Keywords: composite plates, embedded delamination, higher order shear deformation, post buckling.

Kharazi et al. [1] have investigated the buckling of composite laminates with a through the width delamination by using different plates theories. Ovesy et al. [2] have investigated the effects of the bend-twist coupling terms on the buckling behaviour of the composite laminate with embedded delaminations. Their analytical method is based on the first order shear deformation theory (FSDT).

In the current paper, the compressive post-buckling behavior of composite laminates with embedded delamination is investigated analytically. The delaminated region can be either rectangular or circular. The composite plates and the individual sublaminates which are assumed to be mid-plane symmetric. The plates are subjected to uniform end shortening on the edges parallel to y-axis while the in-plane movements perpendicular to the other edges are not allowed. The boundary conditions of the plate can be considered to be either simply supported or clamped.

For modeling the embedded delamination, the laminate is divided into three smaller regions. For each region the independent polynomial series are assumed as displacements fields by employing Reddy's third order shear deformation theory. These series also satisfy the boundary conditions and the continuity requirements at the junctions. By substituting the assumed displacement functions in the corresponding potential energy expression of each region, the total potential energy of the plate can be evaluated by summation of the potential energies of all regions. The partial differentiation of the energy with respect to each degree of freedom in turn gives a set of nonlinear equilibrium equations. The Newton-Raphson iterative procedure is selected for solving the equations.

The finite element analysis is performed by employing the ANSYS 5.4 software in order to investigate the validation of the results. Within the finite element analysis, the layered eight-node solid elements with three degrees of freedom at each node are used. The agreement between the results of the current method and those of the finite element is very good. It is revealed that by implementing simple and complete polynomials, and thus by using a fairly small number of degrees of freedom, very good results for a rather complicated problem can be obtained. Moreover, it is seen that the load carrying capacity of composite laminates decreases as a result of the presence of delamination.

1

M. Kharazi, H.R. Ovesy, M. Taghizadeh, "Buckling of the Composite Laminates Containing Through-The-With Delaminations Using Different Plates Theories", Journal of Composite Structures, 92, 1176-1183, 2010. doi:10.1016/j.compstruct.2009.10.019

2

H.R. Ovesy, M. Kharazi, M. Taghizadeh, "The Effects of Bend-Twist Coupling Terms on the Buckling Behaviour of the Composite Laminates Containing Embedded Delaminations", in A. Ferreira, (Editor), "Proceedings of the 15th International Conference on Composite Structures", Porto, Portugal, 2009.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £145 +P&P)