Analysis of combined moire and laser speckle grating methods used in 3-D crack tip deformation measurements.

The paper provides analyses for two optical schemes developed for mapping 3-D crack tip fields in ductile materials. The first scheme combines the in-plane moire method with the projection moire method to determine all three displacement components simultaneously. In the second method, we combined onebeam laser speckle photography with the projection moire method to measure 3-D deformation fields. The experimental results obtained using these methods are presented.