A Physics-Based Fretting Model With Friction and Integration to a Simple Dynamical System

2011 ◽  
Author(s):  
Melih Eriten ◽  
Andreas A. Polycarpou ◽  
Lawrence A. Bergman
Keyword(s):  
First Principles ◽  
Lap Joints ◽  
Dynamical Response ◽  
Friction Modeling ◽  
Roughness Effects ◽  
Contact Conditions ◽  
Reduced Order ◽  
Interface Contact ◽  
Friction Models ◽  
Simple Dynamical System

Dynamical modeling and simulations of structures containing joint interfaces require reduced-order fretting models for efficiency. The reduced-order models in the literature compromise accuracy and physical basis of the modeling procedure, especially in regards to interface contact and friction modeling. Recently, physics-based fretting models for flat-on-flat contacts, including roughness effects have been developed and tested on individual (isolated) mechanical lap joints [1]. These models follow a “bottom up” modeling approach; utilizing the micromechanics of sphere-on-flat fretting contact (asperity scale), and statistical summation to model flat-on-flat contact (macroscale). Since these models are derived from first principles, the effects of surface roughness, contact conditions, and material properties on fretting and dynamical response of the jointed interfaces can be studied. The present work illustrates an example of how the physics-based models can be incorporated in dynamics of jointed structures. A comparison with the friction models existing in the literature is also provided.

A Physics-Based Friction Model and Integration to a Simple Dynamical System

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
M. Eriten ◽  
A. A. Polycarpou ◽  
L. A. Bergman
Keyword(s):  
Friction Model ◽  
Lap Joints ◽  
Dynamical Response ◽  
Friction Modeling ◽  
Roughness Effects ◽  
Contact Conditions ◽  
Reduced Order ◽  
Interface Contact ◽  
Friction Models ◽  
Simple Dynamical System

Dynamical modeling and simulation of mechanical structures containing jointed interfaces require reduced-order fretting models for efficiency. The reduced-order models in the literature compromise both accuracy and the physical basis of the modeling procedure, especially with regard to interface contact and friction modeling. Recently, physics-based fretting models for nominally flat-on-flat contacts, including roughness effects, have been developed and validated on individual (isolated) mechanical lap joints (Eriten et al., 2011, “Physics-Based Modeling for Fretting Behavior of Nominally Flat Rough Surfaces,” Int. J. Solids Struct., 48(10), pp. 1436-1450). These models follow a “bottom up” modeling approach; utilizing the micromechanics of sphere-on-flat fretting contact (asperity scale), and statistical summation to model flat-on-flat contacts at the macroscale. Since these models are physical, the effects of surface roughness, contact conditions, and material properties on fretting and dynamical response of the jointed interfaces can be studied. The present work illustrates an example of how the physics-based models can be incorporated into studies of the dynamics of jointed structures. A comparison with friction models existing in the literature is also provided.

Static Friction Models for Vehicle Simulation Study

2006 ◽  
Author(s):  
Xubin Song ◽  
Daniel G. Smedley
Keyword(s):  
Simulation Study ◽  
Static Friction ◽  
Friction Modeling ◽  
Stick Slip ◽  
Vehicle Simulation ◽  
Engineering Software ◽  
Variable Step ◽  
History Of ◽  
Friction Models ◽  
Smooth Dynamics

The history of the challenge of friction modeling is briefly reviewed. Then this paper focuses on the modeling and simulation study of the friction related dynamics in the Simulink® environment, because Matlab®/Simulink® are popular engineering software tools for both industry and academia. Matlab® and Simulink® are the proprietary products of MathWorks, Inc. In this paper, the static friction models are studied through Simulink® by applying fixed and variable step sizes. The comparison shows that the static Karnopp model is not only numerically tractable but also can be inclusive of the fundamental friction characteristics of both stick slip and correct friction predictions. Finally this paper presents an improved Karnopp model for clutch modeling with the use of Simulink®, and the simulation shows that this model is computationally tractable with smooth dynamics.

Stability Considerations in Thermoelastic Contact

1980 ◽  
Vol 47 (4) ◽  
pp. 871-874 ◽  
Author(s):  
J. R. Barber ◽  
J. Dundurs ◽  
M. Comninou
Keyword(s):  
Steady State ◽  
Perturbation Method ◽  
Energy Function ◽  
First Principles ◽  
Dimensional Model ◽  
Contact Conditions ◽  
One Dimensional ◽  
Thermoelastic Contact ◽  
The Stability ◽  
Steady State Solutions

A simple one-dimensional model is described in which thermoelastic contact conditions give rise to nonuniqueness of solution. The stability of the various steady-state solutions discovered is investigated using a perturbation method. The results can be expressed in terms of the minimization of a certain energy function, but the authors have so far been unable to justify the use of such a function from first principles in view of the nonconservative nature of the system.

