Computational and Experimental Analysis of Mechanical Systems With Revolute Clearance Joints

2013 ◽  
Author(s):  
Sony Cheriyan ◽  
Paulo Flores ◽  
Hamid M. Lankarani
Keyword(s):  
Contact Force ◽  
Computational Models ◽  
Mechanical Systems ◽  
Contact Forces ◽  
Force Model ◽  
Connecting Rod ◽  
Normal Contact ◽  
Clearance Joints ◽  
Coulomb’S Friction ◽  
Experimental Apparatus

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.

scholarly journals Dynamic Response of Multibody Systems with Multiple Clearance Joints

2012 ◽  
Vol 7 (3) ◽  
Author(s):  
Paulo Flores ◽  
Hamid M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Equations Of Motion ◽  
Physical And Mechanical Properties ◽  
Contact Forces ◽  
Force Model ◽  
Normal Contact ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Dissipative Term

A general methodology for the dynamic modeling and analysis of planar multibody systems with multiple clearance joints is presented. The inter-connecting bodies that constitute a real physical mechanical joint are modeled as colliding components, whose dynamic behavior is influenced by the geometric, physical and mechanical properties of the contacting surfaces. A continuous contact force model, based on the elastic Hertz theory, together with a dissipative term associated with the internal damping, is utilized to evaluate the intra-joint normal contact forces. The incorporation of the friction phenomenon, based on the classical Coulomb’s friction law, is also included in this study. The suitable contact force models are embedded into the dynamic equations of motion for the multibody systems. In the sequel of this process, the fundamental methods to deal with contact-impact events in mechanical systems are presented. Finally, two planar mechanisms with multiple revolute clearance joints are used to demonstrate the accuracy and efficiency of the presented approach and to discuss the main assumptions and procedures adopted. The effects of single versus multiple clearance revolute joints are discussed.

scholarly journals Dynamics of Multibody Systems With Spherical Clearance Joints

2005 ◽  
Author(s):  
P. Flores ◽  
J. Ambro´sio ◽  
J. C. P. Claro ◽  
H. M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Contact Forces ◽  
Force Model ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Dynamics Of Multibody Systems ◽  
The Impact

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.

scholarly journals A Study on the Dynamics of Spatial Mechanisms With Frictional Spherical Clearance Joints

2017 ◽  
Vol 12 (5) ◽  
Author(s):  
Filipe Marques ◽  
Fernando Isaac ◽  
Nuno Dourado ◽  
António Pedro Souto ◽  
Paulo Flores ◽  
...  
Keyword(s):  
Friction Force ◽  
Contact Process ◽  
Contact Forces ◽  
Force Model ◽  
Spherical Joint ◽  
Normal Contact ◽  
Clearance Joints ◽  
Dissipative Term ◽  
Contact Points ◽  
Spatial Mechanisms

An investigation on the dynamic modeling and analysis of spatial mechanisms with spherical clearance joints including friction is presented. For this purpose, the ball and the socket, which compose a spherical joint, are modeled as two individual colliding components. The normal contact-impact forces that develop at the spherical clearance joint are determined by using a continuous force model. A continuous analysis approach is used here with a Hertzian-based contact force model, which includes a dissipative term representing the energy dissipation during the contact process. The pseudopenetration that occurs between the potential contact points of the ball and the socket surface, as well as the indentation rate play a crucial role in the evaluation of the normal contact forces. In addition, several different friction force models based on the Coulomb's law are revisited in this work. The friction models utilized here can accommodate the various friction regimens and phenomena that take place at the contact interface between the ball and the socket. Both the normal and tangential contact forces are evaluated and included into the systems' dynamics equation of motion, developed under the framework of multibody systems formulations. A spatial four-bar mechanism, which includes a spherical joint with clearance, is used as an application example to examine and quantify the effects of various friction force models, clearance sizes, and the friction coefficients.

A Study on the Dynamics of Spatial Mechanisms With Frictional Spherical Clearance Joints

2016 ◽  
Author(s):  
Filipe Marques ◽  
Fernando Isaac ◽  
Nuno Dourado ◽  
António Pedro Souto ◽  
Paulo Flores ◽  
...  
Keyword(s):  
Friction Force ◽  
Contact Process ◽  
Contact Forces ◽  
Force Model ◽  
Spherical Joint ◽  
Normal Contact ◽  
Clearance Joints ◽  
Dissipative Term ◽  
Contact Points ◽  
Spatial Mechanisms

An investigation on the dynamic modeling and analysis of spatial mechanisms with spherical clearance joints including friction is presented. For this purpose, the ball and the socket which compose a spherical joint are modeled as two individual colliding components. The normal contact-impact forces that develop at the spherical clearance joint are determined by using a continuous force model. A continuous analysis approach is used here with a Hertzian based contact force model, which includes a dissipative term representing the energy dissipation during the contact process. The pseudo-penetration that occurs between the potential contact points of the ball and the socket surface, as well as the indentation rate play a crucial role in the evaluation of the normal contact forces. In addition, several different friction force models based on the Coulomb’s law are revisited in this work. The friction models utilized here can accommodate the various friction regimens and phenomena that take place at the contact interface between the ball and the socket. Both the normal and tangential contact forces are evaluated and included into the systems’ dynamics equation of motion, developed under the framework of multibody systems formulations. A spatial four bar mechanism, which includes a spherical joint with clearance, is used as an application example to examine and quantify the effects of various friction force models, clearance sizes, and the friction coefficients.

