1977 年 26 巻 280 号 p. 6-10
The strength of large structures such as vessels, slips or bridges depends mostly not only on the residual stress caused by welding but also on constrained stress, and therefore a non destructive stress measurement on a real object is demanded. Based on the experience that one of the authors previously made X-ray stress measurement of ship construction, authors newly developed a compact type of X-ray diffraction stress analyzer which adopts a modified side inclination method and enables the stress measurement at the corner of structures. This analyzer has also such features as an incident X-ray oscillation mechanism for the stress measurement of coarse grained materials, a direct charge system for making counting circuits small and 5×5mm2 large focal spot X-ray tube which is useful in side inclination method.
The relation between the measured stress σx' and the true stressσx is theoretically calculated as follow.
The error of σx' is negligibly small, and is found to be comparable to that of the data by using a conventional type of apparatus, based on the experimental results on S15C and S40C heat-treated specimens under uniaxial stress. Goniometer setting error under ±2mm also does not increase the error in X-ray stress measurement.