A New Contact Force Model for Low Coefficient of Restitution Impact

2012 ◽  
Vol 79 (6) ◽  
Author(s):  
Mohamed Gharib ◽  
Yildirim Hurmuzlu
Keyword(s):  
Contact Force ◽  
Contact Stiffness ◽  
Coefficient Of Restitution ◽  
Force Model ◽  
Reference Case ◽  
Practical Applications ◽  
Contact Force Model ◽  
Post Impact ◽  
Impact Problems ◽  
The Impact

Impact problems arise in many practical applications. The need for obtaining an accurate model for the inelastic impact is a challenging problem. In general, two approaches are common in solving the impact problems: the impulse-momentum and the compliance based methods. The former approach included the coefficient of restitution which provides a mechanism to solve the problem explicitly. While the compliance methods are generally tailored to solve elastic problems, researchers in the field have proposed several mechanisms to include inelastic losses. In this paper, we present correlations between the coefficient of restitution in the impulse-momentum based method and the contact stiffness in the compliance methods. We conducted numerical analysis to show that the resulting solutions are indeed identical for a specific range of impact conditions. The impulse-momentum based model is considered as a reference case to compare the post impact velocities. The numerical results showed that, the impulse-momentum and the compliance based methods can produce similar outcomes for specific range of coefficient of restitution if they satisfied a set of end conditions. The correlations lead to introduce a new contact force model with hysteresis damping for low coefficient of restitution impact.

An improved compliant contact force model using a piecewise function for impact analysis in multibody dynamics

2020 ◽  
Vol 234 (2) ◽  
pp. 424-432
Author(s):  
Jie Yu ◽  
Jinkui Chu ◽  
Yang Li ◽  
Le Guan
Keyword(s):  
Contact Force ◽  
Impact Analysis ◽  
Numerical Solutions ◽  
Contact Process ◽  
Coefficient Of Restitution ◽  
Force Model ◽  
Actual Situation ◽  
Contact Force Model ◽  
Piecewise Function ◽  
Impact Problems

Contact-impact problems have attracted more and more attention in mechanical multibody systems. In the past period of time, a few compliant contact force models have been put forward. However, some compliant contact force models are only applicable to a specific range of coefficient of restitution impact problems. And, some compliant contact force models have large errors with the actual situation. In order to reduce the errors, an improved compliant contact force model is proposed in this paper, which is applicable to the whole range of coefficient of restitution impact problems. In this work, the permanent deformation is taken into account during the contact process. Meanwhile, the method of piecewise fitting is used to reduce the errors in numerical solutions. Therefore, the improved compliant contact force model uses a piecewise function for the whole range of coefficient of restitution. In order to illustrate the situation, six independent contact force models are numerically analyzed by using Matlab codes. The result shows that the improved compliant contact force model in this paper is applicable to both soft and hard impact and nearer to the actual situation.

Correlation Between Impulse and Compliance Based Methods in Rigid Body Collisions

2011 ◽  
Author(s):  
Mohamed Gharib ◽  
Yidirim Hurmuzlu
Keyword(s):  
Numerical Analysis ◽  
Contact Stiffness ◽  
Coefficient Of Restitution ◽  
Challenging Problem ◽  
Practical Applications ◽  
Inelastic Impact ◽  
Wide Range ◽  
End Conditions ◽  
Impact Problems ◽  
The Impact

Impact problems arise in many practical applications. The need of obtaining an accurate model for the inelastic impact is a challenging problem. In general, two approaches are common in solving the impact problems: the impulse-momentum and the compliance based methods. The former approach included the coefficient of restitution which provides a mechanism to solve the problem explicitly. While the compliance methods are generally tailored to solve elastic problems, researchers in the field have proposed several mechanisms to include inelastic losses. In this paper, we present a correlation between the coefficient of restitution in the impulse-momentum based method and the contact stiffness in the compliance methods. We conducted numerical analysis to show that the resulting solutions are indeed identical for a wide range of impact conditions. The numerical results showed that, the two methods can produce similar outcomes if they satisfied a set of end conditions.

