Simulation of planar flexible multibody systems with clearance and lubricated revolute joints

Abstract

Modeling of clearance joints plays an important role in the analysis and design of multibody mechanical systems. Based on the absolute nodal coordinate formulation (ANCF), a new computational methodology for modeling and analysis of planar flexible multibody systems with clearance and lubricated revolute joints is presented. A planar absolute nodal coordinate formulation based on the lockingfree shear deformable beam element is implemented to discretize the flexible bodies. A continuous contactimpact model is used to evaluate the contact force, in which energy dissipation in the form of hysteresis damping is considered. A force transition model from hydrodynamic lubrication forces to dry contact forces is introduced to ensure continuity in the joint reaction force. A comprehensive study with different lubrication force models has also been carried out. The generalized-α method is used to solve the equations of motion and several efficient methods are incorporated in the proposed model. Finally, the methodology is validated by two numerical examples.

On the continuous contact force models for soft materials in multibody dynamics

“…This fact is not surprising because, for instance, Lankarani and Nikravesh [33] derived their model for high values of restitution coefficient, being, therefore, valid for hard contacts, such as those between metals [49][50][51][52]. The values of the coefficient of restitution for soft materials are low or medium [40,43,48,53], which clearly indicate that the hysteresis damping factor given by (6) and (8) cannot be used.…”

A Comparative Study of Joint Clearance Effects on Dynamic Behavior of Planar Multibody Mechanical Systems

“…where is angular velocity of link and is the angular acceleration of link. denotes the number of the moving links ( 1,2,3,4,5) and designates the number of the angular position (Tian et al, 2010). We can get the values of angular velocity and angular acceleration for linkages in the following equations:…”

Mathematical Model of the Heald with Damping Element

“…In view of the fact that the transforming section of the shedding motion is a joint mechanism, a number of procedures and methods can be employed for modelling of the above structure [5][6][7][8][9][10]. It is possible to apply successfully the description of a mechanism based upon the method of devising motion equations by means of Lagrangian equations of the second type according to [10].…”