Design Sensitivity Analysis (DSA) no longer ends with programing error when the model has material sizing design variables.
- PFMODE results are available when DSA was performed at the same time.
- Initial velocity is interpreted properly in Explicit Dynamic Analysis when applied on the same DOFs as enforced acceleration.
- When a single SN curve is defined with (SNCM flag on MATFAT card) TABLEXN, the fatigue damage results are now correct.
- Shell thickness is considered properly for ADJUST with CONSLI.
- Stress responses in topology/free-size design space are printed in the main .out file in Multiple Model Optimization (MMO).
- The input file generated with OUTPUT,FSTOSZ is formatted properly, if the free-size model is in long format.
- NSM with error 2359 (NSM=n control cards allowed only in static subcases) occurred even if there was only a single subcase in the model and this is now fixed. With single subcase in the model, the error 2359 will not occur regardless of where NSM entry is defined (subcase level or global level).
- Thickness output from large displacement nonlinear analysis is accurate with DDM mode.
Altair OptiStruct 2020 Release Notes
Highlights
- Plane strain element for Nonlinear Analysis
- Cohesive Zone Modeling with contact
- Contact for axisymmetric elements with continuous large sliding
- Temperature-dependent convection coefficient
- Radiation to space
- String (label)-based input file definition – Beta Feature
New Features
- Plane strains
- Plane Strain elements are now available for Linear/Nonlinear Static (both SMDISP and LGDISP), Dynamic Analysis (Normal modes, Transient, and Frequency Response). For nonlinear analysis, contact is also supported (node-to-surface only is supported. Both small sliding and large sliding with continuous sliding (CONSLI) are supported).
- Large Displacement Analysis support for Viscoelasticity (MATVE) and Creep (MATVP)
- Is now available. Note: Viscoelasticity and creep are currently only supported for solid elements.
- Support for Hyperelastic Material (MATHE) along with Viscoelasticity (MATVE)
- The Hyperelastic material (MATHE) provides the instantaneous response, while the Viscoelastic material (MATVE) defines the relaxation.
- Extended Beam pin flag support for Large Displacement nonlinear Analysis
- Any combination of Pin Flag options on CBAR/CBEAM elements is supported for large displacement nonlinear analysis.
- Axisymmetry with large sliding
- Large Sliding contact for axisymmetry nonlinear analysis is supported. The supported large sliding contact type is continuous sliding (CONSLI). This is supported for node-to-surface contact (N2S).
- Elasto-Plastic material for 1D (beam, bar and rod)
- Elasto-plastic material (MATS1) is supported for 1D elements. Currently, the yield stress only considers axial stress of 1D elements.
- Cohesive Zone modeling with Contact
- Cohesive Zone modeling can now also be accomplished using Contact instead of cohesive elements. The COHE continuation line is now available on the CONTACT Bulk Data Entry and the corresponding MCOHEDID field can reference the MCOHED Bulk Data Entry.
- Temperature loading output
- Temperature loading such as TEMP(D) can be output with OLOAD output request.
- Enhanced Thermal Strain calculation
- New thermal strain calculation is introduced with PARAM,THMLSTN,1. This PARAM is only available for nonlinear static analysis.
- Temperature loading as external file
- Temperature results from an external source in punch file (transient) format can be used as the loading for nonlinear static and transient analysis. Temperature in punch format can be read thru ASSIGN,HFILE. New Bulk Data TEMPT is introduced which references the ID of ASSIGN,HFILE. TEMPT also allows the mapping of temperature results in certain time frame to a specific time frame in structural analysis subcase.
- Enhanced One Step Thermal Transient and Structural Analysis (OSTTS)
- Time-dependent loading with TLOADi/DLOAD for Nonlinear Structural static subcase in OSTTS is supported.
- No Search Distance required when CLEARANCE is defined
- Search Distance for contact is not required if SYSETTING, SRCHDCLR is set to YES and CLEARANCE is defined. In this case, all contact elements within a CONTACT interface (where CLEARANCE is defined) will be generated as if the search distance is set to an infinitely large value. SRCHDCLR can also be set in .cfg file so you can avoid specifying this SYSSETTING in each input file.
- Adaptive Time Step support for Small Displacement Nonlinear Transient
- Adaptive time step is supported for Small Displacement Nonlinear Transient analysis. Default is on and MREF on TSTEP Bulk Data is effective for small displacement nonlinear transient analysis too.
- Summary printing for follower loading
- Summary of follower loading for large displacement nonlinear analysis is printed in the .out file.
Enhancements
- First Order Tetra (TET4) element support
- Supported for Explicit Dynamic Analysis.
- Single Precision executable support
- Is now supported. Executable will have “_sp” in its
name. “
-sp
” solver script option can be specified to use single precision executables. - Penalty-based TIE Contact
- Available for Explicit Analysis and is used automatically when there is over-constraint in the model. Default TIE is still kinematic-based.
