Microplane model for stiff foams and finite element analysis of sandwich failure by core indentation

Composite sandwich plates and shells are gaining increasing popularity in engineering practice, due to their high stiffness-to-weight ratio, low thermal conductivity and energy absorption characteristics. Modeling of the structural response of a sandwich member requires knowledge of the mechanical behavior of the materials used for the facings and the core. The paper presents a new constitutive model for closed-cell cellular materials, developed with the microplane approach. The model is then employed in a finite element analysis of three point bending tests of sandwich beams failing by core indentation. Good agreement of the numerical results with the experimental observations is achieved. This proves the new model to be capable of satisfactorily reproducing the mechanical response of cellular materials. (C) 2001 Elsevier Science Ltd. All rights reserved.