Recent Development of Constitutive Models for Strain-Rate Sensitive FRP Composite Materials

The recent developments in constitutive models for strain-rate sensitive Fiber-Reinforced Polymer (FRP) composite materials are of significant importance due to their widespread use in load-bearing structures, such as aircraft. However, they face challenges when subjected to high-velocity impacts, elevated temperatures, and other harsh environmental conditions that must be evaluated before final application. The mechanical response of composite materials to dynamic loading, characterized by high strain rates, is a crucial aspect of their behavior, impacting their structural integrity and safety. Researchers have been investigating the dynamic behavior of FRP composites, employing specialized testing equipment such as the Split Hopkinson Pressure Bar (SHPB) and Split Hopkinson Tension Bar (SHTB). These setups allow for the study of dynamic mechanical properties, including compression and tension behaviors, and are particularly relevant in understanding the influence of strain rates on these materials. Various studies have demonstrated the strain-rate sensitivity of FRP composites, showing that properties like elastic modulus and failure strength are significantly affected by the rate of strain. Furthermore, these materials’ deformation characteristics and failure modes vary under dynamic loading conditions, especially when subjected to different temperature regimes. This chapter provides valuable insights into the dynamic mechanical behavior of composite materials, offering a basis for developing constitutive models to predict their responses under various strain-rate conditions. These models are crucial for improving the design and safety of structures employing FRP composites, such as aircraft, where dynamic loading scenarios are a significant concern.