Abstract: To prevent micro electrothermal actuators from becoming damaged under high overload conditions, this paper conducts research on the anti-high overload performance of U- and V-shaped micro electrothermal actuators. The structural parameters of U- and V-shaped micro electrothermal actuators with equivalent output performance were determined by evaluating different types of micro electrothermal actuators exhibiting the same output displacement at the highest temperature. Finite element simulations of the actuators were conducted to assess their performance under impacts in various directions, amplitudes, and pulse widths. The values of the actuators’ first principal stress were derived from the simulation results. The pulse width-amplitude curves were obtained when the first principal stress of the two types of actuators reached the allowable stress. These curves categorize the impact loads into safe loads and failure loads, thus enabling an evaluation of the resistance to high overloads of both actuators. The simulation results were validated through the execution of a series of machete hammer experiments. The finding of the research indicates that when subjected to loads with pulse width of 80μs-100μs, the U-shaped electrothermal actuators exhibited a fracture under an overload of 3781g-8036g. In contrast, the V-shaped electrothermal actuators have the capacity to withstand an overload of 18000g, which allows them to resist the impact of dropped ammunition on a solid surface. The findings of this research serve as a point of reference for the selection and design of micro electrothermal actuators in high overload environments.

Key words: micro electro-mechanical systems (MEMS), U-shaped electrothermal actuator, V-shaped electrothermal actuator, anti-high overload, finite element analysis