Altair HyperLife 2020 Release Notes

New Features

Vibration Fatigue
Vibration fatigue analysis can be performed with the following loading options to predict fatigue in the frequency domain:
Random Response Fatigue with PSD Stress Input
PSD stress from a random response analysis is input to perform random response fatigue analysis with stress life (SN) and strain life (EN) approaches. Currently, OptiStruct (H3D) result formats are only supported as an input file.
Random Response Fatigue with PSD Input (mag and phase OR real and imag)

FRF stresses (from FRF analysis), together with PSD as loading, are input to perform random response fatigue analysis with stress life (SN) and strain life (EN) approaches. Currently, OptiStruct (H3D), Nastran (OP2), and Abaqus (ODB) result formats are supported as input files. PSD has to be input in CSV format.

Sine Sweep Fatigue
With the input swept-sine, fatigue analysis can be performed in sine sweep vibration to determine the fatigue life of the specimen with stress life (SN) and strain life (EN) approaches. Currently, OptiStruct (H3D), Nastran (OP2), and Abaqus (ODB) result formats are supported as input files.


Figure 1. HyperLife Vibration Fatigue Process
Modal Superposition
Fatigue analysis can be performed when modal stresses and modal participation factors are available in two different file inputs.

Modal stresses are multiplied by modal participation factors then summed at each point in time. The modal stress file (geometry) is supported for the H3D file format. The supported modal participation factor file formats are PCH and MRF. Currently, only time domain results (from transient analysis) are supported.

Safety Factor Estimation
“Safety Factor” is available as output with SN analysis for constant mean stress and constant stress ratio.
Temperature Influence
Temperature influence is considered based on the FKM guideline by input “Temperature factor” to modify the endurance limit for SN analysis.
Surface Finish
User-defined input value is enabled in the Material tool.
Surface Treatment
User-defined input value is enabled in the Material tool.
Seam Weld Fatigue
Two row fillet welds and overlap welds are supported (only with Time Series loading).

Enhancements

Setup Analysis
Type of Loading
The following fatigue loading options are available to set in the collated stress-life (SN) and strain-life (EN) tools:
  • Time Series
  • Transient Response
  • Modal Superposition
  • Random (PSD Stress)
  • Random (Input PSD with FRF)
  • Sine Sweep

One of the above options is selected based on the available fatigue loading history to be input in the Load Map tool. Time Series is set as default

Damage Models
Damage models are the different probability density functions available for vibration fatigue when the Type of Loading is set to Random.
User Warning for Supported Input File Formats
With file load or file drag-and-drop-drop together with the "Type of Loading", a warning pops up to hint you about the supported file types.
Stress Combination
Default stress combination is set to "Abs max principal".
Layer Selection
For shell models, default layer is set to "Worst".
Material Tool
The following enhancements are available in the Material tool:
  • When FOS is selected as the fatigue analysis type, the Material tool is dynamically updated and streamlined to show input parameters specific to FOS-Dang Van calculations.
  • Temperature factor: An exclusive column is added for "Temperature factor" input (based on the FKM guideline).
  • User defined Values: The UI is updated to accommodate user input values for "Surface treatment" and "Surface finish".
Load Mapping Tool
The following enhancements are available in the Load Map tool:
  • Block Loading Utility: The format has been updated for better simplified viewing when written out.
  • The LDM, Scale and offset input can’t accept zero.
  • The quasi-static load increments are available as loadsteps (under "Subcase") from OptiStruct and Abaqus simulations.

    Only the last step of the increments will be shown in “loadmap”. For result files with load increments greater than 1, they will be listed in both Static and Transient type of loading.

Evaluate
The following enhancements are available in the Evaluate tool:
  • Safety Factor output: Options available to request safety factor output for constant "Mean" or "Stress Ratio".
  • Target Life: When Safety Factor output is requested, Target Life can be input.
Results Context
The following enhancements are available in the results context:
  • The result contour legend is automatically reversed for Life, Safety Factor, and FOS output.
  • Rainflow data can be exported for SN and EN analyses (including Random and Sine Sweep) for the queried element.
  • Right-click options available with legend context menu.

Resolved Issues

The earlier known issue with the following solver result types are resolved with "Time Series" loading:
  • LS-DYNA results (D3PLOT)
  • Radioss results (H3D)
The earlier known issue with the following solver result types are resolved with "Transient response” (transient analysis):
  • LS-DYNA results (D3PLOT)
  • Radioss results (H3D)
  • Abaqus (ODB)
  • ANSYS (RST)

Known Issues

  • When multiple result files are loaded (with the same geometry), the loadcases (loadstep) can’t have identical names. The workaround is to create derived a loadcase with a different name using the Loadcase tool.
  • Derived loadcases are not supported with Random loading.
  • Model Superposition: A known issue exists where parts selected for analysis of large models may take a longer time. This will be addressed in the upcoming release schedules.