Nameric Simulation On Acoustic Propagating During Ultrasonic Liquid Joining Of Aluminum Matrix Composites

Ultrasonic welding is one of usually used joining methods of Al-based metal matrix composites. However, the time of the ultrasonic welding is too short to be observed. Hence, a numerical simulation of ultrasonic welding embodies great values on the investigation of the ultrasonic welding process.In order to analyze the mechanism for the acoustic wave transfer inside the Al metal matrix composites and liquid Zn-Al filler droplet, the associated wave equations are set up and numerical simulation is carried out with ANSYS FEM software.Results show that: as the amplitude of ultrasonic vibration increases, the displacement of the same time and location also increases ; when the amplitude of ultrasonic changes, the rule of the distribution of displacement filed keeps down, that is, the comparative value of displacement of different areas and the location of the most displacement are the same; The largest displacement, which is larger than the amplitude of the load, always occurs at the left and middle parts of the specimen; point units on the surface of the specimen keep vibrating with the same frequency as the load.When acoustic wave spread from the Al-based metal matrix composites into the liquid Zn-Al filler drop, negative pressure will come into being inside the liquid filler drop. The area which goes to engender negative pressure will give rise to the force to form air bubble. When the air bubble is broken, the cavitation effect will come into being because of the powerful shock wave caused by collision inside the liquid. As amplitude of ultrasonic vibration increases, the negative pressure inside the liquid filler drop also increases, which will result in the more obvious cavitation effects. As the distance between the liquid drop and load increases, the value of negative pressure changes, which results in the change of the cavitation effects.The vibration on the specimen surface of the Al-based metal matrix composite is determined by a laser doppler vibrometer (Polytec OFV-502).The testing results are consistent well with those obtained from simulation. The observation of wetting phenomena of Zn-Al droplet on Al-based metal matrix composites...