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  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2025, Vol. 61 ›› Issue (2): 86-96.doi: 10.3901/JME.2025.02.086

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Multiphysics Coupling Simulation and Analysis of Ultrasonic Welding Considering Variable Friction and Acoustic Softening Effects

HU Weifei1,2,3, DENG Xiaoyu1,3, ZHANG Tongzhou1,3, LIU Zhenyu1,2,3, TAN Jianrong1,2,3   

  1. 1. State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027;
    2. Engineering Research Center for Design Engineering and Digital Twin of Zhejiang Province, Hangzhou 310027;
    3. School of Mechanical Engineering, Zhejiang University, Hangzhou 310027
  • Received:2024-02-21 Revised:2024-08-15 Published:2025-02-26

Abstract: As a solid-state bonding technology, ultrasonic welding is often used in the packaging process of power semiconductors. It is difficult to investigate the complex transient process and bonding mechanism of ultrasonic welding only by experimental observation. To explore this complex dynamic process, A three-dimensional finite element model of “acoustic-thermal-mechanical” multi-physics coupling is established. The bidirectional coupling of heat and friction is considered, and the softening effect of ultrasonic on the material is introduced on the basis of thermal softening. The acoustic softening coefficient is dynamically updated by the amplitudes of the two workpieces obtained from the simulation outputs, which improves the accuracy of the finite element simulation model. Based on the simulation model, the complex mechanical behavior of the workpieces is further investigated, including amplitude transfer, temperature distribution and plastic deformation. The influence of process parameters, namely amplitude and pressure, on the welding process is also analyzed. The result shows that the simulated results of temperature and plastic deformation of the workpieces are consistent with the experimental data. The ultrasonic vibration energy decays when the vibration is transferring between the workpieces. The temperature at the center of the welding area is significantly higher than that at the edge, but is still far lower than the melting point of the material. Both thermal and acoustic softening have significant effects on the plastic deformation of the workpieces, and the contribution ratio of acoustic softening to the deformation is about 38%. In addition, ultrasonic welding process parameters have great influence on the welding process, which has potential meaning for improving welding quality.

Key words: ultrasonic welding, multi-physics coupling, amplitude transfer, temperature distribution, plastic deformation

CLC Number: