Analytical modeling of the ballistic impact performance of glass fabric- epoxy composites at low temperatures

Environmental temperature is one of the factors which influences the performance of glass fabric reinforced polymer (GFRP) composite in armor applications. In the present work, an analytical model was developed for the GFRP composite which takes into account the strain rate dependency and temperature effects of the matrix material. The model predictions for the ballistic limit were compared with the data obtained from ballistic impact experiments performed at temperatures ranging from-35 degrees C to +30 degrees C. Results from the analytical model indicate that the ballistic limit velocity of GFRP composites increases with decreasing temperature and a major part of the projectile kinetic energy at the ballistic limit was observed to be dissipated in the form of strain energy and shear plug formation. The shear plug thickness at the ballistic limit increased at lower temperatures indicating a shift in failure mechanism towards shear rather than tension with reducing temperature. Further observations from the modeling results were that the inclusion of rate dependency effects of the matrix did not lead to a significant change in the ballistic limit predictions at lower temperatures.