Scattered light three-dimensional photoelasticimeter - Application to a blade of a compressor

A three-dimensional photoelasticimeter based on the Rayleigh principle of light scattering is described. A laser beam polarized by a prism with direction of polarization controlled by a rotating half-wave plate illuminates the model, and the elliptical birefringent is deduced from three parameters of the signal. The photoelasticimeter was used to determine the maximum shearing stresses in a compressor blade with frozen stresses, and agreement was satisfactory with the results obtained by the stress slicing method.