modelling a 3D composite tube

Hi guys,

I deal with modal analysis of  3D 'both clmaped' composite tube in ANSYS. I use solid elements and orthotropic model of material. Constants of this material are homogenized values of composite tube. So I meshed the tube and set the element coord system ESYS as cylindrical. The problem is with results, becasue after solving I get very low eigenfrequncies, i.e. first 100 eigenfrequencies are from 0 to 10 Hz  with step 1 Hz and it seems a bit weird.

Do you have any tips where the problem could be?

Thanks,

Pavel