Design And Analysis Of MEMS Actuator In Fuse

MEMS actuator is a kind of transducer components, in other words the energy can be transformed into mechanical energy, which has the advantages of light quality, small volume, simple structure and suitable for application in the fuze.This paper introduces a kind of out-of-plane micro electro thermal actuator, which is used in security insurance system of the fuze and based on the principle of bimetal film thermal expansion, has the ability of low drive voltage, large drive displacement and resistance to overload. Using polymer SU-8 and Nickel material as the body material of the actuator. Through heating resistance wire by electricity, the actuator produces out-of-plane motion in perpendicular axial direction of the device and the bias layer contact with the substrate, completing signal output. This paper emphatically introduces the basic principle of bimetal film, and analyzed the work environment of the actuator, such as electric field, damping field and acceleration field. It is concluded that the acceleration and driving voltage has corresponding relationship, simulating the process of the model and analyzing size effect on the performance in theory, determining the main factors influencing the performance of the actuator, the length is 780μm, the thickness of SU-8 layer is 10μm and Nickel layer is 5μm.Using Coventor Ware software to establish the three-dimensional model, the geometric structure is optimized and electrothemal capabilities are determined theoretically. Giving the analysis of electrothermal, heat conduction, heat convection, damping analysis, modal analysis, overload resistance analysis and mechanical-electrical and thermal coupling analysis, finally checking stress of actuator under different fields respectively, verification actuator satisfies the requirement of strength.Through analysis, the actuator’s displacement is 18μm and temperature rises from 293 K to 440 K under the voltage of 0.5V within 2ms; it is able to resistance 10000 g acceleration shocking; in coupled field analysis, finding out several groups of driving voltage and acceleration corresponding relation, concluding that the practical work of drive voltage within 0.4V. The combination of acceleration and thermal stress on the actuator shorten the response time and convenient for application in fuze, realized low voltage, large displacement and high overload. Finally checking the maximum stress of the actuator is smaller than the allowable stress of Nickel. The result shows that the electro-thermal actuator has a high reliability.