Nondestructive stress-strain technique

This photoelastic stress analysis is a technique for the nondestructive determination of stress and strain components at any point in a stressed product by viewing a transparent plastic product. If not transparent, a plastic coating is used such as certain epoxy, polycarbonate, or acrylic plastics. This test method measures residual strains using an automated electro-optical system. 

Different nondestructive techniques are used to evaluate the stress level in products. They can predict or relate to potential problems. There is the popular electrical resistance strain gauges bonded on the surface of the product. This method identifies external and internal stresses. The various configurations of gauges are made to identify stresses in different directions. This technique has been extensively used for over half a century on very small to very large products such as toys to airplanes and missiles. 

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