Natural Frequencies and Mode Shapes of Composite Cylindrical Delaminated Shells by Finite Element

Abstract

An elaborate review of the literature of composite shells reveals that vibration characteristics of delaminated shell roofs have received very limited attention. Hence in this article dynamic behavior of delaminated composite shallow cylindrical shells with corner-point supported, simply supported and clamped boundary conditions is analyzed by finite element method using eight-noded isoparametric shell element. To ensure compatibility of deformation and equilibrium of forces and moments at the delamination crack front, a multipoint constraint algorithm is incorporated, which leads to unsymmetrical stiffness matrix. Stacking sequence, position and extent of delamination area are varied to compare the performances of delaminated cylindrical shells against those with no damage. The results are carefully observed and a set of conclusions is presented at the end of the article.