Study of ultrasonic vibration-assisted forming in copper cylinder compression

To investigate the effects of ultrasonic vibration on copper cylinder compression, the ultrasonic vibration-assisted forming system was developed and the ultrasonic vibration-assisted compression experiments were carried out on copper cylinders. Experiment results show that the ultrasonic vibration could cause the geometry effect and the softening effect. The end of the copper specimen shows different shapes with different ultrasonic powers. When the ultrasonic power reaches 1.8 kW, the specimen takes on an inverted drum shape. By measuring the forming force during the ultrasonic vibration -assisted compression, it is confirmed that the copper specimens are softened at different modes under different ultrasonic powers. To test the forming process, an ultrasonic vibration was superimposed on the specimen placed in the mold by a series of preloading forces. These results in combination with the stiffness characteristics of the forming system reveal that ultrasonic vibration can reduce the yield stress of copper.