共振法による薄板の音弾性応力測定

概要

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The resonance method is studied for measuring residual stresses in thin plates of aluminum 2024-T361. The resonance frequency is a function of the plate thickness and the elastic wave velocity, both of which vary with the stress because of the Poisson effect and the acoustoelastic effect. PZT elements of the thickness-shear mode are used to obtain the resonance frequencies for the polarizations in the principal stress directions. Their difference, being equivalent to the acoustic birefringence, is found to be linearly dependent on the uniaxial stress up to 300 MPa. The frequency shift induced by mounting the PZT element can be minimized by choosing the mode whose resonance frequency is closest to that of the transducer alone. The two-dimensional stress field in welded plates is then measured by scanning and rotating the transducer. The obtained principal stress difference coincides with the measurements by the conventional sing-around method and the destructive strain gauge method. The accuracy is about ±10 MPa.
社団法人日本機械学会の論文
1992-02-25