背面回折X線像を用いた応力測定装置の開発

抄録

The X-ray stress measurement based on sin²ψ method has been widely adopted. This technique is not entirely efficient, because it is necessary to measure each diffraction profile one after other at five and more incident X-ray angles. On the other hand, stress measurement based on cosα method was proposed using X-ray film as detector. In this method, the stresses are determined from Debye-ring obtained at a single X-ray incident angle with high efficiency. However, it has the problem in this accuracy on stress determination. In this study, a new stress analyzer with sixteen position sensitive proportional counters (PSPC) radially arranged for incidence X-ray was developed. We examined to determine the plane stress components by multi-regression analysis using sixteen diffraction angles on a Debye-ring. As a result, stress components of σ_x and τ_xy were measured with sufficient accuracy. However, a stress of σ_y had large dispersion, because of low strain sensitivity in the y direction. Moreover, it was clarified that σ_y had pseud-multicollinearity on multi-regression analysis. The accuracy of σ_y value itself could not be improved, though an analysis to eliminate an effect of pseud-multicollinearity was carried out. In this paper, we proposed the new method to determine the components using two Debye rings obtained by X-ray incidences in both x and y directions. We tried to measure the residual stress components in the butt welded joint using the method. As a result, it was confirmed that the stresses, σ_x and σ_y, were obtained in the sufficient accuracy, and that the shear stress, τ_xy, was arising near the bond in the welds.