RANDOM-DAMAGE FINITE-ELEMENT FOR STUDYING MICROMECHANICAL FAILURE MECHANISMS IN ADVANCED COMPOSITES

A finite element procedure for simulating damage progression in an adv anced composite material loaded in fiber-direction tension has been de veloped. The eight-node, eight-degree-of-freedom element is used to mo del a small cell of a composite, the properties of which were determin ed from micromechanical simulations. A Monte Carlo simulation techniqu e is used in the micromechanical simulation to characterize the random degradation paths that this cell can follow when subjected to axial t ension. These results are synthesized using a neural network to effici ently determine the expected value and variance of the degradation of the random-damage finite element given the current state of the elemen t. Results from failure simulations of Kevlar/expocxy composites are p resented and compared to experimental results.