STRESS ANALYSIS BY HOLOGRAPHIC INTERFEROGRAM COMPARISON

摘要

The structural integrity of a load bearing structure is periodically evaluated by recording on the same holographic recording medium two successive holograms of the structure while the latter is in two different stress conditions, respectively, to produce a holographic interferogram which may be reconstructed to create a deformation fringe pattern representing the deformations in the structure resulting from the change in the stress conditions. This deformation pattern is compared with an earlier deformation pattern of the structure resulting from the same stress conditions to determine differences, if any, between the two patterns, such differences being indicative of a reduction in the stiffness and hence structural integrity of the structure due to weakening of the latter by fatigue damage, stress corrosion cracking, and/or other causes.