Progressive failure analysis of a composite shell

The objective of this research is to determine the physical response includ ing material failure of a thin, curved composite panel designed to resist t ransverse loading. The cause of the material failure, in the form of fiber, matrix and/or delamination failure, will be determined through failure cri terion based on nonlinear movement using a finite element analysis techniqu e. The finite element analysis technique known as the simplified large disp lacement/rotation (SLR) theory allows for large displacements but assumes s mall to moderate rotations (A.N. Palazotto, S.T. Dennis, Nonlinear Analysis of Shell Structures, American Institute of Aeronautics and Astronautics, I nc., Washington, DC, 1992). Third-order shell kinematics, defined relative to the shell mid-surface, allow for the characterization of in-plane and tr ansverse shear effects, while neglecting the direct transverse effects. Dat a generated using the SLR theory both with and without the addition of prog ressive failure criteria, will be compared with previously published experi mental data, noting where the SLR theory diverges from the experimental res ults. The inclusion of the Hashin failure criterion will provide a more rea listic representation of the total physical response of the shell (Z. Hashi n, J. Appl. Mech. 47 (1980) 329-334). The criterion will investigate the sh ell, from initial loading, to further progressive composite failures. As th e composite shell fails, the constitutive relations, or shell stiffness wil l be reduced. Results of the analytic comparison with the experimental data indicate that the SLR theory overpredicts the stiffness of the shell wheth er considering or not considering failure criteria. Results generated for t he case incorporating a progressive failure criterion are closer to the exp erimental data because of the reduced stiffness due to failure as the defle ction increases. Published by Elsevier Science Ltd.