Study on residual surface stress during ultrasonic vibration machining of aluminum alloy finite element method

Focusing on the surface quality issues of aeronautical aluminum alloy structural parts, a two-dimensional orthogonal thermo-mechanical coupling model of 7075-T651 aluminum alloy using the Johnson-Cook constitutive model was developed with finite element software ABAQUS. Under the same cutting parameters, the surface layer residual stresses were compared between conventional cutting (CC), vibration cutting along the cutting direction (CVC) and vibration cutting in the axial direction (AVC), and the effects of ultrasonic vibration cutting parameters, vibrational frequency and vibrational amplitude on the residual stresses were studied. The validity of the simulation model was verified by quoting experimental data of residual stress in relevant literatures. The results indicate that residual surface stress of the three cutting approaches shows compressive stress, which tends to the depth-direction residual tensile stress. Vibration cutting is capable of significantly enhancing residual compressive stresses on the workpiece surface. Residual compressive stress on the surface decline with a rise in cutting depth and speed. With the growth in vibration amplitude or frequency, surface residual compressive stresses increase gradually.