High-power ultrasonic waves can transmit energy wirelessly through metallic enclosures, offering a promising solution for powering electromagnetically shielded electronics. However, sustained high-power operation induces self-heating, which alters material properties and creates a feedback loop that detunes the system and degrades performance. This work presents a validated multiphysics finite element model that captures the coupled acoustic, thermal, mechanical, and piezoelectric interactions driving these effects. The model integrates frequency-domain simulations for ultrasonic dynamics coupled with time-dependent modeling for thermal evolution, and static analysis for thermomechanical stress, enabling prediction of nonlinear behavior under realistic conditions. Temperature-dependent material nonlinearities (20–100 °C), including experimentally characterized piezoelectric properties, were incorporated into the model. Model accuracy was assessed using a 1-MHz ultrasonic setup capable of transmitting up to 100 W through a stainless-steel wall. Real-time measurements of temperature, electrical impedance, and power transfer were collected across operating frequencies. The model reproduces key experimental trends, including resonance detuning, thermal runaway onset, and safe operating limits. This modeling framework enables predictive design and optimization of high-power ultrasonic systems by identifying critical constraints, failure mechanisms, and strategies for thermal management, material selection, and frequency control.
Zakaria et al. (Wed,) studied this question.