Mechanical analysis of square shaped PMMA using reflection photoelasticity

Abstract

This research involves an application of reflection photoelasticity used to analyze stressed samples. The poly(methyl methacrylate) (PMMA) had a rectangular shape 2.5 × 2.5 × 0.6 cm and was compressed by hydraulic press system. The observation of a stressed sample using reflection photoelasticity showed isochromatic and isoclinic fringe patterns. We adjusted the polariscope to determine the photoelastic parameters, namely fringe order, angle principal stress and strain value, which were used to calculate the stress-strain based on calibration, shear difference method and stress-strain optic law. It was found that maximum normal stress (y-direction) and strain values were at contact area and decreased to the edge and center along horizontal and vertical direction of sample. Shear stress depended on multiple of fringe order and sin2θ. It was zero along center of vertical and horizontal direction of sample.