Dynamic stability analysis of delaminated composite beams in frequency domain using a unified beam theory with higher order displacement continuity

摘要

In this paper the dynamic stability behaviour of single delaminated composite beam is investigated using higher order shear deformable beam theories. The system is discretised by the finite element method and the mass, material stiffness and geometric stiffness matrices are formulated by means of higher order displacement continuity in the intact part. The natural frequencies and critical buckling forces are determined for various beam theory orders and delamination lengths and positions. Furthermore, using the multi frequency method the dynamic stability properties of the system are calculated in frequency domain. Based on the stability analysis the sufficient beam theory order and multi frequency method's corresponding truncated matrix determinant order are determined in order to achieve the desired accuracy on the observed parameter plane. The results indicate that the dependence of the natural frequencies and buckling forces is negligible on the order of the applied beam theory. In contrast the former quantities are significantly influenced by the delamination length and position. Finally, it is shown that the dynamic stability diagrams and the boundary frequencies of parametric instability do not depend on the delamination length and position from the engineering point of view.