Experimental Study for Buckling and Postbuckling Behaviors of Composite Laminates with Multiple Delaminations

ABSTRACT: The buckling and postbuckling behaviors of composite laminates with mul-tiple delaminations under uniaxial compression are experimentally studied. The through-width multiple delaminations with triangular shape are used to simulate impact damage. A nonlinear buckling analysis from finite element method is also used to predict the buckling loads that are compared with experimental results. The critical delamination growth loads of multiple delaminations are obtained from postbuckling tests. The differ-ence of single delamination and multiple delaminations on buckling behavior and postbuckling behavior is discussed. The results indicate that the buckling loads obtained by the nonlinear buckling analysis are in reasonable agreement with the experimental values. Experiments have proven that short delaminations distributed under the near-surface, long delamination have no effects on the buckling loads. The critical delamination growth loads of single-delamination specimens are much higher than those of multiple-delamination specimens, and the shape of the triangular multiple delaminations can affect the critical delamination growth loads. KEY WORDS: multiple delaminations, buckling, postbuckling, delamination growth, finite element analysis