Failure mechanism analysis of quartz accelerometer under vibration condition

Abstract

Accelerometer is a sensor which converts acceleration that acts on the transport input shaft to an electrical signal by a variety of means of measurements. Acceleration will change into velocity by integration, while acquire the position information by the second integration. Through measuring linear acceleration of vehicle along the certain direction by accelerometer, inertial navigation system can determine the instantaneous velocity and position of transporter relative to the reference coordinate system by necessary integration and coordinate transformation. As one of the most critical parts of platform inertial navigation system, accelerometer performance directly affects the measurement accuracy, stability of the system, and the ultimate navigation accuracy. Accelerometer is mainly affected by vibration stress during transport process. Vibration will make accelerometer's structure distort, resulting in drift of bias value and scale factor. The flexible bridge of accelerometer may break down because of the stress concentration in the instantaneous impact. Finite element analysis software ANSYS will be used for quartz accelerometer to model and simulate. Analysis of random vibration or shock vibration indicates that the quartz accelerometer can withstand the instantaneous impact for the provision of accelerometer magnitude of 180g. Meanwhile, single point response spectrum analysis under the transport vibration comes to a conclusion that accelerometer's structure will distort under the transport vibration, leading to the change of pendulum performance and torque coefficient, at last resulting in the parameter drift. The parameter drift is often caused by the releasing process of structure residual stress. The failure of accelerometer resulting from the parameter drift could be avoided by the method of stabilization of material and acceleration stabilization of the accelerometer.