Dynamic analytic model of mechanism with links fabricated from symmetric laminates

Abstract

A four-bar linkage mechanism with links fabricated from symmetric laminates was studied. The mass matrix of the beam element was obtained in light of the mass distribution characteristics of composite materials. The stiffness matrix of the beam element was derived from the constitutive equations of each layer and the relationship between the strain distribution and the node displacement of the beam element. The specific damping capacity of the beam element was analyzed according to the strain distribution of the beam element and the strain energy dissipation caused by vibration in each direction of each layer; and the damping coefficients were obtained according to the principle that the total energy dissipation of the beam element was equal to the work done by the equivalent damping force during a cycle of vibration, from which the damping matrix of the dynamic equations was obtained. Using the finite element method, the dynamic analytic model of the mechanism was obtained. The dynamic responses and natural frequency of the mechanism were obtained by simulation, respectively, and those of the simulation obtained by the proposed model were analyzed and compared with the results obtained by the conventional model. The work provides theoretical basis to a certain extent for the further research on nonlinear vibration characteristics and optimum design of this kind of mechanism.

Keywords

linkage mechanism / finite element method / composite materials / damping / dynamic analysis