Analysis Of Reliability Of The Slanted Micro-cantilever Subjected To The Shock And Vibration Environment

Now with the rapid development of MEMS, the reliability has already become to one of the key issue for its application and industrialization. We know vibration and shock is a typical service environment, Such as various vibration, impact and shock during transport and service, especially in the military and aerospace industry, taking more requirements to withstand strong loads. MEMS under vibrating and shock load may fail in several different modes including fracture, stiction, delamination, wear and so on. Of a cantilever which is the fundamental element of MEMS and is widely used in microstructures such as micro machined gyroscope, micro accelerometer, micro sensor, and so on.In the paper the MEMS reliability in vibration and shock environment is studied by theory analysis, ANSYS simulation, and experiment by taking the example of the slanted micro cantilever, which is used in a novel micro-machined gyroscope. The main research content in the following aspects:1. As the first step we analysis the bending spindle azimuth, spindle of inertia and bending stiffness of the unsymmetrical cross-section, then analyzed in the work process of the micro force and damping. Static analysis of the slanted micro cantilever by both of theoretical and ANSYS simulation validate the feasibility and accuracy of the application of ANSYS simulation of MEMS.2. Assuming the micro cantilever-mass system is simplified to a cantilever attached centralized quality in the end. We calculate the intermittent vibration displacement response. By the ANSYS simulation result of using the modal and harmonic analysis function show that when the shock frequency is under the cantilever nature frequency, the stress level and vibration amplitude can achieve reliability requirement, however nearly inherent frequency range, both rising sharply, its displacement excessive may lead to occurrence of black and substrate adhesion failure or broken by a collision with the wall.3. Based on quasi-static theory this paper studies on the dynamic response characteristic of the slanted micro cantilever under the shock by vibration theory. The result shows that when the shock load and the beam is equal to the natural frequency , the maximal displacement and stresses of slanted cantilever occurred in the force vibration stage, the impact of the value of about static load on the end of the beam of 1.707 times. Finite element simulation results validate the conclusion. We can get a conclusion that the main failure mode of slanted micro cantilever in the shock is adhesives failure, and it is strong in the strength reliability.4. In order to validate the theoretical analysis and ANSYS simulation, based on exiting condition, we design a samples shock test. Furthermore the correction of theory analysis and ANSYS simulation is been validated by the experimental results.To sum up, this dissertation got a clear understanding of the dynamic response characteristic of the slanted micro cantilever under the shock .The results can be used for guiding the failure modes analysis of MEMS, and provided the rules for MEMS reliability design.