A modal analysis was performed on a 100x100x2mm steel plate using Nastran SOL 103. The first 4 mode shapes and their associated frequencies were extracted. The model had over 100 elements and the material properties and boundary conditions were defined. The mode shapes were plotted to visualize the vibration patterns at different frequencies.

1. Modal Analysis Of Plate
(Nastran SOL 103)
FE Model of Plate 100x100x2mm thick
Material Steel:- E- 2.0E5
N/mm2
,
Density = 7.8E-9
tonnes/mm3
, mu=0.3

2. Create load collector
The created loadcol is set as current loadcollectorCard image = EIGRL

3. Enter no. of modes to extract
EIGRL Card Image

4. EIGRL Real Eigenvalue Extraction Data, Lanczos Method

5. EIGRL Real Eigenvalue Extraction Data, Lanczos Method

6. Create Loadstep from Analysis Page Menu
Click create then edit for output requests

7. Select the output requests

8. Select the output requests
ESE – Element Strain Energy

9. On Analysis Page menu select control cards

11. Scroll to select
the parameters
Select Parameters as shown below

12. Type ECHO=NONE for CASE_UNSUPPORTED _CARDS

13. Export the file into specified directoryFile export

14. plate_modal.dat
Open the exported file

15. Plate Modal Analysis Deck file , plate_modal.dat

16. Plate Modal Analysis Deck file , plate_modal.dat

17. Submit Nastran Run
Click On the Shortcut to open the
file. Select the file
In command Info window
Type
SCR=YES OLD=NO

18. Check .f06 file for warnings, errors, frequencies
Freq. in
Cycles
Freq. in
rad/sec
Square of
(Freq. in
rad/sec)

19. Plot Various Mode Shapes
1st
Frequency – 168.5 Hz 2nd
Frequency – 407 Hz
3rd
Frequency – 1017 Hz 4th
Frequency – 1279 Hz