Author(s): HU Jun-feng, ZHENG Chang-hu, XU Gui-yang, School of Mechanical & Electrical Engineering, Jiangxi University of Science and Technology
Pages: 81-86
Year: 2016 Issue:  1
Journal: Journal of Machine Design
Keyword:  bridge mechanism; fintite element method; dynamic performance; compliant mechanism;
Abstract: In order to describe dynamic performance of a bridge compliant mechanism accurately, the finite element method was applied to build a dynamic model, and the dynamic performance analysis was carried out according to the proposed model. Euler-Bernoulli beam was adopted to simulate the mechanical behavior of the flexure hinge and links. The stiffness matrix of the bridge mechanism was obstained using the principle of minimum potential energy. The mass matrix and dynamic equations were built using Lagrange equation. The sensitivity analysis of natural frequency with respect to size parameters of the flexure hinge, dynamic stiffness and dynamic stress analysis were carried out based on the finite element model of the bridge mechanism. The analystical results showed that the higher ratio between the thickness and length of the flexure hinge can improve response speed. The larger vibration occurred in the motion direction of the mechanism, and the larger overshoot might occurred while closing to the natural frequency. The dynamic stress exerted on the flexure hinge near the driving ends was larger, thus fatigue fracture might easy to take place.