ABAQUS Analysis User's Manual  

25.2.37 UPSD
User subroutine to define the frequency dependence for random response loading.

Product: ABAQUS/Standard  

References

Overview

User subroutine UPSD:

  • will be called once for each frequency at which calculations will be made during a random response analysis if the frequency function is defined in a user subroutine;

  • is used to define complicated frequency dependencies for the cross-spectral density matrix of the random loading; and

  • ignores any data given for the associated frequency function outside the user subroutine.

User subroutine interface

      SUBROUTINE UPSD(PSD,PSDR,PSDI,FREQ,KSTEP)
C
      INCLUDE 'ABA_PARAM.INC'
C
      CHARACTER*80 PSD

      user coding to define PSDR and PSDI

      RETURN
      END

Variables to be defined

PSDR

Real part of the frequency function at this frequency.

PSDI

Imaginary part of the frequency function at this frequency.

Variables passed in for information

PSD

User-specified name for this frequency function definition, left justified.

FREQ

Frequency, in radians per time.

KSTEP

Step number.

Example