Numerical Simulation Of Ultrasonic Impact Treatment On Residual Stress Filed Of Aluminium Alloy

The UIP (Ultrasonic impact peening) technology is a kind of effectivedeformation strengthening process, but the mechanism is very complex andoptimization of technological parameters is greatly difficult. In this paper, accordingto the impact process, the effects of impact needle speed on the stress distribution inplastic deformation area of the metal specimens were studied. And the method offorecasting the plastic deformation layer and compression residual stress depth bymeasuring the maximum speed of impact needle was proposed.The finite element software ABAQUS was used for simulating the process ofimpacting Aluminium. Variation rules of impact, and stress distribution and plasticstrain were obtained. By comparing the relationship between these, stress distributionand plastic strain field should be determined by the maximum impact speed. Thestress simulation results of multiple peening with the maximum impact speed weresimilar to the experiment results, which showed that the simulation of peening is valid.The mechanism of UIP process was explained.The treatment results of different UIP technological parameters (amplitude ofamplitude transformer, diameter and length of impact needle) were obtained by bothsimulation and experiments. The increase of amplitude led to the improvement of themaximum impact speed, plastic deformation degree, compression stress depth, surfacecompressive stress and hardness growth ratio. The results were on the contrary bydecreasing diameter and increasing length of impact needle. The results of simulationand experiments were nearly the same, so it could be a new method of UIPtechnological parameter optimization by simulation.By observing the impact needle motion by high speed camera equipment, theactual maximum impact velocity was lower than the result of the simulation. And inthe light of this problem, we researched and developed a new kind of impact needle,which could improve the work efficiency and the treatment effect by decreasing thelateral displacement and increasing impact speed.