求斜拉索 激振频率与索振幅值的关系

beyondwqh

/title, cable
/prep7
et,1,link10
r,1,3.14E-6,0.001
mp,ex,1,2e11
mp,dens,1,7850
n,1
n,21,2,1.1547
fill
e,1,2
egen,20,1,1
d,all,all
ddele,2,ux,20
ddele,2,uy,20
finish
/solu
antype,static
pstres,on
outpr,basic,1
solve
finish
/solu
antype,modal
modopt,subsp,4
mxpand,4
pstres,on
solve

代码到这里，得出了前4阶模态、振型。请问如何得出激振频率与索振幅值的关系？谐响应分析可行吗？