Figure 8.

An illustration of residual stress–strain measurement using the sin²ψ method. When bone tissue deforms, the interplanar spacing d of the mineral crystals in the tissue changes. The angle of inclination ψ is defined as the angle between the normal direction of the specimen surface and the diffracted lattice plane. The interplanar spacing in lattice planes under tensile stress is larger in the ψ=90° than in ψ=0° direction. The relation between d and ψ is affected by the stress intensity. (Reprinted with permission from [77] © 2010 ASME.)