静加圧力を考慮した超音波プラスチック溶接の動的接触解析

抄録

Ultrasonic plastic welding is widely used for joining thermoplastic parts. This joining technique uses frictional heat and deformation heat at the contact interface of the parts, being generated by high frequency mechanical vibration. In this paper, we propose a method for predicting the dynamic behavior of the contact interface by the dynamic contact analysis of finite element method. Especially it reproduces the welding pressure in the welding process. In the contact analysis, an upward force is applied to the fixture to reproduce the welding pressure and a sinusoidal displacement with the driving frequency is applied to the horn. Furthermore, we investigate the effect of driving frequency on the dynamic behavior of the interface when the horn is driven at each of two different frequencies: 15kHz or 19kHz. The results show that considering the welding pressure in the contact analysis leads to the predicted dynamic behavior of the parts in good agreement with the experimental data. The relative displacement between the upper and lower parts and the elastic strain at the contact interface for the 15kHz driving frequency are larger than those for the 19kHz, additionally the elastic strain for the 15kHz is widely distributed.