Abstract: In this Paper,according to Euler beam theory,Timoshenko beam theory and higher order beam theory,the inherent vibration characteristics of elastic beams are compared with that of composite laminated beams.The patterns of mode shapes are divided into two types,in one of the two types,the bending gradients are relatively more than the shear,in the other one,the shear gradients are more,and the latter type consists of several pure shear mode shapes.It is founded that many order frequencies and mode shapes rela...