Strain and Stress Analysis by Holographic and Speckle Interferometry

Abstract

The first chapter of this book provides an introduction to optical holography and speckle interferometry. While the explanation is sound and thorough it lacks clarity and it is doubtful that it will be understood by any reader who is not an expert in modern optics. The second and third chapters are devoted, respectively, to holographic interferometry and speckle interferometry. The treatment of both topics is rigorous, there are good discussions of experimental errors and experimental techniques and comprehensive bibliographies. Holographic and speckle interferometry, unlike Moirè, do not require any special surface preparation and dispense with the use of gratings, but the fringe patterns produced are difficult to interpret. The mapping out of the displacement field from the experimental data and the derivation of strains are discussed in chapter 4, where the problem presented by steep changes in displacement near strain raisers is addressed. While mathematical techniques for differentiation of experimental data are presented, no mention is made of modern computer software used to automate the process. More than half of the book consists of a number of examples from many different fields: shell structures, fracture mechanics, low cycle fatigue, contact problems, residual stress measurements by the hole drilling method and other practical cases. These examples are taken from the Russian scientific literature. Apart from their interest to the specialist, they illustrate experimental techniques not commonly used in the western world. C Ruiz

A hybrid technique for residual stress analysis through stress function fitting

“…1 shows a sketch and an actual view of the welded specimen. After the hole is drilled the displacements are acquired using the ESPI technique [9,11], typically recording 1024 points from 4 circles centered with the hole, with radius ranging from 1.5mm to 4mm, Fig. 2.…”

Residual Stress Determination by Hole Drilling Combined with Optical Methods

“…Holographic interferometry [39][40][41][42][43][44] appears to have been the first optical method applied with hole-drilling that did not require application of a coating or grating. Figure 6 depicts elements of a basic set-up for holography.…”

Validation of non-linear dynamic simulations through full field optical methods

“…To overcome this drawback, the use of whole field optical techniques, e.g. [1,2], provides a number of significant advances which are emerging from the innovation process. In optical deformation measurement, these advances include digital image correlation and fringe projection techniques.…”