Load measurements can be severely influenced by dynamic effects and become unreliable at high rates. Hence, the use of load-independent analysis methods can offer significant advantages over those requiring load values to be known. However, in these alternative schemes, the accuracy of load-line displacement and crack length measurements become highly important for the accurate determination of G_(IC) values. These parameters can be measured accurately by capturing the fracture event using high rate video imaging. The adhesive fracture energy decreased with increasing test rate and also the mode of fracture changed from stable to unstable (stick-slip type) crack propagation. Substrate thickness effects were insignificant at test rates of up to 0. 1m/s but became considerable at higher rates.
展开▼
