Stiffness analysis of polymeric composites using the finite element method

The ability to predict the mechanical behavior of polymer composites is cru cial for their design and manufacture. Extensive studies based on both macr o- and micromechanical analyses are used to develop new insights into the b ehavior of composites. In this respect, finite element modeling has proved to be a particularly powerful tool. In this article, we present a Galerkin scheme in conjunction with the penalty method for elasticity analyses of di fferent types of polymer composites. In this scheme, the application of Gre en's theorem to the model equation results in the appearance of interfacial flux terms along the boundary between the filler and polymer matrix. It is shown that for some types of composites these terms significantly affect t he stress transfer between polymer and fillers. Thus, inclusion of these te rms in the working equations of the scheme preserves the accuracy of the mo del predictions. The model is used to predict the most important bulk prope rty of different types of composites. Composites filled with rigid or soft particles, and composites reinforced with short or continuous fibers are in vestigated. For each case, the results are compared with the available expe rimental results and data obtained from other models reported in the litera ture. Effects of assumptions made in the development of the model and the s election of the prescribed boundary conditions are discussed. (C) 2001 John Wiley & Sons, Inc.