Abstract
The application limit of the estimation method for mode II interlaminar fracture toughness of composite materials under impact loading, which had been proposed by the authors, was determined by transient finite element analyses varying the dimensions of specimen and profile of incident stress wave. The error in estimating mode II dynamic energy release rate tends to decrease as the maximum acceleration at the central loading point decreases. The error can be reduced remarkably by calculating the energy release rate from the surface strain of specimen. The application limit of the proposed method was evaluated to be 4-400sec-1 in shear strain rate for the specimens of 1-5mm in thickness and 60mm in bending span, assuming the critical energy release rate (fracture toughness) to be 1500J/m2 and the allowable error to be 10%. This limit is much higher than those of the conventional methods (e.g. servohydraulic testing instrument, drop weight impact test, split Hopkinson system using step incident stress wave).
