Research Of Ultrasonic Vibration Assisted Aluminum Alloy Bending

Ultrasonic vibration aided plastic forming technology can not only improve forming limit, reduce forming force, but also improve quality of formed parts, and make it possible to process high hardness and brittleness materials which is difficult to process. At the same time, in drawing, deep-drawing, blanking, upsetting, stamping, and such plastic forming process, it has been widely used. But so far, study on ultrasonic vibration assisted bending is very limited. Ultrasonic vibration has a great advantage and development prospect for the light alloys, such as aluminum alloy in improve bending formability, reducing bending springback, and improving the quality of bending parts.Ultrasonic vibration bending of 6061 aluminum alloy is studied in this paper. By combining experiments and numerical simulation, the influence on the plastic deformation process is also revealed. The main tasks are as follows:Based on the research status of ultrasonic vibration aided plastic forming technology, this paper studied the ultrasonic vibration plastic forming system components and basic working principle. Start with volume effects and surface effects, research results and theoretical models was summarized, which provided theory foundation for studying influence mechanism of ultrasonic vibration on bending.Firstly, ultrasonic vibration aided tensile test device was designed, and a series of ultrasonic vibration assisted tensile tests were carried out which using ultrasonic vibration in the form of a peak vibration displacement of 4μm and 6μm at the frequency of 20kHz. Moreover, load-displacement curves during tensile deformation were obtained. Ultrasonic vibration aided numerical modeling method of finite element simulation of bending was studied, and numerical simulation of ultrasonic vibration aided bending process was revealed as well.The influence of ultrasonic vibration on distribution and vibration of stress and strain, stress-strain curves and springback was studied by numerical simulation of ultrasonic vibration aided bending of 6061 aluminum. Moreover stress superposition and ultrasonic hardening mechanism were explained. By bending test of 6061 aluminum aided by ultrasonic vibration, which is in the form of a peak vibration displacement of 3.34μm,3.96μm,4.48μm,4.96μm at the frequency of 15kHz, the influence of ultrasonic vibration parameters and clearance between punch and die on springback and surface quality of 6061 aluminum plate bending were studied, and as a result, the mechanism of the surface effect and volume effect were explained. At the same time, the effects of ultrasonic vibration on the grain size and microhardness of the deformation zone were studied, and the effects of ultrasonic vibration on the material microstructure were revealed consequently.