Strain rate and temperature effects in polymeric matrices for composite materials

The effect of temperature and strain rate during deformation on the properties and performance of materials has been a long-standing subject of engineering interest, driven by the observation that significant differences in strength, stiffness and life can be induced by these effects. In polymer-based materials, the discussion of such effects usually centers on viscoelastic response and changes in stiffness. The present paper examines subjects that are related to strength, life, and to accelerated testing. Micromechanical effects are identified and discussed, and new concepts are introduced to assist in the interpretation and representation of physical behavior, over ranges of strain rate from impact to quasi-static testing, and temperature from glassy to flow behavior. In this paper, for polymeric matrices over wide ranges of strain range and temperature, theoretical models of strain rate dependent properties and temperature effects are discussed. A quantitative equivalence equation between strain rate and temperature effects is proposed. Finally, comparisons between numerical results and experimental data are shown and the applications / validations of the proposed models are discussed.