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 continuous contact force model of planar revolute joint based on fitting method

2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769047
Author(s):  
Yuntao Li ◽  
Qiquan Quan ◽  
Dewei Tang ◽  
Zhonghong Li ◽  
Zongquan Deng
Keyword(s):  
Contact Force ◽  
Contact Stiffness ◽  
Elastic Force ◽  
Contact Model ◽  
Force Model ◽  
Damping Force ◽  
Revolute Joint ◽  
Continuous Contact ◽  
Contact Force Model ◽  
Fitting Method

Both the process of eliminating the clearance in joints and the contact–impact process involve movement of a clearance mechanism, which may reduce transmission accuracy and lengthen the response time. An appropriate continuous contact force model is able to describe the contact phenomena of a joint with clearance in a facile manner. However, two main problems still should be solved in building the continuous contact force model. First, the elastic force parts in previous continuous contact force models for a revolute joint were established by amending the force exponent of the Hertz spherical contact model or by the modified Winkler contact model. Nevertheless, the force exponent is usually given by experience, and the thickness of the elastic layer in the Winkler theory is difficult to determine. Second, for the previous damping force parts of a revolute joint, the hysteretic damping coefficients were obtained by substituting the stiffness coefficient with the contact stiffness of revolute joint directly instead of using the energy conservation method for the complicated form of elastic force model. A feasible continuous contact force model based on a fitting method was proposed to avoid these problems. According to the experimental results, the continuous contact force model can be used to predict the contact characteristics of a planar revolute joint in a facile manner.

A Contact Force Model With Hysteresis Damping for Impact Analysis of Multibody Systems

1989 ◽  
Author(s):  
H. M. Lankarani ◽  
P. E. Nikravesh
Keyword(s):  
Contact Force ◽  
Impact Analysis ◽  
Multibody System ◽  
Particle Collision ◽  
Dissipated Energy ◽  
Particle Model ◽  
Force Model ◽  
Continuous Contact ◽  
Contact Force Model ◽  
The Impact

Abstract A continuous contact force model for the impact analysis of a two-particle collision is presented. The model uses the general trend of the Hertz contact law. A hysteresis damping function is encorporated in the model which represents the dissipated energy in impact. The parameters in the model are determined, and the validity of the model is established. The model is then generalized to the impact analysis between two bodies of a multibody system. A continuous analysis is performed using the equations of motion of either the multibody system or an equivalent two-particle model of the colliding bodies. For the latter, the concept of effective mass is presented in order to compensate for the effects of joint forces in the system. For illustration, the impact situation between a slider-crank mechanism and another sliding block is considered.

scholarly journals Modeling and analysis of impact based on numerical and experimental approaches

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881306
Author(s):  
Xupeng Wang ◽  
Yan Zhang ◽  
Zhu Gao ◽  
Xiaomin Ji ◽  
Lin Li
Keyword(s):  
Mechanical System ◽  
Contact Force ◽  
Impact Force ◽  
Numerical Results ◽  
Experimental Results ◽  
Force Model ◽  
Restitution Coefficient ◽  
Contact Force Model ◽  
Improved Model ◽  
The Impact

Impact is a universal phenomenon and has serious influences on the dynamic characteristics of mechanical system, so it is critical to accurately describe the effects of impact. In this work, a numerical and comprehensive method is presented to calculate the impact force in clearance joint during impact process, which has higher effectiveness and accuracy than the most popular used L-N model. Different from traditional contact models, where the coefficient of restitution is assumed to be a constant value nearly to 1 during impact process, the improved model in this work sets up the model of restitution coefficient related to two important parameters for impact phenomenon, which are initial impact velocity and the yield strength of the materials in clearance joints. A great number of numerical and experimental results are introduced and compared to validate the improved contact force model; it needs to be highlighted that the numerical results are based on the improved model and the most popular impact force model presented by Lankarani and Nikravesh, and the experimental results are based on two typical pendulum experimental test rigs. It can be concluded that (1) when compared to the experimental results, the numerical results based on the improved model are in better agreement than those based on Lankarani and Nikravesh impact force model; (2) the numerical results based on the improved model are in reasonable agreement with the experimental results, and the relative errors of impact force and restitution coefficient are all no more than 10% between numerical and experimental results; and (3) the improved contact force model is effective and can exactly describe the impact effects between two bodies in mechanical system.

