Showing papers by "Baldur Eliasson published in 1977"

Quantitative Strain and Stress Determination from Holographic Interferograms.

Abstract: : The basic problems of quantitative determination of mechanical strain through holographic interferometry are discussed. A solution based on the calculation of local derivatives of the holographically recorded surface displacements is described. This method uses essentially heterodyne holographic interferometry for the quantitative determination of the surface displacement from the fringe pattern in the image plane. With this technique the interference phase can be measured with an accuracy and reproducibility of + or - 0.3 deg at any point in the fringe pattern, corresponding to an interpolation of better than .001 of one fringe. Numerical examples are given for the sensitivity and accuracy of surface strain measurements and the determination of bending and torsion. Experimental results for bending and torsion of arbitrarily curved and twisted space beams, such as turbine blades, are reported. Accuracy and agreement with theory are within a few percent. (Author)