Modal Acoustic analysis

  • Last Post 21 August 2019
hhusker posted this 19 August 2019


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.


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HuiLiu posted this 19 August 2019

Hi hhusker,

The default engineering data contains viscosity. You can suppress them from engineering data before you run the model. Otherwise, you'll need to switch to damped solver for your modal analysis, under analysis setting.


hhusker posted this 20 August 2019

I did try damped solver.but then ends up with 9 warnings and the solver still doesn't produce the solution. I got it running if i suppress the acoustic body in modal analysis. Wouldn't that be a problem if I couple for harmonic an use acoustic body?

hhusker posted this 20 August 2019

Should I suppress the material or can we suppress just viscosity?

HuiLiu posted this 20 August 2019

You can just suppress the viscosity.

hhusker posted this 21 August 2019

I did that but the error comes asking to neglect thermal conductivity. Even after that it refuses to run,there are no errors but 9 warnings in the soln information.