Analysis of a Compliant Honing Tool for Brushing Cylindrical Surfaces

1997 ◽  
Vol 119 (3) ◽  
pp. 441-444 ◽  
Author(s):  
Chih-Yuan Shia ◽  
R. J. Stango
Keyword(s):  
Steady State ◽  
Contact Force ◽  
Rotational Speed ◽  
Cylindrical Surface ◽  
Dynamic Contact ◽  
Contact Forces ◽  
Spherical Volume ◽  
Special Cases ◽  
Flexible Honing ◽  
State Configuration

In this paper, a mechanics-based model is developed and I used for analyzing the steady-state configuration of brush fibers during concentric brushing of a cylindrical surface. The geometry of the problem is generalized in order to facilitate the analysis of flexible honing tools, that is, brushing tools having a spherical volume of abrasive compound attached at the end of each fiber. The integrity of the model is evaluated by examining two special cases that have a known solution, namely, (i) quasistatic contact, and (ii) dynamic contact associated with successively reduced fiber stiffness. In each case, correct results are obtained for the contact forces generated at the interface of the filament tip/cylindrical workpart surface. Also, special attention is given to examining the role that brush rotational speed plays in the response of each fiber of the honing tool, including filament/workpart contact force, torque, and filament stress.

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>

Wheel–Rail Impact at Crossings: Relating Dynamic Frictional Contact to Degradation

2017 ◽  
Vol 12 (4) ◽  
Author(s):  
Zilong Wei ◽  
Chen Shen ◽  
Zili Li ◽  
Rolf Dollevoet
Keyword(s):  
Plastic Deformation ◽  
Contact Force ◽  
Frictional Contact ◽  
Point Contact ◽  
Strain Analysis ◽  
Dynamic Contact ◽  
Contact Forces ◽  
Fe Method ◽  
Normal Contact ◽  
The Impact

Irregularities in the geometry and flexibility of railway crossings cause large impact forces, leading to rapid degradation of crossings. Precise stress and strain analysis is essential for understanding the behavior of dynamic frictional contact and the related failures at crossings. In this research, the wear and plastic deformation because of wheel–rail impact at railway crossings was investigated using the finite-element (FE) method. The simulated dynamic response was verified through comparisons with in situ axle box acceleration (ABA) measurements. Our focus was on the contact solution, taking account not only of the dynamic contact force but also the adhesion–slip regions, shear traction, and microslip. The contact solution was then used to calculate the plastic deformation and frictional work. The results suggest that the normal and tangential contact forces on the wing rail and crossing nose are out-of-sync during the impact, and that the maximum values of both the plastic deformation and frictional work at the crossing nose occur during two-point contact stage rather than, as widely believed, at the moment of maximum normal contact force. These findings could contribute to the analysis of nonproportional loading in the materials and lead to a deeper understanding of the damage mechanisms. The model provides a tool for both damage analysis and structure optimization of crossings.

scholarly journals Design and Calibration of a Tri-Directional Contact Force Measurement System

2021 ◽  
Vol 11 (2) ◽  
pp. 877
Author(s):  
Rizwan Ahmed ◽  
Christian Maria Firrone ◽  
Stefano Zucca
Keyword(s):  
Contact Force ◽  
Measurement System ◽  
Force Measurement ◽  
Three Dimensional ◽  
Dynamic Contact ◽  
Forced Response ◽  
Contact Forces ◽  
Blade Vibration ◽  
Contact Models ◽  
Force Measurement System

In low pressure turbine stages, adjacent blades are coupled to each other at their tip by covers, called shrouds. Three-dimensional periodic contact forces at shrouds strongly affect the blade vibration level as energy is dissipated by friction. To validate contact models developed for the prediction of nonlinear forced response of shrouded blades, direct contact force measurement during dynamic tests is mandatory. In case of shrouded blades, the existing unidirectional and bi-directional contact force measurement methods need to be improved and extended to a tri-directional measurement of shroud contact forces for a comprehensive and more reliable validation of the shroud contact models. This demands an accurate and robust measurement solution that is compatible with the nature and orientation of the contact forces at blade shrouds. This study presents a cost effective and adaptable tri-directional force measurement system to measure static and dynamic contact forces simultaneously in three directions at blade shrouds during forced response tests. The system is based on three orthogonal force transducers connected to a reference block that will eventually be put in contact with the blade shroud in the test rig. A calibration process is outlined to define a decoupling matrix and its subsequent validation is demonstrated in order to evaluate the effectiveness of the measurement system to measure the actual contact forces acting on the contact.

Predicting Fly-Height Modulation and Contact Forces in Ultra-Low Flying Head-Disk Interfaces Using a Tri-State Switching Dynamic Contact Model

2001 ◽  
Author(s):  
Sung-Chang Lee ◽  
Andreas A. Polycarpou
Keyword(s):  
Contact Force ◽  
Contact Stiffness ◽  
Dynamic Contact ◽  
Design Guidelines ◽  
Contact Forces ◽  
Contact Dynamics ◽  
Contact Model ◽  
Flying Height ◽  
Disk Contact ◽  
Fly Height

Abstract In order to achieve higher recording densities up to 1 Tbit/In2 using conventional recording technologies, the recording slider will need to “fly” within 5 nm or less from the rotating disk. In such ultra-low flying height regimes, intermittent head/disk contact is unavoidable. Head/disk contact can cause large vibrations of the recording slider in the normal and lateral (off-track) directions as well as damage the disk due to large dynamic contact forces. This paper describes a simple continuum mechanics-based model that includes the dynamics of a flying head/disk interface (HDI) as well as the contact dynamics. Specifically, a lumped parameter one degree-of-freedom, three state nonlinear dynamic model representing the normal dynamics of the HDI and an asperity-based contact model are developed. The effects of realistic (dynamic microwaviness) and harmonic input excitations, contact stiffness (surface roughness) and air-bearing force during contact on fly-height modulation (FHM) and contact force are investigated. Based on the tri-state model predictions, design guidelines for reduced FHM and dynamic contact force are suggested.

