Free Modal Anaylsis
I am trying to perform a free modal analysis on a 3U CubeSat. In this model, no fixed supports were introduced. For the attachment of the side panels to the rails (4 long slender components), I used a bonded contact with the formulation MPC as shown in the second screenshot. I used pinball radius at the holes of the side panels. In this first model there is a top plate shown in the 4th screenshot but no bottom plate as shown in the 3rd screenshot. The results I got for the eigenfrequencies make somehow sense as it is expected that the eigenfrequencies for the first 6 modes are 0. BUTTT!!
After introducing a bottom plate, PCB with 2 connectors, connector at side panels in Pic 3, using bonded contact with same formulation as above & point mass, the eigenfrequencies I got are 0 for all 9 modes and this phenomenon starts occurring, the PCB is detached from the connectors which does not make any sense as is it supposed to be intact because of the bonded contacts as shown in the second last picture. Last picture shows properties of point mass defined. The reason for using point mass is because the PCB contains other electrical components in itself.
Could anyone explain why this is happening. Cant seem to figure out. Thank you in advance!