As the core component of energy transfer in weapon system, safety and arming (S&A) devices affect the safety, reliability, and damage ability of the weapon. Micro-electromechanical systems (MEMS) S&A devices have been widely investigated for their smaller structure size, higher functional integration, and better smart functionality. This paper proposes the design of a multi-physics field-driven MEMS S&A device. The S&A mechanism is composed of a setback mechanism, a spin mechanism, and an electrothermal mechanism, achieving multiphysics-arming. With the coordination of the three mechanisms, the S&A device can produce a 1 mm displacement. The displacement generated allows the S&A device to switch between safety status and arming status. The unlock conditions and overload resistance of each mechanism are obtained by finite element simulation. Based on SOI wafers and silicon oxide wafers, the chips were fabricated and packaged. Several tests were carried out to verify the working condition and overload resistance of the S&A device. The result shows that under a voltage of 11 V and a rotation speed of 8000 r/min, with a size no more than 10 mm $\times$ 10 mm $\times$ 1.5 mm, the device works smoothly and can withstand an overload of 25,000 g.

In response to issues such as the unclear characteristics of isolation mechanisms, explosion-proof ability, high dynamic environmental response characteristics in MEMS safety systems, and insufficient design verification basis, the basic theory of the motion process of the explosion-proof mechanism was analyzed starting from the working principle of the explosion-proof mechanism. The explosion-proof performance and response characteristics of the explosion-proof mechanism under different preset conditions were studied through simulation calculation and experimental verification. The results show that when the thickness of the nickel material partition is less than 0.3 mm, it can block the high-speed impact of titanium flying plates with a design size of Φ 0.75 mm ×0.025 mm and the speed not exceeding 2,800 m/s; when the projectile speed is not less than 20,000 r/min, the isolation mechanism can move in place normally and lock successfully, while also having the ability to resist high overload impact. Under the action of not more than 50,000 g rear seat overload, the structure of the explosion-proof mechanism is intact without any failure.

The electrothermal actuator designed in this article is used to play a delayed release role in the security mechanism of MEMS security systems, which requires periodic control signals to drive the centrifugal slider and other components of the security device through electric thermal force multi physics coupling in a complex mechanical working environment, enabling them to unlock and achieve reliable release of the security function. This article adopts the lumped parameter design method to establish a mathematical model of the electrothermal micro-actuator, and conducts theoretical analysis. Through finite element analysis and calculation, an electric thermal force coupling model of the micro actuator is established, and electrothermal energy conversion effect and the effects of V-beam parameters on the deformation and displacement of electrothermal micro-actuator are studied.