Adiabatic heating and damage onset in a pultruded glass fiber reinforced composite under compressive loading at different strain rates.

Damage onset and adiabatic heating of a pultruded Glass Fiber-Reinforced Plastic (GFRP) composite was investigated using compression tests at low, intermediate and high strain rates (10 ⁻³ s ⁻¹, 1 s ⁻¹ and 10 ³ s ⁻¹). Optical and infrared (IR) cameras monitored the specimens during testing, so that the mechanical response, damage onset, and damage evolution were obtained along with the adiabatic heating of the specimen due to plastic deformation and fracture. The results revealed clear strain rate effects on stiffness, strain softening and damage initiation. The simultaneous optical and IR imaging allowed quantitative description of thermomechanical response of the material and studying the formation and propagation of shear localizations and their temperature history. The maximum temperatures in the fracture zones exceed 80 °C at the strain rate of 10 ³ s ⁻¹. Scanning Electron Microscopy (SEM) was used to identify the micro-scale crack paths at different strain rates. The findings allow more exact numerical predictions and design of tubular GFRP pipes for impact applications.