Prediction of the Effect of Craze Damage on Apparent Elastic Properties of Polystyrene by FEM

Craze damage, caused by excessive tensile loading, can reduce the apparent elastic strength of polymeric materials. Due to the complexity of the problem, very few attemps have been made to model the effect of crazes on the elastic properties of polymer. In this paper, the effect of craze damage on the elastic properties of polystyrene (PS) has been investigated from a meso-mechanics approach using finite element method (FEM). FEM is applied to an idealized craze model in order to estimate the apparent elastic properties of a craze damaged PS. Under three loading schemes, the elastic properties E1, E2, G12, and v12of the craze damaged PS are predicted. The finite element software, μFIELD version 2.20 from Rockfield, is used for predicting the effect of craze damage. The predicted results indicate that the apparent elastic properties of the craze damaged polymer are governed by the craze density and length. A series of tests is done to determine the apparent properties of PS under different degree of craze damage. The FEM prediction is found to be in good agreement with the experimental result.