The Effect of Vibration stress relief on Residual Stress of Workpieces

Vibration stress relief (VSR) is a mechanical process used to reduce or redistribute residual stresses in workpieces. This technique involves subjecting the workpiece to controlled oscillatory vibrations that induce a series of plastic deformations, which in turn modify the internal stress distribution.

During VSR, the workpiece is clamped and secured on a vibrating table or platform that applies mechanical vibrations. The frequency and amplitude of the vibrations are carefully selected to match the natural frequency of the workpiece, ensuring that the energy is effectively transferred and resonance is achieved. The vibrations cause the material to undergo cyclic strain, which can result in microscopic changes in the crystal lattice and rearrangement of dislocations.

The primary effect of VSR on residual stress is the reduction of the magnitude and alteration of the distribution of these stresses. The vibrations induce plastic flow that relieves the compressive stresses near the surface and redistributes them to the core of the workpiece. This process can lead to a more uniform and lower overall level of residual stress, which can be beneficial for improving the workpiece's mechanical properties and reducing the risk of failure.

In addition to the direct effect on residual stress, VSR can also lead to secondary benefits such as improved machinability, enhanced dimensional stability, and increased resistance to fatigue and corrosion. However, the effectiveness of VSR can vary depending on factors such as the material composition, the degree of initial residual stress, the geometry of the workpiece, and the specific parameters of the vibration treatment, including the duration, amplitude, and frequency.

To achieve optimal results, it is essential to carefully control the VSR process parameters and to validate the effectiveness of the treatment. This can be done through experimental testing and measurement techniques such as X-ray diffraction, neutron diffraction, or acoustic emission monitoring. Moreover, it is crucial to ensure that the VSR process does not introduce new stresses or cause damage to the workpiece.