采用有限元方法, 对强超声作用下金属板中裂纹面的动接触行为以及摩擦发热现象进行了三维热力耦合模拟。在有限元模型中, 利用压电-热弹类比方法模拟功率超声换能器激励, 而采用基于罚函数方法的接触-碰撞算法模拟裂纹面之间的动接触相互作用。通过有限元模拟, 定量计算了裂纹面上的摩擦发热现象, 对功率超声换能器激励下裂纹板的振动特性、裂纹面的动态接触过程以及裂纹处的温度分布进行了分析。有限元仿真结果可以合理解释在超声红外热像技术中观察到的现象。

When a plate containing a crack is excited by intensive ultrasonic pulses, a coupled three-dimensional thermo-mechanical FEM model is built to simulate the phenomenon of dynamical contact and frictional heating between both lateral faces of the crack. In the FEM model, the high-power ultrasonic transducer is modeled by using a piezoelectric thermal-analogy method, and the dynamical interaction between both faces of the crack is modeled using a contact-impact theory. The penalty method is used as contact-impact algorithm to simulate the contact behavior between both faces of the crack. During the FEM simulation, the frictional heating taking place at both faces of the crack is quantitatively calculated, and the vibration characteristics of the plate, the dynamical contact behavior of two surfaces of the crack and the temperature distribution around the crack zone were subsequently analyzed. The computational results could reasonably explain reasonably the phenomena observed in ultrasonic infrared imaging technique.