Residual Stress of Thin-Wall Pipe Subjected to Axisymmetric Plastic Expansion Available to Purchase

A straight thin-wall pipe was plastically expanded at one end in the radial direction by inserting a rigid disk. The residual stress measured after withdrawal of the disk at the inner surface in the hoop and in the longitudinal direction shows a strong tensile peak beyond the region where the pipe was directly expanded by the insertion of the disk. The reason why the residual stress reaches its peak at the location far inward of the pipe, not in the region where the pipe was directly expanded, is discussed. From the FE analysis, it is concluded that the residual stress reaches its tensile peak on the inner surface at the plastic region front that was developed during the pipe expansion, and a simple formula for the tensile peak location is proposed. The similarities and differences between the residual stress distribution of the thin-wall pipe and the thick-wall pipe are discussed.