POSTBUCKLING ANALYSIS OF MULTIPLY DELAMINATED COMPOSITE PLATES

This paper presents an elastic post-buckling analysis of an axially lo aded beam-plate with two central across-the-width delaminations locate d at arbitrary depths. The analysis is based on the nonlinear beam equ ations, combined with the appropriate kinematic continuity and equilib rium conditions. A perturbation technique is employed, which transform s the nonlinear equations into a sequence of linear equations. An asym ptotic solution of the post-buckling behavior of the plate is thus obt ained. It is shown that with two delaminations, both the maximum defle ction and the internal load of the first buckled (top) subplate increa se as the external load increases. Of particular interest is the redis tribution of load among subplates, which keeps the increase rate of in ternal load of the top buckled subplate much less than that of the ext ernal load. In other words, the load of the buckled subplate is close to the critical value even though the externally applied load is much larger than the critical load In addition to the two-delamination conf iguration, a single delamination case is studied based on the present approach in order to verify the accuracy of the method. Also, a compar ison with available finite element results is performed.