Effect of Resin Viscoelastic Behavior on High Strain Rate Impact Performance of Fiber Reinforced Composites

The influence of measurement temperature on the high velocity (>100 m/s) impact performance was investigated for a model thermosetting resin composite system. Plain weave S-2 glass composite panels were fabricated using VARTM and an epoxy resin cured with a polyetheramine curing agent. Overall, the energy absorption for the composite remained approximately constant over a broad testing temperature (T) range. The damage area caused by high-strain rate delamination, however, showed remarkable dependence on the T-Tg. The damage area was high in the glassy state (low T-Tg values) and decreased as the resin traversed its Tg into the rubbery region. Impacted samples showed that an increase in back face deflection correlated to lower damage areas and enabled more energy absorption. These results illustrate the critical importance of the temperature dependent viscoelastic behavior on the impact properties of composites.