Based On MEMS Device Long/short Pulse Width Shock Equivalent Test Method Research

The pulse width of shock overload in extremely high overload environments can often reach more than ten milliseconds.Laboratory overload test methods such as Hopkinson rod and air cannon can only simulate shock environments of a hundred microseconds to milliseconds,which is far from the high overload long-duration environments of more than ten milliseconds.In this thesis,we propose an equivalent test model for short pulse-width high peak shocks of Hopkinson rod within 100 microseconds and extended pulse-width low peak shocks of more than ten milliseconds in extreme environments for MEMS devices with an excellent dynamic performance in shock environments;and verify the validity of the equivalent shock model through dynamic mechanical simulation of accelerometers and shock tests of Hopkinson rod.The general idea is as follows:First,based on the impact dynamics model of the cantilever beam structure and the changes in the energy transfer process,an equivalent impact analysis method based on the "effective impact energy sum" has been proposed to obtain the identical impact model with long pulse width and low peak value and short pulse width and high peak value.Secondly,the equivalent impact model has been applied to the MEMS device.The ABAQUS finite element simulation software has analyzed the acceleration sensor’s dynamic response and calculated the device’s "effective impact energy sum" for different shocks under the equivalent impact model.Finally,the emotional mechanical response of the accelerometer under other shock signals has been obtained by Hopkinson rod dynamic test device;the test results and simulation results are matched well,and the relative error was less than 10%,verifying the feasibility of the equivalent incidence model proposed in this thesis.The study of the long/short pulse width impact equivalence method can predict the dynamic response of the device under extremely harsh environments,improve the reliability of the device and the success rate of the test,break through the limitations of overload pulse width mismatch between live fire and Hopkinson rod test methods and the difficulty of equivalence assessment,and provide theoretical and technical support for the formation of an equivalence method for high overload mechanical test environments.