A new concept, the equivalent inherent strain g{sub}θ{sup}ep, is proposed for the measurement of axisymmetric residual stresses, based on the inherent strain theory. That is combining the radial and tangential inherent strain components g{sub}r,g{sub}θ into one parameter g{sup}eq{sub}θin computing the axially uniform axisymmetric residual stresses. Based on this concept, the difficulty of estimating the value g{sub}θ{sup}eq g{sub}r is overcome and stress distribution in a long cylinder can be computed by merely estimating g{sub}θ{sup}eq and axial inherent strain component g{sub}z from measured strains in tangential and axial directions. Stress distribution in a thin disk or ring can be simply obtained by estimating g{sub}θ{sub}eq frommeasured strain in tangential direction. The concept was verified by the experiment of measuring residual stresses in a pipe with cladding. A numerical simulation was carried out to demonstrate that the measuring method based on g{sub}θ{sub}eq has boththe convenience of the Sachs method and the high accuracy of the inherent strain method.
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