Stochastic modeling of damage evolution in composites under environmental ageing

Stochastic modeling of damage evolution in composites under environmental ageing

R. Rahman, A. Haque, Z. Wu

Journal of Engineering Mathematics

April 2013, Volume 79, Issue 1, pp 153-166

Abstract

A mathematical model
is proposed for predicting damage evolution and stiffness degradation in
composite materials under environmental ageing. Environmental
parameters such as moisture, temperature, and ultraviolet (UV) radiation
cause hygrothermal loads on the structure, which leads to damage
evolution. The present work establishes a constitutive model for
treating the damage density as a random variable. A forward stochastic
differential equation (FSDE) is proposed to predict the damage density
evolution. Damage nucleation and annihilation rates are taken into
consideration in terms of Brownian motions. A second-order damage tensor
is developed using the solution of the FSDE. The damage tensor is
incorporated into the constitutive model for predicting the elastic
moduli. Finally, the proposed model is verified against experimental
observations under certain hygrothermal conditions.