Materials selection of flexure accelerometer using Ashby chart

The characteristic and structural parameters of flexure hinges, which are very important components in the flexure accelerometer, explicitly affect the performance of the flexure accelerometer. The analytical equations of maximum stress, rotation angle and rotation stiffness along the sensitive axis of leaf flexure hinges are deduced. And based on the failure conditions, the calculating formula of the maximum rotation angle of the flexure hinge before failure is derived. As the geometric parameters are same, the maximum rotation angle is related to the ratio of the strength and the elastic modulus of the material. Then the materials selection principle is according to failure resisting force indexes of components, and failure modes under the condition of working loads and overload are analyzed. Based on the method of Ashby charts, charts of strength and elastic modulus of common engineering materials are drawn. Materials indexes of the design example are derived based on stress, stiffness and design requirements of the flexure hinge. The curves corresponding to materials indexes are plotted in the Ashby chart and the appropriate materials manufacturing flexure hinges are chosen according to the position of the curve.