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This work focuses on the mechanical performance of E-glass/fire retardant bisphenol A epoxy vinyl ester composites under compressive loads that are exposed to a one sided heat flux. The goals of the experimental work were to adequately characterize lamina off axis stiffness response at elevated temperatures, and to characterize the response of laminate specimens exposed to combined thermal and mechanical loading.A unique test was developed that exposed laminate coupon specimens to a one sided heat flux and mechanical load.Experiments were conducted in an effort to characterize the effect temperature has on the reversible off axis stiffness; this data would be used in the modeling of the laminate specimens exposed to the combined loading scenario. Modeling techniques that predict the time to failure and the strain history of vinyl ester samples subjected to a simultaneous compressive and thermal load is developed and compared against experimental data. Only reversible material property changes that are a function of temperature are accounted for in the modeling efforts. The modeling approaches agree reasonably well with experimental results that do not include the effects of elevated temperature creep.

Absrtract. In this paper, a framework is presented for the modeling of the response of structural composites subjected to combined mechanical loading and fire. An emphasis is placed on the response of composites at temperatures below the decomposition temperature, where the viscoelastic response of the composite material becomes important. Material property characterization results are presented for an E-glass reinforced vinyl ester composite typical of that used for naval ship applications. Time-temperature equivalence is used in a compression strength model to predict the time to failure of composites subjected to isothermal compression loading (compression creep rupture failure). These predictions are compared with experimentally determined times to failure with good agreement. In particular, shift factors obtained from shear compliance testing are able to collapse the compression creep rupture data at different temperatures, indicating that viscolelasticity is the dominant mechanism driving the failure. This model is combined with a standard diffusion model for heat transfer in the composite to predict the time-dependent failure of composites subjected to simultaneous one-sided heat flux and compression loading. Predicted times to failure are compared with experimental results with good agreement.

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