Measurement of transient crack-tip deformation fields using the method of coherent gradient sensing

A shearing interferometric method (CGS) is proposed as a viable alternative to currently used experimental techniques for the study of dynamic crack propagation in both transparent and opaque media. CGS is a full-field optical technique that provides real-time fringes representing crack-tip deformation or stress state. The results of the experiments are interpreted on the basis of the conventional singular asymptotic analysis as well as a newly developed transient higher-order asymptotic analysis. The excellent agreement obtained between the experimental results and the higher-order asymptotic analysis clearly indicates that the contribution of the non-singular terms to the total stress and deformation fields is too important to be ignored.