Measuring method of residual stress distribution, calculating method of same, and program

A measuring method for measuring a residual stress distribution at a cross section between a first metal part and a second metal part of a metal member, the measuring method comprising:

• the step of cutting the metal member at the cross section in such a way that the first metal part is cut off and becomes a first metal piece, and the second metal part is cut off and becomes a second metal piece;
• the step of measuring a shape of a cut-surface of the first metal piece or a shape of a cut-surface of the second metal piece;
• by using an analytical model in which a cut-surface is interpolated to the cross section of the metal member, the step of calculating a residual force vector that is a sum of a load vector acting on the first metal piece at the cut-surface and a load vector acting on the second metal piece at the cut-surface;
• the step of calculating, as a modified displacement vector, an amount of movement at the cross section by interpolating the residual force vector as a forced load to the cross section of an analytical model of the metal member;
• by using an analytical model having the shape of the cut-surface of the measured first metal piece or an analytical model having the shape of the cut-surface of the measured second metal piece, the step of modifying the shape of the cut-surface of the first metal piece or the shape of the cut-surface of the second metal piece on the basis of the calculated modified displacement vector;
• and
• by using the analytical model in which the shape of the cut-surface of the first metal piece is modified or the analytical model in which the shape of the cut-surface of the second metal piece is modified, the step of calculating a residual stress distribution at the cross section by interpolating a forced displacement to the analytical model.