Residual stress distribution in the bovine femoral diaphysis measured by synchrotron

The presence of residual stresses in bone tissue has been noted, and the authors have reported that there are residual stresses in bone tissue. The tensile residual stresses in the bone axial direction on the cortical surface of the bovine femoral diaphyses were measured by X-ray diffraction method with characteristic Mo-Kα X-rays. However, then the residual stresses inside the cortical bone could not be accurately determined. The study here used synchrotron white X-rays obtained from the BL28B2 beam line at SPring-8 and was able to measure the residual stresses in the bovine femoral diaphysis in depth. The measurement positions in the diaphysis specimen were at 1 mm intervals from the outer surface to the inner surface of the specimen in four parts of the diaphysis: anterior, posterior, lateral, and medial. The results showed that the residual stresses in the bone axial direction at the outer cortical surface were tensile and the stresses in the inner positions of the cortical bone were compressive. In the anterior part, the residual stress at the surface was 24.7 MPa. From 2 mm to 10 mm depths inside the diaphysis, compressive residual stresses were measured and the average of these stresses was -9.0 MPa. (author)