scholarly journals Analytical Study of Babbitt/steel Composite Structural Bars in Oblique Contact-impact with a Solid Flat Surface

2019 ◽  
Vol 10 (1) ◽  
pp. 213-228 ◽  
Author(s):  
Yao Wang ◽  
Zhuang Fu
Keyword(s):  
Angular Velocity ◽  
Contact Force ◽  
Flat Surface ◽  
Permanent Deformation ◽  
Coefficient Of Restitution ◽  
Contact Forces ◽  
Experimental Results ◽  
Impact Behavior ◽  
Contact Impact ◽  
Weak Material

Abstract. The oblique contact-impact characteristic of the composite structural bar composed of Babbitt alloy and low-carbon steel (ZChSbSb11-6 ∕ AISI 1020) with a solid flat surface (AISI 1045) was studied theoretically and experimentally. The dynamic equation of the composite structural bar with vibration response during the contact-impact was established using the momentum theorem and assumed mode method, and the instantaneous contact forces during different impact phases were analyzed based on modified Jackson–Green model. Four sets of experiments (i.e. different proportion of Babbitt, ξ={1/8,1/2,3/4,7/8}) for the initial angle, θ=45∘, and different initial velocities were performed; and, the rebound linear and angular velocity of the contact point of composite structural bar after impact was calculated and compared with experimental results. Besides, the coefficient of restitution, the relation of contact force and contact deflection, and the permanent deformation were also compared for the composite structural bars with different proportions in combination, ξ. Three critical angles are found to determine whether the composite bar slides or not, but are prominently different for the composite bars with different ξ. In comparing with the experimental results, the numerical solutions of rebound linear and angular velocity had yield encourage results and, all relative errors were small, indicating that the simulations are in good agreement with the experimental results. Also, the oblique contact-impact behavior involving the coefficient of restitution, the relation of contact force and contact deflection, and the permanent deformation was explained in detail. It can be concluded that as the proportion of Babbitt ξ increases, the composite structural bar presents a characteristic of ease of deflection. And the contact-impact behavior of structural entity is closely related to the inherent properties of the elasto-plastic material, especially for the weak material of composite structures. The more easily the impacting object is deformed, the small the contact force during the contact-impact, which also indicates the yield strength of weak material is a very significant parameter in the event of collision. Such work could give conducive insights to contact-impact problems of the key parts or structures composed of composite materials in mechanical system.

Experimental and theoretical analyses of the contact-impact behavior of Babbitt ZChSnSb11-6

2017 ◽  
Vol 233 (7) ◽  
pp. 1267-1276 ◽  
Author(s):  
Yao Wang ◽  
Shujun Li ◽  
Dan Xiang ◽  
Wenjun Meng
Keyword(s):  
Contact Force ◽  
Numerical Solutions ◽  
Permanent Deformation ◽  
Absolute Error ◽  
Coefficient Of Restitution ◽  
Experimental Results ◽  
Impact Behavior ◽  
Impact Model ◽  
Oil Film ◽  
Contact Impact

Contact-impact between Babbitt and steel surfaces is an ubiquitous phenomenon during the operation of oil-film bearing. To study this phenomenon, a contact-impact method of Babbitt ZChSnSb11-6 was designed and the contact-impact test was performed. For the purpose of getting a more complete understanding of the contact-impact mechanical properties of Babbitt ZChSnSb11-6, the relationships of coefficient of restitution, permanent deformation, and drop height (i.e. the initial impact velocity) were analyzed; and, the constitutive behavior between the contact force and the contact deflection was studied. Then, based on the empirical formulation developed by Brake, an indentation contact-impact model during impact events was established, which theoretically explained the contact-impact behavior of Babbitt ZChSnSb11-6. Meanwhile, the experimental results were compared with the numerical solutions solved by using MATLAB. Results revealed the established model shows a good agreement with the experimental results. The mean absolute error of coefficient of restitution was less than 0.025, and the difference for the permanent deformation after impact was less than 1%. For the contact-impact tests with different size parameters, the length and the diameter of 20 steel rods were the two significant influencing factors on the permanent deformation and coefficient of restitution of Babbitt flat surface; and, the relationship of contact force and contact deflection appeared to display the similar trend. It was concluded that the established contact-impact model has the effectiveness and applicablility on describing its contact-impact behaviors, and which can provide theoretical and experimental supports for the prediction of contact deflection and contact force of the Babbitt ZChSnSb11-6 of oil-film bearing.

