Mohsen Fatahi, Islamic Azad University; Foad Saadi, Islamic Azad University

Buckling and post-buckling analysis of composite laminated structures having delamination were studied numerically. The analysis was performed using the generalized differential quadrature method. Several ones and two-dimensional models were developed and showed to be capable of predicting the buckling and post-buckling responses of composite beams and plates. Prediction of the buckling strength of the delaminated composite beams and the examination of the influencing factors were coming out by employing several models. The effects of the shear deformation and the bending-stretching coupling were added by incorporating a shear deformation beam theory. The accuracy and efficiency of the proposed method were evaluated through several case studies. In addition to the effect of shear deformation, bending stretching coupling, the influence of material properties, lamination sequence, and fiber orientation through the thickness and through the length locations of delamination on buckling and post-buckling responses were investigated. For the post-buckling analysis, the GDQM combined with an arc-length strategy was used to model the post-buckling analysis of composite beams having single or multiple delaminations. The nonlinear Von Karman strain-displacements and the exact curvatures were used to formulate the problem. The results show that the GDQ technique can be used as a powerful, reliable, accurate and efficient numerical tool in assessing the buckling and post-buckling responses of delaminated composite structures.  Besides the excellent quality of results that obtained through GDQM, the method is relatively simple to formulate and it requires less effort to implement. Furthermore, the method consumes relatively less effort, both in terms of computational time and also in the user effort in setting up a problem.
Keywords: Buckling and post-buckling, Composite Structure, GDQM, delamination