Analysis of Forces Acting on Compressor Sliding Vanes

2002 ◽  
Author(s):  
Yuan Mao Huang ◽  
Chien Liang Li
Keyword(s):  
Contact Force ◽  
Rotational Speed ◽  
Contact Forces ◽  
Outlet Port ◽  
Newton's Law ◽  
Newton’S Law ◽  
To Come ◽  
Starting Location

This study utilizes Newton’s law to analyze: 1) the force required to act on a vane bottom in order to create zero contact force between the vane and the stator, and 2) the contact forces between the vane and the rotor in a sliding vane compressor. The effects of the number, length, thickness and material of vanes, the locations of the outlet ports, and the rotor rotational speed of the compressor on these forces are analyzed. The results show that the effect of the vane thickness on these forces is not significant. Nevertheless, these forces increase when the number of vanes and the angular starting location of the outlet port increases. When the length and the density of the vane and the rotational speed of the rotor increase, there is a decrease in the force required to act on the vane bottom in order for it to come in to contact with the stator.

A Computational Fluid Dynamics Methodology for Predicting Aeration in Wet Friction Clutches

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Irsha Pardeshi ◽  
Tom I-P. Shih
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Contact Angle ◽  
Steady State ◽  
Rotational Speed ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Drag Torque ◽  
Wet Friction ◽  
Cfd Method

Computational fluid dynamics (CFD) has been unable to reliably predict aeration and drag torque in clutches. In this study, a CFD method was developed to reliably predict the onset of aeration and drag torque as a function of the clutch's rotational speed. This study showed that though the oil and air behave as if they are incompressible at steady-state, the formulation must account for the compressible nature of the gas and the unsteady processes that occur before reaching steady-state. This study also showed that the dynamic nature of the contact angle between the oil and the stationary disk must be accounted for to predict drag torque and aeration as a function of rotational speed, and a model of the dynamic-contact angle was developed.

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.

Periodic Response of a Link Coupling With Clearance

1989 ◽  
Vol 111 (2) ◽  
pp. 253-259 ◽  
Author(s):  
Y. S. Choi ◽  
S. T. Noah
Keyword(s):  
Steady State ◽  
Boundary Conditions ◽  
Solution Procedure ◽  
Contact Forces ◽  
Steady State Response ◽  
Algebraic Equations ◽  
State Response ◽  
Contact Points ◽  
Integration Schemes ◽  
Nonlinear Algebraic Equations

The nonlinear, steady-state response of a displacement-forced link coupling with clearance with finite stiffness is determined. The solution procedure is derived from satisfying the boundary conditions at the contact points and then solving the resulting nonlinear algebraic equations by setting the duration of contact as a parameter. This direct approach to determining periodic solutions for systems with clearances with finite stiffness is substantially more efficient than numerical integration schemes. Results in terms of contact forces and durations of contact are pertinent to fatigue and wear studies. Parametric relations are presented for effects of the variation of damping, stiffness, exciting displacement, and gap length on the dynamic behavior of the link pair.

Contact force analysis on two-fingered robot grasping

2020 ◽  
pp. 146441932096402
Author(s):  
Jiun-Ru Chen ◽  
Wei-En Chen ◽  
CH Liu ◽  
Yin-Tien Wang ◽  
CB Lin ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Contact Force ◽  
Numerical Procedure ◽  
Spherical Body ◽  
Solution Procedure ◽  
The Body ◽  
Contact Forces ◽  
Grasping Forces ◽  
Robot Grasping ◽  
Force Displacement

A procedure for inverse kinetic analysis on two hard fingers grasping a hard sphere is proposed in this study. Contact forces may be found for given linear and angular accelerations of a spherical body. Elastic force-displacement relations predicted by Hertz contact theory are used to remove the indeterminancy produced by rigid body modelling. Two types of inverse kinetic analysis may be dealt with. Firstly, as the fingers impose a given tightening displacement on the body, and carry it to move with known accelerations, corresponding grasping forces may be determined by a numerical procedure. In this procedure one contact force may be chosen as the principal unknown, and all other contact forces are expressed in terms of this force. The numerical procedure is hence very efficient since it deals with a problem with only one unknown. The solution procedure eliminates slipping thus only nonslip solutions, if they exist, are found. Secondly, when the body is moving with known accelerations, if the grasping direction of the two fingers is also known, then the minimum tightening displacement required for non-sliding grasping may be obtained in closed form. In short, the proposed technique deals with a grasping system that has accelerations, and in this study the authors show that indeterminancy may be used to reduce the complexity of the problem.

Sign in / Sign up

Export Citation Format

Share Document