Dynamic analysis of planar mechanical systems with clearance joints using a new nonlinear contact force model

2016 ◽  
Vol 30 (4) ◽  
pp. 1537-1545 ◽  
Author(s):  
Xupeng Wang ◽  
Geng Liu ◽  
Shangjun Ma
2013 ◽  
Vol 29 (4) ◽  
pp. 653-660 ◽  
Author(s):  
Z. F. Bai ◽  
Y. Zhao ◽  
X. G. Wang

ABSTRACTClearances in the joints of mechanism cause vibrations and noise in mechanical systems. The contact force model is the important factor in dynamic analysis of mechanical systems with clearance. This paper presents a nonlinear contact force model for revolute joint with clearance, which is a hybrid model of the Lankarani-Nikravesh model and the improved elastic foundation model. The framework of the Lankarani-Nikravesh model is used with the nonlinear stiffness coefficient derived using the improved elastic foundation model and the damping applied in introducing the ratio of the nonlinear stiffness coefficient of the improved elastic foundation model and contact stiffness of Lankarani-Nikravesh model. Finally, the nonlinear hybrid contact force model is analyzed and discussed. The hybrid contact force model presented in this paper is a nonlinear continuous contact force model, which extends contact modeling of joints with clearance and has a greater applicable scope.


Author(s):  
P. Flores ◽  
J. Ambro´sio ◽  
J. C. P. Claro ◽  
H. M. Lankarani

This work deals with a methodology to assess the influence of the spherical clearance joints in spatial multibody systems. The methodology is based on the Cartesian coordinates, being the dynamics of the joint elements modeled as impacting bodies and controlled by contact forces. The impacts and contacts are described by a continuous contact force model that accounts for geometric and mechanical characteristics of the contacting surfaces. The contact force is evaluated as function of the elastic pseudo-penetration between the impacting bodies, coupled with a nonlinear viscous-elastic factor representing the energy dissipation during the impact process. A spatial four bar mechanism is used as an illustrative example and some numerical results are presented, being the efficiency of the developed methodology discussed in the process of their presentation. The results obtained show that the inclusion of clearance joints in the modelization of spatial multibody systems significantly influences the prediction of components’ position and drastically increases the peaks in acceleration and reaction moments at the joints. Moreover, the system’s response clearly tends to be nonperiodic when a clearance joint is included in the simulation.


Author(s):  
Sony Cheriyan ◽  
Paulo Flores ◽  
Hamid M. Lankarani

The main objective of this work is to present a computational and experimental study on the contact forces developed in revolute clearance joints. For this purpose, a well-known slider-crank mechanism with a revolute clearance joint between the connecting rod and slider is utilized. The intra-joint contact forces that generated at this clearance joints are computed by considered several different elastic and dissipative approaches, namely those based on the Hertz contact theory and the ESDU tribology-based for cylindrical contacts, along with a hysteresis-type dissipative damping. The normal contact force is augmented with the dry Coulomb’s friction force. An experimental apparatus is use to obtained some experimental data in order to verify and validate the computational models. From the outcomes reported in this paper, it is concluded that the selection of the appropriate contact force model with proper dissipative damping plays a significant role in the dynamic response of mechanical systems involving contact events at low or moderate impact velocities.


2020 ◽  
Vol 34 (7) ◽  
pp. 2701-2713
Author(s):  
Qi Wan ◽  
Geng Liu ◽  
Chunyu Song ◽  
Yong Zhou ◽  
Shangjun Ma ◽  
...  

2021 ◽  
Author(s):  
Bo Li ◽  
Min San Wang ◽  
Charis J Gantes ◽  
Xuan U Tan

Abstract The main goal of this work is to develop a comprehensive methodology for predicting wear in planar mechanical systems with multiple clearance joints and investigating the interaction between the joint clearance, driving condition and wear. In the process, an effective contact surface discretization method together with Lagrangian method are used to establish the dynamic equation of the multibody system. Considering the change of the contact surface, an improved nonlinear contact-force model suitable for the complicated contact conditions is utilized to evaluate the intrajoint forces, and the friction effects between the inter-connecting bodies are discussed using LuGre model. Next, the contact forces developed are integrated into the Archard model to compute the wear depth caused by the relative sliding and the geometry of the bearing is updated. Then, a crank slider mechanism with multiple clearance joints is employed to perform numerical simulations in order to demonstrate the efficiency of the dynamic procedures adopted throughout this work. The correctness of the proposed method is verified by comparing with other literature and simulation results. This study is helpful for predicting joint wear of mechanical systems with clearance and optimize the mechanism’s design.


Author(s):  
Qi Wan ◽  
Geng Liu ◽  
Chunyu Song ◽  
Shangjun Ma ◽  
Ruiting Tong

In order to meet the characteristics including small clearance, heavy load and large contact area of joints existed in rudder transmission system, a new normal contact force model is established, which is suitable for the large-area contact process and considers the coefficient of nonlinear variable stiffness as well as the axial length of bearing. The applicability of this model is verified by simulations under some conditions with different clearance size, restitution coefficient, initial collision speed and bearing's axial length. Furthermore, through the user-defined subroutine interface in ADAMS software, this modified contact force model is compiled and linked into the dynamic model of the rudder transmission system. The simulation results show that the dynamic response of the system with multiple clearance joints is not a simple superposition of that with one single clearance, and the dynamic interaction between these joints intensifies the oscillation and nonlinear characteristics of the system. This study provides a theoretical reference for the structural optimization and control strategy design of aircraft with clearance joints.


Sign in / Sign up

Export Citation Format

Share Document