A Realistic Model for Visco-Elastic Contact Between Spherical Particles

2006 ◽  
Author(s):  
Mohammad Hadi Bordbar ◽  
Timo Hyppanen
Keyword(s):  
Finite Elements ◽  
Contact Force ◽  
Coefficient Of Restitution ◽  
Spherical Particles ◽  
Experimental Result ◽  
Size Difference ◽  
Force Model ◽  
Elastic Contact ◽  
Contact Force Model ◽  
Finite Elements Model

The contact force model is very important to describe the grain collision process accurately. In this research, the linear/nonlinear contact force models and normal coefficient of restitution in different impact velocities has been studied. A new contact force model for describing the normal collision between two visco-elastic spherical particles has been suggested and the ability of this new model in predicting the correct behavior of normal contact has been confirmed. The constitutive equations of this model have been solved numerically and the result shows a better conformity with experimental result reported by Bridge et al. [1] than the previous models, such as the model presented by Brilliantov et al. [2]. By using the suitable finite elements model, the stress and deformation of particles during the collision has been obtained and the result of the finite elements model shows a good conformity with our new suggested contact force model in the case of elastic and visco-elastic contact. The behavior of normal coefficient of restitution in multisize spherical particles in different impact velocities and effect of the size on it has been experimentally studied. In addition to our more suitable contact force model, we achieved some nice conclusions from our experimental data about the loss of energy during the multisize collision and effect of size difference on this loss.

A novel contact force model for the impact analysis of structures with coating and its experimental verification

2016 ◽  
Vol 70-71 ◽  
pp. 1056-1072 ◽  
Author(s):  
Dengqing Cao ◽  
Yang Yang ◽  
Huatao Chen ◽  
Deyou Wang ◽  
Guangyi Jiang ◽  
...  
Keyword(s):  
Contact Force ◽  
Experimental Verification ◽  
Impact Analysis ◽  
Force Model ◽  
Contact Force Model ◽  
The Impact

A Contact Force Model With Hysteresis Damping for Impact Analysis of Multibody Systems

1990 ◽  
Vol 112 (3) ◽  
pp. 369-376 ◽  
Author(s):  
H. M. Lankarani ◽  
P. E. Nikravesh
Keyword(s):  
Contact Force ◽  
Impact Analysis ◽  
Multibody System ◽  
Particle Collision ◽  
Dissipated Energy ◽  
Particle Model ◽  
Force Model ◽  
Continuous Contact ◽  
Contact Force Model ◽  
The Impact

A continuous contact force model for the impact analysis of a two-particle collision is presented. The model uses the general trend of the Hertz contact law. A hysteresis damping function is incorporated in the model which represents the dissipated energy in impact. The parameters in the model are determined, and the validity of the model is established. The model is then generalized to the impact analysis between two bodies of a multibody system. A continuous analysis is performed using the equations of motion of either the multibody system or an equivalent two-particle model of the colliding bodies. For the latter, the concept of effective mass is presented in order to compensate for the effects of joint forces in the system. For illustration, the impact situation between a slider-crank mechanism and another sliding block is considered.

Validation of Nonlinear Viscoelastic Contact Force Models for Low Speed Impact

2009 ◽  
Vol 76 (5) ◽  
Author(s):  
Yuning Zhang ◽  
Inna Sharf
Keyword(s):  
Contact Force ◽  
Nonlinear Damping ◽  
Coefficient Of Restitution ◽  
Contact Dynamics ◽  
Dynamics Simulation ◽  
Damping Coefficient ◽  
Force Model ◽  
Nonlinear Viscoelastic ◽  
The Impact ◽  
Viscoelastic Contact

Compliant contact force modeling has become a popular approach for contact and impact dynamics simulation of multibody systems. In this area, the nonlinear viscoelastic contact force model developed by Hunt and Crossley (1975, “Coefficient of Restitution Interpreted as Damping in Vibroimpact,” ASME J. Appl. Mech., 42, pp. 440–445) over 2 decades ago has become a trademark with applications of the model ranging from intermittent dynamics of mechanisms to engagement dynamics of helicopter rotors and implementations in commercial multibody dynamics simulators. The distinguishing feature of this model is that it employs a nonlinear damping term to model the energy dissipation during contact, where the damping coefficient is related to the coefficient of restitution. Since its conception, the model prompted several investigations on how to evaluate the damping coefficient, in turn resulting in several variations on the original Hunt–Crossley model. In this paper, the authors aim to experimentally validate the Hunt–Crossley type of contact force models and furthermore to compare the experimental results to the model predictions obtained with different values of the damping coefficient. This paper reports our findings from the sphere to flat impact experiments, conducted for a range of initial impacting velocities using a pendulum test rig. The unique features of this investigation are that the impact forces are deduced from the acceleration measurements of the impacting body, and the experiments are conducted with specimens of different yield strengths. The experimental forces are compared with those predicted from the contact dynamics simulation of the experimental scenario. The experiments, in addition to generating novel impact measurements, provide a number of insights into both the study of impact and the impact response.

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