Study on Application of the cos .ALPHA. Method to Neutron Stress Measurement

Abstract

In order to study on a method of neutron stress measurement using the cos a method, a numerical simulation study was performed comparing with experimental data. The resultant diffraction profiles, which are defined as the distribution of the intensity of diffracted beams in the radial direction from the center of the diffraction ring, were calculated by summing all diffraction profiles which were diffracted at entire depth in the material. The locations of the peak points which were determined using the half value breadth method (or the centroid method) showed dent distribution with respect to the central angle of the diffraction ring even in case of stress free state. Though the stresses calculated by the cos α method showed different values from the initial stresses, the difference between the calculated and initial stresses almost kept constant for different stress level. These misfit stresses can be vanished after correcting original diffraction radius using that in stress free. The results obtained by the present simulation study agreed with those obtained in the previous experiment, which suggests the validity of the method of neutron stress measurement combining both an area detector and the cos α method.