Abstract
In this study, the fatigue tests of small specimen and a full scale steel structral member were performed to examine the applicability of the X-ray diffraction method for the detection of fatigue damage. The obtained results will be summarized as followes. 1) The half value breadth has changed considerably in accordance with the accumulation of fatigue damage. 2) The change in half value breadth of the actual steel member has shown a simular tendency as the small specimen. 3) The residual stress has changed in a regular manner depending on the applied stress amplitude and the number of stress cycles.