scholarly journals Dynamic Response of Multibody Systems With Multiple Clearance Joints

2011 ◽  
Author(s):  
Paulo Flores ◽  
Hamid M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Equations Of Motion ◽  
Physical And Mechanical Properties ◽  
Contact Forces ◽  
Force Model ◽  
Modeling And Analysis ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Dissipative Term

A general methodology for the dynamic modeling and analysis of planar multibody systems with multiple clearance joints is presented. The inter-connecting body components that constitute a real joint are modeled as colliding bodies, which dynamic behaviors are influenced by geometric, physical and mechanical properties of the contacting surfaces. A continuous contact force model, based on the elastic Hertz theory, together with a dissipative term, is used to evaluate the intra-joint contact forces. The incorporation of the friction, based on the classical Coulomb’s friction law, is also included. The suitable contact force models are embedded into the dynamic equations of motion for the multibody system. A simple mechanical system with multiple clearance joints is used to demonstrate the accuracy and efficiency of the presented approach and to discuss the main assumptions and procedures adopted. The effects of single versus multiple clearance joints are discussed.

scholarly journals Research on Dynamic Characteristic of Rudder Transmission System with Multiple Clearance Joints

2020 ◽  
Vol 38 (5) ◽  
pp. 994-1000
Author(s):  
Qi Wan ◽  
Geng Liu ◽  
Chunyu Song ◽  
Shangjun Ma ◽  
Ruiting Tong
Keyword(s):  
Contact Force ◽  
Axial Length ◽  
Contact Process ◽  
Transmission System ◽  
Force Model ◽  
Heavy Load ◽  
Normal Contact ◽  
Clearance Joints ◽  
Contact Force Model ◽  
Structural Optimization And Control

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.

Study of the Dynamic Performance of Mechanical Systems With Multi-Clearance Joints

2010 ◽  
Author(s):  
S. M. Megahed ◽  
A. F. Haroun
Keyword(s):  
Contact Force ◽  
Dynamic Performance ◽  
Mechanical Systems ◽  
Local Deformation ◽  
Elastic Behavior ◽  
Contact Period ◽  
Clearance Joints ◽  
Coulomb’S Friction ◽  
Energy Dissipated ◽  
Maximum Impact Force

Joints’ clearance in mechanical systems such as linkage mechanisms and robots is an inevitable matter due to wear of mating parts. The presence of such clearance is a main source of impact forces resulting local deformation, wear and tear of such joints and consequently degradation of system performance. In this investigation, the effect of revolute joints’ clearance on the dynamic performance of mechanical systems is reported. The contact force between the pin (journal) and the bearing of the joint is modeled using Coulomb’s friction law, and contact force approach. This approach takes into consideration the elastic behavior of the collided bodies and the energy dissipated due to collision during the contact period. A computation algorithm is developed with the aid of SolidWorks/CosmosMotion software package. A crank-slider mechanism with one and two clearance-joints working in horizontal or vertical planes is studied. The simulation results point out that the presence of such clearance in the joints of the system understudy leads to high peaks in the characteristic curves of its dynamic and kinematic performance. The amplitudes of these peaks become higher as the number of clearance-joints included in the mechanism increases. For a multi-clearance joints mechanism, the maximum impact force at its joints takes its highest value at the nearest joint to the input link. This study also shows that, when the mechanism works in horizontal plane, the rate of impacts at each clearance-joint increases and consequently the clearance-joints and actuators will deteriorate faster. This means that working of the real mechanisms in vertical plan is more advantageous and improves their performance.

scholarly journals Modeling and Simulation for Wear Prediction in Planar Mechanical Systems with Multiple Clearance Joints

2021 ◽  
Author(s):  
Bo Li ◽  
Min San Wang ◽  
Charis J Gantes ◽  
Xuan U Tan
Keyword(s):  
Contact Surface ◽  
Mechanical Systems ◽  
Contact Forces ◽  
Force Model ◽  
Wear Depth ◽  
Contact Conditions ◽  
Clearance Joints ◽  
Effective Contact ◽  
Nonlinear Contact ◽  
Driving Condition

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.

scholarly journals Dynamics of Multibody Systems With Spherical Clearance Joints

2006 ◽  
Vol 1 (3) ◽  
pp. 240-247 ◽  
Author(s):  
P. Flores ◽  
J. Ambrósio ◽  
J. C. P. Claro ◽  
H. M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Contact Forces ◽  
Force Model ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Dynamics Of Multibody Systems ◽  
The Impact

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, with 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, with 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.

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