I am trying to run Modal acoustic analysis for this periodic structure. I keep running into errors. I also tried running normal modal analysis. Both times "unknown error occurred during solution" is brandished.It would be greatly helpful if I could troubleshoot this. I also have the ACT extension,If that makes a difference.
the error is
*** ERROR *** CP = 21.141 TIME= 16:29:23
This model contains the viscous damped materials in a modal analysis
without selecting the damped eigen solver (MODOPT,DAMP). The WB user
must suppress the viscosity assigned to the acoustic region in the WB
Engineering Data, if the viscosity is ignored.
Thank you,in advance.