Investigation of the Effects of Constitutive Equations on the Free Vibration Behavior of Single-Celled Thin-Walled Composite Beams

An investigation of the free vibration behavior of thin-walled composite box-beams is carried out by considering different assumptions in the constitutive equations. Within the present model some non-classical effects, such as restrained warping and transverse shear, are incorporated. Free vibration results are validated against experimental and numerical results, which are available in the literature. The natural frequencies obtained based on the different assumptions of constitutive equations are compared, and it is revealed that these assumptions play an important role in the proper treatment of the free vibration behavior of torsion-bending coupled composite beams. The results obtained based on the proposed constitutive equations are demonstrated to have a good agreement with the finite element results as far as the lower natural frequencies of the beams are concerned.