New numerical method for the photoelastic technique

Abstract

The objective of this research is to find new equations for a novel phase-shifting method in digital photoelasticity. Some innovations are proposed. In terms of phase-shifting, only the analyzer is rotated, and the other equations are deduced by applying a new numerical technique instead of the usual algebraic techniques. This approach can be used to calculate a larger sequence of images. Each image represents a measurement of the stresses present in the object. Every photographic image has errors and random noise, but the uncertainties due to these effects can be reduced with a larger number of observations.

3D reconstruction based on photoelastic fringes

“…The isochromatic phase map calculated by Equation ( 6) and Figure 3 For a polycarbonate disk under diametric compression, the exact value of the stress field in the disk can be calculated by 49,50 :…”

The Photo‐Elastic Constant of Silicon Reviewed in Experiment and Simulation

“…[19] Descriptions of the methodology for checking material properties-sometimes called Brazilian test-and for calibrating photo-elastic experimental set-ups can be read in older textbooks [20][21][22] but also repeatedly, for instance, in recent articles. [23,24] The application to silicon wafers was reported-to the best of our knowledge-in the past years only once. [25] The special procedure using SIRD for calibration has been presented until now only in brief.…”

“…The diametrical loading of cylindrical samples has been already discussed by Hertz in 1883 . Descriptions of the methodology for checking material properties—sometimes called Brazilian test—and for calibrating photo‐elastic experimental set‐ups can be read in older textbooks but also repeatedly, for instance, in recent articles . The application to silicon wafers was reported—to the best of our knowledge—in the past years only once .…”