Procedure for detecting the shape and size of defects on metallic substrates under composite repairs using shearography.

This paper presents a numerical-experimental procedure to characterize through-holes with arbitrary shapes present on metallic substrates under composite material sleeves using pulsed laser shearography and dynamic excitation combined to the finite element method. The so-called fitting process consists of matching experimental and numerical results in order to determine the shape and dimensions of the holes under the composite repair, or even quantify defects between layers of the composite laminate. The results show that the technique is capable of characterizing, in the worst case, the geometry of a hole with 83% accuracy and its respective area with a maximum error of approximately 20%.

Robust method to improve the quality of shearographic phase maps obtained in harsh environments.

This paper presents a new approach to improve the quality of shearographic phase maps acquired in a harsh environment. During in-field nondestructive inspections, the presence of higher disturbances, mainly vibrations, can introduce unknown phase deviations in the sequence of shearographic images. This paper presents a different approach that combines the N-dimensional Lissajous algorithm [Int.

Radial phase variation computing: a tool to improve flaw detection in optical diagnosis by shearographic images.

Shearography is an optical and nondestructive technique that has been largely used for damage detection in layered composite materials where delaminations and debondings are found to be among the most common flaws. Shearography detects derivative of the displacements. It is a relative measurement in which two images are recorded for different loading conditions of the sample.