Fundamental principles of neutron residual stress measurements

Residual stresses have been one of the key factors in developing new materials and structures. Neutrons can penetrate a thousand to ten thousands times deeper than the conventional X-rays, and can be utilized to measure the stress in the interior of the material. In this article, the fundamental concept of the stress states in the engineering component and the relationship between the stress and the strain were explained. Some recent developments of the stress measurement were reported. (author)