Finite element simulation and experimental investigation of machining induced residual stresses in ultrasonic elliptical vibration-assisted turning

In this study, an experimental study and three-dimensional finite element simulation of ultrasonic elliptical vibration-assisted turning (UEAT) are investigated. In addition, the comparison of this process with ultrasonic-assisted turning (UAT) and conventional turning (CT) is also provided. First, a three-dimensional FEM has been developed to study the cutting forces, friction coefficient, and residual stresses in CT, UAT, and UEAT. For the experimental tests, a special design of elliptical vibration tool with two bending modes (along feed and cutting speed) is proposed and fabricated. Then, the effect of vibration amplitude, cutting speed, and feed on the machining residual stresses during hard turning of AISI4340 steel has been explored. Finally, the developed FEM is validated with the experimental test results. According to the obtained results, by applying elliptical vibrations on the cutting tool in UEAT, machining residual stresses became more compressive on averagely by 49%. Moreover, the application of elliptical ultrasonic vibrations with amplitudes of 6 and 12 μm had made machining residual stresses 34 and 64% more compressive, respectively.