【摘要】 利用倾斜支撑微梁结构大挠度后屈曲的非线性横向刚度,设计了一种新型屈曲式微机械加速度开关.该开关采用倾斜微梁支撑敏感质量块,两折叠梁固定于质量块的上下表面,保证开关动作的方向性.当外界加速度达到设定的阈值时,梁发生屈曲使开关迅速闭合,加速度低于截至门限值时,屈曲微梁弹性力使开关断开.开关设计中分析了气膜阻尼力和触点接触力对系统性能的影响,建立了多力耦合作用下加速度开关系统的动力学模型,并运用数值方法对含有椭圆积分的强非线性系统进行动态仿真分析,开关响应时间低于6ms.实验表明开关具有良好的阈值特性和接触可靠性,充分证实了屈曲梁结构应用于惯性微感应器件设计的可行性.更多还原

【Abstract】 In this paper, a novel MEMS acceleration switch is designed by utilizing the nonlinear transversal stiffness of a post-buckling oblique micro-beam with both ends fixed. This device consists of two oblique micro-beams with an inertial mass in the middle. The other two folding beams are designed to ensure the inertial mass to move in one direction. When the outside acceleration reaches a threshold value, the beams buckle and the switch closes soon; when the inertial force is less than a certain value, the switch opens quickly under the effect of the elastic force developed by the post-buckling beams. In the dynamic design process, considering the nonlinear transverse force of the post-buckling beam, the damping force is calculated using the Reynolds Equations, and the tip-to-drain contact is modeled by elastic Hertz theory. The good threshold characteristic, perfect anti-jamming performance and high contact reliability of the switch are showed after the numerical simulation. The response time is less than 6 ms when the switch is triggered by a threshold acceleration a_c=25g, and the switch cut off quickly when the cut-off acceleration is under a_d=5g.更多还原