Mechanical APDL Structural Analysis Guide

6.3.4.8. Specify Analysis Type and Options.

1. Choose menu path Main Menu> Solution> Analysis Type> New Analysis. The New Analysis dialog box
   appears.


2. Click on "Modal" to select it and click on OK.The New Analysis dialog box closes.


3. Choose menu path Main Menu> Solution> Analysis Type> Analysis Options. The Modal Analysis dialog
   box appears.


4. Click on "Block Lanczos" as the mode-extraction method [MODOPT].


5. Enter 3 for the number of modes to extract.


6. Enter 1 for the number of modes to expand [MXPAND].


7. Click on the Calculate elem. results dialog button [MXPAND] to specify YES.


8. Click on OK.The Modal Analysis dialog box closes, and the Block Lanczos Modal Analysis dialog box ap-
   pears. Click OK to accept the default values.

6.3.4.9. Solve the Modal Analysis

1. Choose menu path Main Menu> Solution> Solve> Current LS. The Solve Current Load Step dialog box
   appears, along with a status window.


2. Carefully review the information in the status window, and then click on Close.


3. Click on OK on the Solve Current Load Step dialog box to start the solution.


4. When the solution is finished, a dialog box stating "Solution is done!" appears. Click on Close.

6.3.4.10. Set Up the Spectrum Analysis

1. Choose menu path Main Menu> Solution> Analysis Type> New Analysis. The New Analysis dialog box
   appears, along with a warning message that states: "Changing the analysis type is only valid within the
   first load step. Pressing OK will cause you to exit and reenter SOLUTION. This will reset load step count
   to 1." Click on CLOSE to close the warning message box.


2. Click on "Spectrum" to select it, and click on OK.The New Analysis dialog box closes.


3. Choose menu path Main Menu> Solution> Load Step Opts> Spectrum> Single Point> Settings. The
   Settings for Single-point Response Spectrum dialog box appears.


4. Select "Seismic displac" in the scroll box as the type of response spectrum.


5. Enter 0,1,0 for excitation direction into the excitation direction input windows and click on OK.

6.3.4.11. Define Spectrum Value vs. Frequency Table

1. Choose menu path Main Menu> Solution> Load Step Opts> Spectrum> Single Point> Freq Table.
   The Frequency Table dialog box appears.


2. Enter 0.1 for FREQ1, enter 10 for FREQ2, and click on OK.

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

Spectrum Analysis