Stresses and Deformations Arised from Uniform Inherent Strains in Thin-Walled Pipes

Abstract

Stresses and deformations arised from the uniform inherent strain existing in a rectangular region on the surface of a thin-walled pipe are obtained by applying the Green function, introduced by Shirakawa, for a non-stationary thermoelastic problem in a thin circular cylindrical shell. The results are developed to an analytical model for calculating residual stresses and deformations due to axial and/or circumferential welds of a pipe, and the parameters determining the residual stresses and deformations such as radial deformations, change in curvature are derived analytically for both axial and circumferential welds. In case of axial weld, the parameters are βx=√a/h⋅a/l and θ₀/π, where a, h and l are the mean radius, thickness and length of the pipe respectively, and θ₀ is the half angle of the region of the inherent strain in circumferential direction. In case of circumferential weld, the parameters are β_θ=l/√ah and 2l₀β_θ/l, where lo is the half width of the region of the inherent strain in axial direction.