- Critical Time Step output
- Critical time step (nodal or elemental) for explicit analysis will be
output in the .out file. This output is also
available after a check run (
-check
script run option). - Edge to Edge Contact for Solids
- The PSURF continuation line is available on the CONTACT Bulk Data. PSIDi entries can reference PSURF Bulk Data IDs.
- Thermal Contact support for Linear/Nonlinear Transient Heat Transfer Analysis
- Is supported.
- Temperature-dependent Convection Coefficient for Steady-State and Transient Heat Transfer Analysis
- Convection coefficient on MAT4 can be temperature-dependent for Steady-State and Transient Heat Transfer analysis. Table input is required and referenced by the corresponding MATT4.
- Temperature-dependent Specific Heat
- Specific heat on MAT4 can be temperature-dependent. Table input is required and referenced by the corresponding MATT4.
- Radiation to Space
- Radiation to Space for Steady-State Heat Transfer Analysis is supported.
- Enforced motion (SPCD) for Modal Frequency Response
- SPCD is supported for Rotor Dynamics with Modal Frequency Response.
- Rotor Energy
- Rotor Energy with RENERGY output request is supported for a model with DMIG or GENEL.
- CGAP Axial U response
- Axial U (displacement) response is supported for CGAP(G). RTYPE in DRESP1 is FORCE and ATTA is UAX.
- Large Shape Change for Frequency Response Optimization
- Some special sensitivity analysis is required for shape optimization that involves CGAP(G), CWELD, CFAST or Node-to-Surface CONTACT in order to allow very large shape changes. This special shape sensitivity is now available for optimization with frequency response analysis.
- Large Shape Change for Heat Transfer Optimization
- Some special sensitivity analysis is required for shape optimization that involves CGAP(G), CWELD, CFAST or Node-to-Surface CONTACT in order to allow very large shape changes. This special shape sensitivity is now available for optimization with Heat Transfer analysis.
- Parallel Computation for MFD, SQP Optimizers
- Is supported with DOPTPRM,OPTIMOMP,YES. The number of
cores for parallel computation is specified with
-nt
script option.
- Integration with VABS
- OptiStruct and VABS are integrated to analyze slender structures via the latter’s ability to compute the complete set of beam section properties for an arbitrary cross-sectional shape and material without any ad hoc kinematic assumptions.
- String (Label)-based Input file definition
- Entities can now be referenced by string labels in the ID field, in
addition to existing integer .Currently, support is available for:
- Category
- Entity
- Materials
- MAT1, MATS1, MAT2, MAT3, MAT4, MAT5, MAT8, MAT9, MAT10
- Properties
- PSHELL, PSOLID, PBEAM, PBAR, PBEAML, PBARL, PBUSH, PCOMP, PCOMPG, PROD, PELAS, PDAMP, PMASS, PGAP
- Sets
- GRID, ELEMENT
- Coordinate system
- All coordinate systems
- Others
- PLY
- References
- Materials
- String labels in the material ID field of corresponding properties are supported.
- Properties
- String labels in the property ID field of corresponding elements are supported.
- Sets
-
- String labels in the set ID field of the following bulk entries are supported: SPC, SPCD, FORCE, MOMENT, PLOAD1, PLOAD2, ACCEL2.
- String labels in the set ID field of output requests are supported.
- Coordinate system
- String labels in the coordinate system ID field of JOINTG entry is supported.
- PLY
- String labels in the PLY ID field of STACK entries are supported.
- String labels characteristics
-
- They are case insensitive.
- String labels are supported in all the Bulk Data formats namely, fixed, large fixed (long) and free formats.
- For string labels longer than 8 characters, it is recommended to use the free format. While strings of any length are allowed in the free format, they will be truncated after 16 characters when processed within OptiStruct.
- They follow the same guidelines as variable names in the existing symbolic substitution feature.
- HyperMesh support for string labels will be available in a future release.
- Subcase-dependent Non-Structural Mass (NSM)
- Is supported for Linear/Nonlinear Static Analysis. The model will error out, if NSM is defined inside any subcase other than Linear/Nonlinear Static subcase.
- AUTOMSET
- Now supported for models with JOINTG.
- PSD/RMS SPCF output
- For Random Response Analysis is now supported.
- Total Memory Requirement output per node for DDM run
- Total memory required for DDM jobs per node is available and printed in the .out file.
- Failure Mode output for HASHIN
- Output for each mode of failure (Fiber tension/compression and matrix tension/compression) is available in the .h3d file for post-processing.
- 1D von Mises stress output for Response Spectrum
- von Mises stress for CBAR/CBEAM with PBARL/PBEAML is available for Response Spectrum Analysis.
