Mechanical APDL Structural Analysis Guide

6. Repeat steps 4 and 5 for additional response spectra, if any. Note that solutions are not written to the
   Jobname.rst at this time.

The mode combination phase writes a file of POST1 commands (Jobname.MCOM). Read in this file

in POST1 to do the mode combinations, using the results file (Jobname.RST) from the modal ex-

pansion pass.

The file Jobname.MCOM contains POST1 commands that combine the maximum modal responses

by using the specified mode combination method to calculate the overall response of the structure.

The mode combination method determines how the structure's modal responses are to be combined:

• If you selected displacement as the response type (label = DISP), displacements and stresses are
  combined for each mode on the mode combination command.


• If you selected velocity as the response type (label = VELO), velocities and stress velocities are
  combined for each mode on the mode combination command.


• If you selected acceleration as the response type (label = ACEL), accelerations and stress acceler-
  ations are combined for each mode on the mode combination command.

7. Leave the SOLUTION processor.
   Command(s):FINISH
   GUI:Close the Solution menu.

If needed, you can retrieve the frequencies, participation factors, mode coefficients and effective

damping ratios with the *GET command (Entity = MODE).

6.2.4. Step 4: Review the Results

Results from a single-point response spectrum analysis are written to the mode combination file,Job-
name.MCOM, in the form of POST1 commands. These commands calculate the overall response of the
structure by combining the maximum modal responses in some fashion (specified by one of the mode
combination methods). The overall response consists of the overall displacements (or velocities or ac-
celerations) and, if placed on the results file during the expansion pass, the overall stresses (or stress
velocities or stress accelerations), strains (or strain velocities or strain accelerations), and reaction forces
(or reaction force velocities or reaction force accelerations).

You can use POST1, the general postprocessor, to review the results.

Note

If you want a direct combination of the derived stresses (S1, S2, S3, SEQV, SI) from the results

file, issue the SUMTYPE,PRIN command before reading in the Jobname.MCOM file. With the

PRIN option, component stresses are not available.

The command default (SUMTYPE,COMP) is used to directly operate only on the unaveraged element
component stresses and compute the derived quantities from these. Refer to Creating and Combining
Load Cases in the Basic Analysis Guide. Also, see the Command Reference for a description of the SUMTYPE
command.

1. Read the commands on Jobname.MCOM:
   Command(s):/INPUT

Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information

Single-Point Response Spectrum (SPRS) Analysis Process