Synthesize FRFs from mode shapes. All modal parameters (modal mass, damping, frequency, and shape) known. Assumes real mode shapes.
fsyn = frfsyn(shp,fproto,ref,res)
FSYN=FRFSYN(SHP,FPROTO,REF,RES) returns an NrefxNres imat_fn with synthesized frequency response functions for the selected reference and response coordinates. SHP should be an imat_shp, REF and RES should be imat_ctrace objects, and FPROTO should be an imat_fn with the desired abscissa, or a list of frequencies.
Hysteretic (structural, eta) damping activated by specifying SHP(1).idline3='hysteretic'. Note that SHP.damping always corresponds to viscous damping (zeta). eta = 2*zeta.
NOTE: This version works for real or complex modes, hysteretic or viscous damping.
>> st=readadf;
>> proto=imat_fn(‘abscissa’,[1:1:1600]);
>> res=alldof(st);ref=res(1:2);
>> fsyn=frfsyn(st,fproto,ref,res)