- Transient Statistics output
- Support for statistical output request is available in case of Direct
and Modal Transient Analyses in the .h3d file
format.
Output Request Result Type Statistical Results Available CSTRESS - von Mises Stress (available in the individual plies)
- Principal Stress
- Normal stresses (Composite Stresses) in material/ply coordinate system
- Maximum, Time of Maximum
- Maximum/Minimum/Absolute Maximum, Time of Maximum/Minimum/Absolute Maximum
- Maximum/Minimum/Absolute Maximum, Time of Maximum/Minimum/Absolute Maximum, Mean, RMS, Variance, Standard Deviation
SPCF - Magnitude
- For X, Y and Z components
- Maximum, Time of Maximum
- Maximum/Minimum/Absolute Maximum, Time of Maximum/Minimum/Absolute Maximum
ACCELERATION - Magnitude
- For X, Y and Z components
- Maximum, Time of Maximum
- Maximum/Minimum/Absolute Maximum, Time of Maximum/Minimum/Absolute Maximum
ELFORCE - Magnitude
- For X, Y and Z components
- Maximum, Time of Maximum
- Maximum/Minimum/Absolute Maximum, Time of Maximum/Minimum/Absolute Maximum
DISPLACEMENT - Magnitude
- For X, Y and Z components
- Maximum, Time of Maximum
- Maximum/Minimum/Absolute Maximum, Time of Maximum/Minimum/Absolute Maximum
- Element Force/Stress Calculation considering Damping contribution
-
- PARAM,GE4TRSTF for Transient Analysis and PARAM,GE4FRSTF for Frequency Response Analysis. The default value for these parameters is 0.
- If the value is set to 1, then the GE coefficient is taken into account while computing stresses and element forces (can be material/property/NSGE and so on).
- The element forces for CDAMP1, CDAMP2, CVISC and viscous contribution to CBUSH are calculated and output for linear transient analysis.
- Enhanced Mid-edge nodes GPSTRESS output for 2nd order solids
-
- PARAM,EDGESTR,ELEM/NODE is added as the switch for grid point stress calculation for mid-edge nodes.
- EDGESTR=ELEM is the improved method and set as default. The stress at edge is calculated from elemental corner stress first, then averaged between connected elements. The grid point stress at edge might be greater than the stresses at the corners.
- EDGESTR=NODE is the original method. The grid point stress at edge is calculated directly by averaging the grid point stresses at corners
- Enhanced Interface with Multiscale Designer (MDS)
-
- The interface has been enhanced and simplified by now using MATMDS Bulk Data Entry, instead of the old method where MATUSR was used.
- Material data from MDS can be saved in any location on your machine and selected with ASSIGN,MATMDS.
- The LOADLIB entry is not required anymore.
OptiStruct searches for the required library in the same
HWSolvers installation. The MDSDIR I/O Entry
can be used to identify the MDS installation, if OptiStruct and
MDS are in different installation locations
Example:
ASSIGN,MATMDS,Name of Material, MDS material data
MDSDIR = C:\Program Files\Altair\2019\hwsolvers\MultiscaleDesigner
- OLOAD can retain the force applied on single point constraints (SPC)
-
- New options have been added to the OLOAD
entry.
- NOSPC (default)
- Force applied on SPC will be zero.
- SPC
- Force applied on SPC will be retained.
- New options have been added to the OLOAD
entry.
- Random Response Fatigue without rerunning Frequency Response Analysis
- Existing functionality of H3DRES and IMPORT to skip the Frequency Response Analysis is now supported for Random Response-based Fatigue Analysis. With this feature, Frequency Response Analysis does not have to be repeated, if the changes in the model only affect random response or fatigue.
- CPYRAM pyramid element
- CPYRAM pyramid element type in other software will be read the same as CPYRA.
Resolved Issues
- CWELD for Large Displacement Nonlinear Analysis had an issue previously that resulted in non-convergence.
- Test data input for reduced polynominal with Hyperelastic material had an issue, if the order of polynomial is less than or equal to 4.
- Strain output for CBUSH is corrected for Frequency Response Analysis.
- A programming error occured if the model was MPC-based TIE and 2nd order elements.
- Offset (ZOFFS in elements or Z0 in composite property) had an issue.
- Initial Velocity with TICA for Nonlinear Transient had an issue.
- PCOMP(G) for PFBODY was not properly supported.
- Wrong Grid point force which is attached to RBE3 in Large Displacement Nonlinear Analysis is now fixed.
- Radial Draw direction constraints for topology optimization satisfies manufacturing constraints.
- Nonlinear restart run would fail, if the file size went beyond a certain limit.
- CFAST with CID=-1 and MFLAG=1 provides results.
- The stability and results accuracy of continuum shell (PCOMPLS) improved. In prior versions of OptiStruct, an error message could occur, if the dimension of the model was very small.