Predicting the Permanent Deformation After the Impact of a Rod With a Flat Surface

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Hamid Ghaednia ◽  
Dan B. Marghitu ◽  
Robert L. Jackson
Keyword(s):  
Flat Surface ◽  
Impact Force ◽  
Permanent Deformation ◽  
Element Model ◽  
Coefficient Of Restitution ◽  
Experimental Results ◽  
Normal Impact ◽  
Previous Contact ◽  
Contact Models ◽  
The Impact

In this study, a new expression for the permanent deformation after the impact of a rod with a flat surface is given. Both flat and the surface have been considered elastoplastic. The contact has been considered frictionless and has been divided into three phases, the elastic, the elastoplastic, and the unloading phase. For the normal impact force in the loading phase, we considered a nonlinear expression that satisfies the effect of deformation on both objects by using a finite element model. For the unloading phase, the contact force has been considered to follow the Hertz theory. The simulation and experimental results were conducted for different initial impact velocities of the rod. Permanent deformation after the impact and the motion of the rod has been measured accurately in the experiments. Based on the simulation and experimental results an expression for the permanent deformation has been developed. Finally, the model has been verified and compared with previous contact models in terms of the coefficient of restitution.

SIMULATION OF DYNAMIC EVENT OF IMPACT USING EXPLICIT 3D FEM MODEL AND VALIDATION BY EXPERIMENT AND CONTACT MODELS

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Akshay Mallikarjuna ◽  
Dan Marghitu ◽  
P.K. Raju
Keyword(s):  
Material Properties ◽  
Permanent Deformation ◽  
Oblique Impact ◽  
Coefficient Of Restitution ◽  
Impact Behavior ◽  
3D Fem ◽  
Dynamic Event ◽  
Contact Models ◽  
Explicit Dynamic ◽  
The Impact

— In this study, an optimized method to simulate the dynamic 3D event of the impact of a rod with a flat surface has been presented. Unlike the 2D FEM based contact models, in this study both the bodies undergoing the impact are considered elastic(deformable) and simulation is the dynamic event of the impact, instead of predefined 2D symmetric contact analysis. Prominent contact models and plasticity models to define material properties in ANSYS are reviewed. Experimentation results of normal and oblique impact of the rod for different rods provided the coefficient of restitution. Experimental results of permanent deformation on the base for different impact velocity is derived out of a prominent impact study. The simulation results are in co-relation with experiment and both indentation and flattening models on the coefficient of restitution (COR) and permanent deformation of the base and rod after the impact. Thus, the presented 3D Explicit Dynamic simulation of impact is validated to analyze the impact behavior of the 2 bodies without any predefined assumptions with respect to boundary conditions or material properties.

Analytical Study of the Oblique Impact of a Rod with a Flat Using an Elasto-Plastic Contact Model

2015 ◽  
Vol 801 ◽  
pp. 25-32
Author(s):  
Ozdes Cermik ◽  
Hamid Ghaednia ◽  
Dan B. Marghitu
Keyword(s):  
Impact Velocity ◽  
Contact Force ◽  
Analytical Study ◽  
Initial Conditions ◽  
Permanent Deformation ◽  
Oblique Impact ◽  
Coefficient Of Restitution ◽  
Contact Model ◽  
Impact Angles ◽  
The Impact

In the current study a flattening contact model, combined with a permanent deformation expression, has been analyzed for the oblique impact case. The model has been simulated for different initial conditions using MATLAB. The initial impact velocity used for the simulations ranges from 0.5 to 3 m/s. The results are compared theoretically for four different impact angles including 20, 45, 70, and 90 degrees. The contact force, the linear and the angular motion, the permanent deformation, and the coefficient of restitution have been analyzed. It is assumed that sliding occurs throughout the impact.

An Overview on Continuous Contact Force Models for Multibody Dynamics

2012 ◽  
Author(s):  
Paulo Flores ◽  
Hamid M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Contact Forces ◽  
Hertz Contact ◽  
Dynamic Simulations ◽  
Ball Impact ◽  
Continuous Contact ◽  
Multibody Dynamic ◽  
Contact Impact ◽  
Impact Events

The nature of the constitutive contact force law utilized to describe contact-impact events plays a crucial role in predicting the dynamic response of multibody systems. The main goal of this work is present a survey of the literature on the most relevant penalty-force based approaches for multibody dynamic simulations. In this process, the fundamental characteristics of the purely elastic and the dissipative contact force models are analyzed, namely the models which have been developed based on the Hertz contact law. In particular, the different models are compared in this study for a simple impact problem for the sole purpose of comparison of the models and examining their validity compared to those from experiments. Results obtained for a classical ball impact on a massive surface are presented and used to discuss the main assumptions and procedures associated with the different penalty-force approaches. The force models are found to be quite well representative of the contact forces in an impact, and that they can be applied for the analysis of impact in more complex systems a such as the ones in planar and spatial multibody mechanical systems.

