modal analysis/beam with loads
modal analysis/beam with loads
(OP)
In ANSYS, the only "loads" valid in a modal analysis are displacement constraints. How do you determine the modes of a structure with real loads, such as a beam supporting heavy equipment?
I tried running a static analysis, saved the file, started a new "modal" analysis and requested that Prestress be included, but the results are still for a structure with no loads.
Thanks
I tried running a static analysis, saved the file, started a new "modal" analysis and requested that Prestress be included, but the results are still for a structure with no loads.
Thanks





RE: modal analysis/beam with loads
By carrying out a free vibration eigenvalue analysis (antype,modal) like everyone else. This is a modal analysis of a system FREE of external loads, and thus shows potentially how the structure would respond (mode shapes - eigenvectors - and corresponding eigenvalues) to a dynamic load input. If you want to see how your system responds dynamically, run a transient dynamic analysis with a dynamic load input, not a free vibration.
>I tried running a static analysis, saved the file, started a new "modal" analysis and requested that Prestress be included, but the results are still for a structure with no loads.
You can include pre-stress if you want, but make sure the pstres,on option is switched for BOTH the static and the modal analyses (not just one).
Cheers,
-- drej --
RE: modal analysis/beam with loads
Cheers
Greg Locock
RE: modal analysis/beam with loads
David R. Dearth, P.E.
Applied Analysis & Technology
E-mail "AppliedAT@aol.com"