19.10 : 円形シャフトの残留応力

In elastoplastic materials, residual stress can develop when the material undergoes plastic deformation due to high shearing stress or large strains.

When the external loading is removed, the internal stresses sustained within the shaft material are known as the Residual stresses.

Plotting the torque versus angle of twist diagram, it can be shown that the angle of twist does not return to zero when the torque is removed. A straight line represents the unloading of the shaft.

The residual stresses in elastoplastic material are obtained by applying the principle of superposition.

First, the stresses due to the applied torque are considered in the loading phase, and then the stresses due to the equal and opposite torque applied to unload the shaft are considered. The distribution of residual stresses in the shaft is obtained by adding these two groups of stresses.

Plotting stress versus the radial distance, it can be observed that some residual stresses share the same direction as the original stresses, while others are in the opposite direction.