e-Journal of Non-Destructive Testing 11, 2006


G. Wimmer, C. Schuecker, H.E. Pettermann

Austrian Aeronautics Research (AAR),
Institute of Lightweight Design and Structural Biomechanics,
TU Wien, Vienna, Austria

Abstract - Delamination in fiber reinforced laminated composite structures is analyzed. The numerical simulation of delamination is divided into creation of a starting delamination and delamination growth. The starting delamination is predicted by a stress based failure criterion developed by Puck. Growth of the starting delamination is modeled by the Virtual Crack Closure Technique. A curved laminate is analyzed to demonstrate the proposed simulation procedure. A linear finite element analysis is performed to predict the starting delamination, whereas nonlinear analysis are required for the simulation of delamination growth. The effect of the size of the starting delamination is studied and a critical size is found. From the simulations of the growth of various starting delaminations the maximum bearable load of the structure is predicted. Moreover, structures containing initial delaminations were analyzed, yielding conditions for crack growth stability. For the verification of the proposed simulation procedure, cohesive zone elements are used and the same results are achieved. However, the proposed simulation procedure is computationally markedly cheaper than the use of cohesive zone elements.