AbstractA nondestructive technique based on the photoelastic properties of transparent polymers has been used to monitor the distribution of residual stress components in circular rods of poly(methyl methacrylate) (PMMA). The influence of various thermal histories on these stresses as well as on the molecular birefringence has been determined. The technique has been further simplified to obtain the values of maximum tensile and compressive residual stresses with the help of just two photoelastic measurements. The stresses so obtained are within 10 of the values obtained using detailed experimental measurements and their analysis. The simplified procedure is, therefore, suitable for “on‐line” determination of residual stresses in extrusion ind
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