Micromachined accelerometer is a kind of inertial MEMS devices, which usually operate under intensive impact loading. The reliability of micromachined accelerometers is one of the most important performance indices for their design, manufacture and commercial application. Therefore, great concern has been aroused for the overload reliability of such devices. In the present paper, drop tests and some structural failure analyses have been implemented for a kind of newly designed microaccelerometer fabricated by the standard bulk-machining process of single crystal silicon, and numerical simulation of structural failure behaviour has been carried out for the new device subjected to impulsive loading. [ABSTRACT FROM AUTHOR]