Comprehensive analyses of the elasto-plastic oblique contact-impact with vibration response

2018 ◽  
Vol 233 (2) ◽  
pp. 441-454 ◽  
Author(s):  
Wenjun Meng ◽  
Yao Wang
Keyword(s):  
Dynamic Modeling ◽  
Transverse Vibration ◽  
Flat Surface ◽  
Influence Factor ◽  
Contact Point ◽  
Vibration Response ◽  
Experimental Results ◽  
Vibration Responses ◽  
Contact Impact ◽  
The Impact

Contact-impact between different surfaces is a ubiquitous phenomenon especially in the mechanical systems. Previous work of authors indicated that the effect of longitudinal and/or transverse vibration response during the motion and dynamic modeling cannot be neglected for the elasto-plastic contact-impact events. In this study, further analyses were performed to characterize the contribution of longitudinal and transverse vibration responses during the elasto-plastic oblique contact-impact, and the formula to calculate the influence factor of vibration, ξ, was proposed based on the contact force with different vibrations during the impact. The momentum theorem and assumed mode method were used to develop the equations of motion of a flexible bar with a solid flat surface. Simulation results were compared with experimental results reported in the literature to verify the accuracy of the established model. The tangential and normal velocities of the contact point after the impact were compared with the simulations for different vibration cases, and the comparison between the simulations and the experimental results had yield encourage results. For different elasto-plastic materials, three critical initial impact angles had been found from the simulation to determine whether the flexible bar slides or sticks the flat surface. Although considering the effect of vibration response during the motion and dynamic modeling is very significant, increasing the number of shape functions did not effect the result significantly. The longitudinal and transverse vibration responses were found to effect the normal and tangential velocities of the contact point after the impact, respectively. Moreover, it had been shown that for the oblique contact-impact with sliding, considering the response of longitudinal and transverse vibration at the same time is more reasonable than other cases, which also reveals that, in this case, there is a good agreement between the simulation and experimental results. Besides, the mathematical expression on the influence factor of vibration depending on the initial velocity also had been obtained by a numerical analysis. This work can provide useful insights for dynamic modeling of complex multi-body systems during the contact-impact.

Impact of a Compound Pendulum With a Surface Using a Nonlinear Contact Force

2009 ◽  
Author(s):  
Eliza A. Banu ◽  
Dan Marghitu ◽  
Robert Jackson
Keyword(s):  
Contact Force ◽  
Flat Surface ◽  
Quantitative Measure ◽  
Coefficient Of Restitution ◽  
Contact Analysis ◽  
Plastic Compression ◽  
Nonlinear Contact ◽  
Angular Velocities ◽  
The Impact ◽  
Impact With Friction

The coefficient of restitution for the impact of a compound pendulum with a flat surface is an important quantitative measure in contact analysis. The impact is analyzed for different lengths of the pendulum, different angles of impact, and different initial angular velocities of the pendulum. The impact with friction is studied using an elasto plastic force developed by Jackson and Green for the three phases of impact: elastic compression, elasto-plastic compression, and elastic restitution phase.

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.

Modeling and Simulation of Clamp Band Dynamic Envelope in a LV/SC Separation System

2011 ◽  
Vol 141 ◽  
pp. 359-363 ◽  
Author(s):  
Jun Lan Li ◽  
Shao Ze Yan ◽  
Xue Feng Tan
Keyword(s):  
Friction Coefficient ◽  
Modeling And Simulation ◽  
Band System ◽  
Separation Process ◽  
Impact Behavior ◽  
Separation System ◽  
Lumped Mass ◽  
Lumped Mass Method ◽  
Simulation Results ◽  
Contact Impact

The clamp band system is a typical locked and separated device of the launch vehicle (LV) / the spacecraft (SC), and its release-separation process is one of the important factors that affect the LV/SC separation movement. A nonlinear spring-damper model was employed to describe the contact-impact behavior between the V-segment of the clamp band and the LV/SC interface, and lumped mass method was used to depict the clamp band. By using ADAMS, a dynamic model of the clamp band system was established. The simulation results show that the impulse of the explosive bolts and the stiffness of lateral-restraining springs have significant effects on the clamp band dynamic envelope. The shock of the satellite-vehicle separation is very vulnerable to the clamp band pretension and the friction coefficient between the V-segment and the LV/SC interface.

Evaluation of vehicular contact force on bridge joints by vibration responses and object detection

2021 ◽  
Author(s):  
Di Su ◽  
Yuichiro Tanaka ◽  
Tomonori Nagayama
Keyword(s):  
Object Detection ◽  
Contact Force ◽  
Dynamic Contact ◽  
Contact Forces ◽  
Expansion Joints ◽  
Cyclic Movements ◽  
Bridge Joints ◽  
Vibration Responses ◽  
On The Road ◽  
Board System

<p>Expansion joints on bridges should accommodate cyclic movements to minimize imposition of secondary stresses in the structure. However, these joints are highly susceptible to severe and repeated vehicular impact that results their inherent discontinuity. In this paper, a portable on- board system including accelerometers and a drive recorder to evaluate the vehicular contact force on bridge joints is proposed. First, from the acceleration responses of the vehicle, the contact force exerted on the road surface is estimated from a half-car model by Kalman Filter. Next, extraction of the expansion joints is performed by object detection from videos taken by the drive recorder. Finally, a relative comparison of the contact forces acting on joints is performed, with location identification on the map. The proposed system benefits to utilize the dynamic contact forces results from on-board system to detect the potential risky joints more precisely and efficiently.</p>

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