BUCKLING ANALYSIS OF A 2-DOF PARALLELMECHANISM COMPOSED OF RIGHT-ANGLE-NOTCHFLEXURE UNIVERSAL HINGES

摘要

With respect to the great ratio of the length to the thickness ofrnright-angle-notch flexure hinge, the necessity of the study onrnthe buckling characteristics of the right-angle-notch flexurernuniversal hinges and the compliant parallel mechanismrncomposed of them, was presented. The mathematical model,rnfor calculating the buckling critical force of the right-angle-notchrnflexure universal hinge, was established on thernapproximate differential equation of deflection curve of thernmaterial bending theory. With this, the conception ofrnequivalent section inertial moment was put forward. Finally,rnbased on the former theoretical research on the compliantrnparallel multi-bar mechanism composed of the right-angle-notchrnflexure hinges, the mathematical formula forrncalculating the buckling critical force of the compliantrnparallel mechanism was proposed. The buckling critical forcernof the sample has been measured by experiment and by FEArn(Finite Element Analysis) with the commercial softwarernANSYS 8.0. The values from the mathematical model, fromrnexperiment and from FEA separately all met well, whichrnindicated the correctness of the mathematical model. Inrnsummary, the mathematical model proposed above can bernused in the optimization of the design of the right-angle-notchrnflexure hinge and it's compliant parallel mechanism inrnbuckling characteristic.