General

General

In ANSYS nCode DesignLife is it possible to do a fatigue analysis for a Sine-On-Random vibration loading?

    • FAQFAQ
      Participant

      Yes. To do a sine-on-random vibration fatigue evaluation in DesignLife, you need to convert the sine signal and random vibration spectrum to a combined time-history loading. You then need to run a mode-sup transient analysis using that time history loading (you need to save the modal stresses and the .mcf file). You then need to run a Time Series SN analysis using that time history. The steps are summarized below: 1. Open DesignLife 2. Drag TSGenerator Glyph (from Input Palette) onto Workspace 3. Open Properties for TSGenerator Glyph a. Set Operation to be “SineOnRandom” b. Enter data for PSD spectra and sinusoidal loading (note: this glyph will the convert PSD and sinusoidal input into time history loading) 4. Drag TS_to_FE_Table Glyph (from DL Palette) onto Workspace and connect its input to an output from the TSGenerator 5. Open Properties for TStoFETable and Set Program to “ANSYS” (note: this glyph will convert the time history loading generated by TSGenerator into loading versus time table for use in the FE. It will be stored in xml file that can be imported into ANSYS Mechanical to be used as tabular force input for a mode-supe, time-history analysis) 6. Run DL to create time the Time Series loading (note: XYDisplay and DataValueDisplay glyphs can be connected to TSGenerator to view the created time history loading) 7. Exit DL 8. Open Workbench and set-up mode-supe transient analysis (note: DL needs the modal stresses from the modal analysis and the mode coefficients from the transient analysis) 9. In the modal analysis: save only the stress 10. In the transient analysis a. do not save anything (Mechanical will always store DOF results, but they are not needed b. issue TRNOPT,MSUP,,,,YES from within a Command Object to store mode coefficients in a file.mcf file c. import the time history loading from the XML file previously generated as a table load for the appropriate force 11. Solve Mechanical 12. On WB project schematic, connect SN TimeSeries system to the Solution cell of the modal system and the Engineering Data cell of the transient system 13. Within DL: a. delete the TSInput Glyph b. drag a Modal Coord Input Glyph (from DL palette) onto the workspace c. connect Modal Coord Input Glyph to SNAnalysis Glyph d. From Available Data: i. drag modal stress results file (file.rst) onto FEInput Glyph ii. drag modal coordinates file (file.mcf) onto Modal Coord Input Glyph 14. Run DL analysis and post-process