Majoj,

Perhaps it will not be possible for COADE to do so as or the higher order acoustic modes, we need to use shell elements . My undertanding is that COADE will stick to beam element based FEA only ( Richard/Dave correct me if I am wrong).

MSM , as pointed out by others, 4Hz has nothing to do with higher acoustic modes which excites the shell modes, frequencies sometimes reach as high as 3000 Hz.


Regards