Accurate prediction of the friction-mediated interaction between workpieces in ultrasonic welding requires nonlinear multi-physical models. Local contact points that are in slip receive a heat flux from friction, which raises the local temperature and therefore, changes the local material stiffness and local stresses. These local changes affect the contact status and the overall dynamics. The effects of vibration amplitude and clamping force on the nonlinear friction behavior in ultrasonic welding of aluminum alloy to carbon fiber reinforced thermoplastic (CFRTP) are particularly important process parameters that can be controlled. Their effect is investigated through a multiphysics coupled model with consideration of the nonlinear contact, nonlinear structural dynamics, and the transient heat conduction. Solutions are obtained by combining the harmonic balance method with the finite element method. Intuitively, large amplitudes promote sliding and higher heating, while large clamping forces can promote sticking and lower heating. Unexpectedly however, results show that the amplitude has a limited influence on the process, while the clamping force has a significant influence. That is because optimal heating results from a balanced manifestation of sticking, sliding and temperature at the interface. In particular, results suggest that a low clamping force with a high vibration amplitude is desirable for the ultrasonic welding of aluminum alloys to CFRTP composites.

超声焊接中工件之间的摩擦介导相互作用的准确预测需要非线性多物理模型。滑动中的局部接触点会从摩擦中获得热通量，这会升高局部温度，因此会改变局部材料的刚度和局部应力。这些局部变化会影响联系状态和整体动态。铝合金与碳纤维增强热塑性塑料（CFRTP）进行超声波焊接时，振动幅度和夹持力对非线性摩擦行为的影响是可以控制的特别重要的工艺参数。通过考虑非线性接触，非线性结构动力学和瞬态热传导的多物理场耦合模型，研究了它们的作用。通过将谐波平衡法与有限元法相结合来获得解。直观地讲，大振幅会促进滑动和更高的热量，而大的夹紧力会促进粘结并降低热量。但是，出乎意料的是，结果表明，振幅对过程的影响有限，而夹紧力的影响却很大。那是因为最佳的加热是由于界面处的粘着，滑动和温度的平衡表现而产生的。尤其是，结果表明，将铝合金超声焊接到CFRTP复合材料时，需要具有高振动幅度的低夹持力。但是，出乎意料的是，结果表明，振幅对过程的影响有限，而夹紧力的影响却很大。那是因为最佳的加热是由于界面处的粘着，滑动和温度的平衡表现而产生的。尤其是，结果表明，将铝合金超声焊接到CFRTP复合材料时，需要具有高振动幅度的低夹持力。但是，出乎意料的是，结果表明，振幅对过程的影响有限，而夹紧力的影响却很大。那是因为最佳的加热是由于界面处的粘着，滑动和温度的平衡表现而产生的。尤其是，结果表明，将铝合金超声焊接到CFRTP复合材料时，需要具有高振动幅度的低夹持力。