Published in Comput. Methods Appl. Mech. Engrg. Vol. 30 (2), pp. 133-149, 1982
An isoparametric finite element tor the analysis of multi-layer composite materials is presented. Several linear and nonlinear stress-strain relations are discussed. Special attention is given to the composite materials with different moduli in tension and compression, for which a new mathematical model is presented and tested.
Different failure criteria for the matrix degradation are incorporated in the element and several post-degradation behaviors are also considered.
Finally we discuss the role of the Newton-Raphson method in composite materials, especially in the presence of geometrical nonlinearities.