Nastran Modal Transient & Response Spectrum Analysis for Base Excitation

• Shock and vibration analysis can be performed either in the frequency or time domain
• The time domain method requires more computation time but is much better suited for transient and nonstationary excitation
• Time domain methods are also better for rainflow fatigue cycle counting
• Students should already have some familiarity with Femap & Nastran
• They should also be able to perform SRS time history synthesis as shown in previous Vibrationdata units
• NX Nastran is used as the solver, but the methods should work with other versions
• Two units for direct shock response spectrum analysis is also included

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Prerequisite Materials

Webinar Index

Structural Dynamics Webinars

Matlab Vibrationdata GUI

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Main Presentations:

Nastran Modal Transient Slides:  200_FEA_modal_transient_revJ.pptx  & Alternate Link

Nastran FEA Base Excitation via Response Spectrum:  201_FEA_response_spectrum_revE.pptx & Alternate Link

Nastran FEA Base Excitation with Multiple Response Spectrum Inputs:  202_FEA_response_spectrum_multiple_revA.pptx & Alternate Link

Nastran FEA Frequency Response Function for Base Input:
203_FEA_frf_revB.pptx & Alternate Link

FEA PSD Response for Base Excitation using Femap, Nastran & Matlab:  204_FEA_psd.pptx & Alternate Link

Avionics Component Shock Sensitivity & FEA Shock Analysis:  avionics_box_fea_shock.pptx & Alternate Link

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Nastran Files

Students should generate their own files, but here are several for reference:

square_plate_normal_modes.bdf

square_plate_modal_transient_seismic_mass.bdf

square_plate_response_spectrum.bdf

square_plate_response_spectrum_multiple.bdf

square_plate_response_frf.bdf

square_plate_psd.bdf

Nastran Acceleration Time History:  srs2000G_accel.nas

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See also:    Vibrationdata Nastran

– Tom Irvine