Abstract
A new technique utilizing the X-ray diffraction is proposed to estimate the circumferential distributions of residual stresses on convex/concave cylindrical surfaces. This technique requires neither tilting X-ray beams in the circumferential direction in which the X-ray incident angle tends to be limited nor adjusting the normal of the irradiation area to the reference axis of the ψ angle. The circumferential distribution of the circumferential stress and that of the axial stress are estimated from the geometrically modulated diffraction angles at ψ=0 (deg) and the geometrically modulated axial stresses measured at the inclined points by performing the stress measurement on multiple inclined points of the cylindrical surfaces under the configuration of the axial stress measurement using the iso-inclination scanning method. This estimate technique was applied to two specimens of round bars; one has circumferential distributions of the residual stresses, and the other has almost uniform stresses. The distribution functions of the residual stresses were expanded to a couple of Fourier series, and the coefficients of them were determined so as to satisfy the geometrically modulated quantities mentioned above. The estimated distributions of the residual stresses were in practically good agreement with the actual ones.
