How do you perform a PSD analysis with different excitations?
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In ANSYS Release 10.0, you need to specify each excitation type and direction and issue a PFACT command to calculate the participation factors. After all of the participation factors have been calculated, you issue one solve command (see simple example below). ! Simple 3 Beam Fixed-Fixed Frame ! N2---E2---N3 ! ! ! ! ! ! ! E1 E3 ! ! ! ! ! ! ! N1 N4 nmodes = 5 /prep7 et,1,188 mp,ex,1,10e6 mp,prxy,1,.3 mp,dens,1,1e-3 sectype,1,beam,rect secdata,1,1 n,1 n,2,0,10 n,3,10,10 n,4,10 e,1,2 e,2,3 e,3,4 d,all,uz,0 d,1,all,0 d,4,all,0 ! Do modal analysis and extract min and max frequency /solu antype,modal modopt,lanb,nmodes mxpand,nmodes,,,yes solve *get,min_fr,mode,1,freq *get,max_fr,mode,nmodes,freq /post1 set,list ! Do PSD ! Excite N1 in the X direction and N4 in the Y direction /solu antype,spectrum spopt,psd,nmodes,yes ! X direction excitation of N1 psdunit,1,disp ! type response spectrum d,1,ux,1 ! location and direction of excitation psdfrq,1,1,min_fr*1/2,max_fr*2 ! frequency points for spectrum curve psdval,1,.01,.01! spectrum values (constant) pfact,1,base ! performs linear static analysis to ! calculate participation factors ! Y direction excitation of N4 psdunit,2,disp d,4,uy,1 psdfrq,2,2,min_fr*1/2,max_fr*2 psdval,2,.01,.01 pfact,2,base dmprat,.01 ! 1% damping psdcom ! power spectral density mode combination method solve /post1 set,3,1 ! 1 sigma displacement values prnsol,dof |
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