Strain Measurement Near Fatigue Crack in Ultrafine-Grained Steel by Polychromatic Synchrotron Radiation
For engineering components with cracks, it is very important to evaluate the reliability for fracture. The X-ray diffraction method is now widely used to measure non-destructively the loading and residual stresses in crystalline materials. Synchrotron radiation sources provide the X-rays with extremely high intensity as well as a narrow divergence. The high intensity X-rays with a narrow divergence enables stress measurements in a localized region. The strain distribution near the fatigue crack in the steel plate with ultrafine-grained surface layers, called SUF plates, was measured by the polychromatic X-ray from synchrotron radiation at SPring-8. The spatial resolution in the direction parallel to the crack propagation direction was 0.1 mm. The strain distributions at several applied stress levels were determined for six diffraction planes. The measured strain distribution was compared with the result calculated by the FE analysis. The average value of the measured strains for several diffraction planes agreed well with the calculated results.
Y. Akiniwa, K. Akita and H. Suzuki
Y. Akiniwa et al., "Strain Measurement Near Fatigue Crack in Ultrafine-Grained Steel by Polychromatic Synchrotron Radiation", Materials Science Forum, Vol. 652, pp. 290-295, 2010