A study on dynamic fracture toughness of composite laminates at different temperatures

The fracture toughness of glass-cloth/epoxy laminates has been determined under different temperatures and strain rates by means of the WEK fracture mode. To determine the parameters of WEK model, two groups of experiments must be conducted. One is the tensile experiment of smooth specimens (there is not a crack). Another is the tensile experiment of specimens with a crack. The tensile strengths are measured and the certain curves are drawn by means of the two experiments. Then, the characteristic length a for the laminates is obtained. Finally, from the values of a, the fracture toughness of the laminates is determined. The experimental results show that there exist clear effects of temperature and strain rate for the fracture behaviour of glass-cloth/epoxy laminates. Some problems of failure process and damage for the laminates have also been discussed. It is found that different damages are formed in the laminates under different temperatures and strain rates.