Automated analysis in digital speckle shearing interferometry using an object step-loading method
ABSTRACT Automated analysis in digital speckle shearing interferometry using the conventional two-frame differencing method is hindered by phase unwrapping errors and unresolved fringe patterns due to excessive object load. An object step-loading method with the ability to surmount these limitations is proposed and demonstrated. An added advantage of the proposed method is its ability to yield the entire slope versus load history within one loading cycle.
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ABSTRACT: Sensitive, computer-aided retardation phase measurement methods suffer from the problem of discontinuity, which, in turn, hinders faultless phase unwrapping for stress determination in photoelasticity. An object step-loading method is introduced in this paper to overcome such a problem. One advantage of the technique is that the entire loading-to-stress history is computed. In this paper, the theoretical aspects related to implementation of the object step-loading method in computer-aided photoelasticity are outlined, and experimental verification is performed on a birefringent model subjected to compressive loading by comparing stress values with those computed using the theory of elasticity.Experimental Mechanics 05/1997; 37(2):137-141. · 1.55 Impact Factor