Modal analysis sample input file?

[Son_new]

Dear All,

Does anybody can give me the example file for the modal analysis of frames or any type of element?

Regards,

[Son_new]

here is my sample input file,

It works to some extent but I'm not sure whether it is composed in correct way or not.
Interestingly it doesn't converges with other commercial packages where it was converge for
the different type of problems. 

Code: [Select]

FEAP * * 3-D Truss Problem
4 3 1 3 6 2

MATErial,1
frame
ELAStic ISOTropic 10.e6, 0.38
mass consistent
CROSs SECTion 0.15, 3.125e-3, 1.125e-3, 0, 2.817e-3
REFErence VECTor or NODE or DIREction
density data 100
body forces 0, 0, -1

COORdinates
1 0 0.0 0.0 0.0
2 0 0.0 0.0 6.0
3 0 6.0 0.0 8.0
4 0 6.0 0.0 0.0

ELEMents
1 0 1 1 2
2 0 1 2 3
3 0 1 3 4

BOUNdary restraints
1 0 1 1 1 1 1 1
4 0 1 1 1 1 1 1

FORCe
3 0 5000 5000 5000 0 0 0
END

BATCh
 TANGent
 FORM
 SOLVe
 DISPlacement ALL
END

STOP

Regards,

[FEAP_Admin]

Attached is an input file showing a basic example of modal integration.
Main steps are: (1) define input and proportional loading, (2) compute eigenvectors/values, (3) loop over time using MODAl to advance the equations using the modal time integrator (which is exact per time-step assuming linear variation in the loads over each time step).  See chapter 14 of the manual.

[Prof. R.L. Taylor]

The manual describes modal analysis (Sec 14.5 in current one).  However, a simple beam vibration problem is attached.

[Prof. R.L. Taylor]

Sorry, file attached here