Modeling the remaining strength of structural composite materials subjected to fatigue

One scheme for reliability-based design that is growing in popularity for civil and naval applications is the load and resistance factor design (LRFD). Our goal in this research is the development of a simulation to predict the remaining strength of structural composites subjected to variable fatigue loading and environmental exposure. The results of this simulation can then be used in LRFD to determine appropriate material “knockdown” factors for use in engineering design applications. The work so far focuses on modeling the response of the material to fatigue damage only. The proposed Monte-Carlo style simulation combines a phenomenological residual strength based life prediction model for composites materials with an empirical stiffness based damage accumulation model. This model is demonstrated using data for two glass reinforced vinyl-ester polymer composite systems. The analysis of these results has led to new insight into how the changes in mechanical properties of these materials exposed to fatigue loading can be modeled.