THE USE OF HERMITIAN TIMOSHENKO FINITE ELEMENT FOR THE DYNAMIC ANALYSIS OF A LIGHTWEIGHT MANIPULATOR

Document Type : Original Article

Authors

School of Mechanical Engineering, Cranfield University, Cranfield, Bedford, MK43 OAL, UK.

Abstract

Literature studies have demonstrated that lightweight manipulators of highspeed should be designed with the effects of shear deformation and rotary inertia being taken into consideration, especially for short beams. It has been found that Lagrangian Timoshenko beam elements are overstaff for small thickness, and such elements cannot be accurately employed for thin beams. This phenomenon is referred to as shear locking. This parametric study demonstrates the advantages of using a Hermitian Timoshenko finite element for the dynamic analysis of a lightweight manipulator. The Lagrangian principle is used for the derivation of the governing differential equations for the beam element. A computer program is developed to solve the proposed model and to easily accommodate any future developMents. The accuracy of the proposed model has been verified through the comparison of the dynamic response with two published models, one of them is based on assumed mode method and the other one is based on an isoparametric finite element method.