A Study on the Accuracy of Estimated Residual Stresses by the Existing Measuring Methods

概要

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In order to measure three dimensional residual stresses, Sachs, and Rosenthal and Norton have been already proposed their methods which are well-known. These methods use the analytical solutions or the approximated equations as the basic relations by which residual stresses are calculated from measured data. There is a question on the basic assumptions made in the Rosenthal-Norton method and there are examples that the Sachs method is applied beyond the limiting conditions. In this paper, validity and limits of application of these methods were investigated with the aid of the finite element method and the following information was obtained. (1) The Resenthal-Norton method can not be applied generally in three dimensional stress state because it was assumed in the method that the relaxed stresses distribute linearly in the direction of thickness at the first step (removal of a block). (2) The Sachs method gives the correct result if residual stresses are uniform in the axial direction and of rotational symmetry. In cases where either of two assumption is not satisfied, this method can not be applied. (3) A general theory of measuring method of three dimensional residual stresses has not been formulated yet except by the authors.