Experimental and numerical analysis of deformation and residual stress produced by stressing ultrasonic impact forming (SUIF)

Ultrasonic impact forming (UIF) is an essential cold working process for forming large thin-walled components. Stressing ultrasonic impact forming (SUIF) can produce more deformation than UIF in the prebending direction. In this paper, a four-step numerical model including prestress submodel, impact treatment submodel, data transfer submodel and prestress forming submodel is developed to simulate the SUIF process. The effect of nonuniform residual stress on plate deformation is investigated, the change regulation of residual stress is discussed, the effect of elastic prebending radius on the plate deformation is analyzed. The narrow plate can obtain a nearly single curvature deformation by SUIF. Compared to narrow plate, the square plate can produce smaller deformation in device offset direction. Compared to UIF, SUIF can produce smaller compressive stress in the top surface layer, larger tensile stresses in device moving direction, and smaller tensile stresses in device offset direction; SUIF can produce larger deformation in device offset direction. With the decrease in prebending radius, compressive residual stresses changes little, and the tensile stress increases in the device offset direction, the deformation increases in the device offset direction and decreases in the device moving direction.