Thermo-mechanical modelling of the Friction Stir Spot Welding process: Effect of the friction models on the heat generation mechanisms

2022 ◽  
pp. 146442072110709
Author(s):  
Nasra Hannachi ◽  
Ali Khalfallah ◽  
Carlos Leitão ◽  
Dulce Rodrigues
Keyword(s):  
Numerical Simulation ◽  
Heat Generation ◽  
Spot Welding ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Frictional Heat ◽  
Contact Conditions ◽  
Friction Stir ◽  
Friction Models ◽  
Generation Mechanisms

Friction Stir Spot Welding involves complex physical phenomena, which are very difficult to probe experimentally. In this regard, the numerical simulation may play a key role to gain insight into this complex thermo-mechanical process. It is often used to mimic specific experimental conditions to forecast outputs that may be substantial to analyse and elucidate the mechanisms behind the Friction Stir Spot Welding process. This welding technique uses frictional heat generated by a rotating tool to join materials. The heat generation mechanisms are governed by a combination of sliding and sticking contact conditions. In the numerical simulation, these contact conditions are thoroughly dependent on the used friction model. Hence, a successful prediction of the process relies on the appropriate selection of the contact model and parameters. This work aims to identify the pros and cons of different friction models in modelling combined sliding-sticking conditions. A three-dimensional coupled thermo-mechanical FE model, based on a Coupled Eulerian-Lagrangian formulation, was developed. Different friction models are adopted to simulate the Friction Stir Spot Welding of the AA6082-T6 aluminium alloy. For these friction models, the temperature evolution, the heat generation, and the plastic deformation were analysed and compared with experimental results. It was realized that numerical analysis of Friction Stir Spot Welding can be effective and reliable as long as the interfacial friction characteristics are properly modelled. This approach may be used to guide the contact modelling strategy for the simulation of the Friction Stir Spot Welding process and its derivatives.

Glitchless Static Friction Models in SIMULINK for Vehicle Simulation Study

2009 ◽  
Vol 5 (1) ◽  
Author(s):  
Xubin Song ◽  
Daniel G. Smedley
Keyword(s):  
Simulation Study ◽  
Static Friction ◽  
Friction Modeling ◽  
Stick Slip ◽  
Vehicle Simulation ◽  
Engineering Software ◽  
Variable Step ◽  
History Of ◽  
Friction Models ◽  
Smooth Dynamics

The history of the challenge of friction modeling is briefly reviewed. Then, this paper focuses on the modeling and simulation study of the friction related dynamics in the SIMULINK® environment, because MATLAB®/SIMULINK® are popular engineering software tools for both industry and academia. MATLAB® and SIMULINK® are the proprietary products of MathWorks, Inc. (Natick, MA). In this paper, the static friction models are studied through SIMULINK® by applying fixed and variable step sizes. The comparison shows that the static Karnopp model is not only numerically tractable but also can be inclusive of the fundamental friction characteristics of both stick-slip and correct friction predictions. Finally, this paper presents an improved Karnopp model for clutch modeling with the use of SIMULINK®, and the simulation shows that this model is computationally tractable with smooth dynamics.

scholarly journals A Nitsche-based formulation for fluid-structure interactions with contact

2020 ◽  
Vol 54 (2) ◽  
pp. 531-564
Author(s):  
Erik Burman ◽  
Miguel A. Fernández ◽  
Stefan Frei
Keyword(s):  
Contact Surface ◽  
Solid Mechanics ◽  
Contact Problems ◽  
Joint Interface ◽  
Fluid Structure Interactions ◽  
Contact Conditions ◽  
Fluid Structure ◽  
Interface Contact ◽  
Numer Anal ◽  
Fully Eulerian Approach

We derive a Nitsche-based formulation for fluid-structure interaction (FSI) problems with contact. The approach is based on the work of Chouly and Hild (SIAM J. Numer. Anal. 51 (2013) 1295–1307) for contact problems in solid mechanics. We present two numerical approaches, both of them formulating the FSI interface and the contact conditions simultaneously in equation form on a joint interface-contact surface Γ(t). The first approach uses a relaxation of the contact conditions to allow for a small mesh-dependent gap between solid and wall. The second alternative introduces an artificial fluid below the contact surface. The resulting systems of equations can be included in a consistent fashion within a monolithic variational formulation, which prevents the so-called “chattering” phenomenon. To deal with the topology changes in the fluid domain at the time of impact, we use a fully Eulerian approach for the FSI problem. We compare the effect of slip and no-slip interface conditions and study the performance of the method by means of numerical examples.

“Internal Variables” Effects in Punch Friction Characterization

1998 ◽  
Vol 120 (3) ◽  
pp. 510-516
Author(s):  
Tze-Chi Hsu ◽  
Chi-Chia Liu
Keyword(s):  
Metal Forming ◽  
Initial Boundary ◽  
Friction Model ◽  
Internal Variables ◽  
Friction Modeling ◽  
Lubrication Regimes ◽  
Mixed Regime ◽  
Constant Friction ◽  
Tensile Strip ◽  
Friction Models

Despite the complexity and importance of friction, most current simulations of metal-forming processes use relatively simple friction models such as the Amontons-Coulomb constant friction coefficient. It has been pointed out that simple models are not capable of capturing the influence of process variables such as geometry, speed, and surface topography on friction. A realistic friction model should include the internal variables such as lubricant film thickness, tooling roughness, and workpiece roughness. In the present research, the punch friction tests which use a tensile strip experiment to simulate the stretching of sheet over a punch corner radius in a typical draw die are used to measure the effects of internal variables on friction in various stretching conditions. The measured friction coefficients increase with lower stretching speed and decrease if lubricant is applied at the interface between workpiece and cylindrical pin. Theoretical friction modeling, which includes the different lubrication regimes range from thick film, thin film, mixed regime and boundary regime, are presented. Numerical methods have been used to solve the governing differential equations with the known initial boundary conditions obtained from the experiments. The theoretical prediction shows the same trend as the experimental measurements.

Sign in / Sign up

Export Citation Format

Share Document