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.

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.

“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.

scholarly journals Study on Friction in Automotive Shock Absorbers Part 1: Friction Simulation Using a Dynamic Friction Model in the Contact Zone of an FEM Model

Vehicles ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 212-232
Author(s):  
Ludwig Herzog ◽  
Klaus Augsburg
Keyword(s):  
Ride Comfort ◽  
Viscous Friction ◽  
Simulation Method ◽  
Friction Model ◽  
Model Parameters ◽  
Dynamic Friction ◽  
Friction Modeling ◽  
Shock Absorbers ◽  
Operation Conditions ◽  
Wide Range

The important change in the transition from partial to high automation is that a vehicle can drive autonomously, without active human involvement. This fact increases the current requirements regarding ride comfort and dictates new challenges for automotive shock absorbers. There exist two common types of automotive shock absorber with two friction types: The intended viscous friction dissipates the chassis vibrations, while the unwanted solid body friction is generated by the rubbing of the damper’s seals and guides during actuation. The latter so-called static friction impairs ride comfort and demands appropriate friction modeling for the control of adaptive or active suspension systems. In this article, a simulation approach is introduced to model damper friction based on the most friction-relevant parameters. Since damper friction is highly dependent on geometry, which can vary widely, three-dimensional (3D) structural FEM is used to determine the deformations of the damper parts resulting from mounting and varying operation conditions. In the respective contact zones, a dynamic friction model is applied and parameterized based on the single friction point measurements. Subsequent to the parameterization of the overall friction model with geometry data, operation conditions, material properties and friction model parameters, single friction point simulations are performed, analyzed and validated against single friction point measurements. It is shown that this simulation method allows for friction prediction with high accuracy. Consequently, its application enables a wide range of parameters relevant to damper friction to be investigated with significantly increased development efficiency.

Modeling of Piezo-Actuated Stick-Slip Micro-Drives: An Overview

2012 ◽  
Vol 81 ◽  
pp. 39-48 ◽  
Author(s):  
Ha Xuan Nguyen ◽  
Christoph Edeler ◽  
Sergej Fatikow
Keyword(s):  
Mechanical Model ◽  
Integrated Model ◽  
Friction Model ◽  
Fundamental Importance ◽  
Future Research ◽  
Stick Slip ◽  
Research Activities ◽  
Model Combining ◽  
Friction Models

This paper gives an overview about problems of modeling of piezo-actuated stick-slip micro-drives. It has been found that existing prototypes of such devices have been investigated empirically. There is only few research dealing with the theory behind this kind of drives. By analyzing the current research activities in this field, it is believed that the model of the drive depends strongly on the friction models, but in most cases neglecting any influences of the guilding system.These analyses are of fundamental importance for an integrated model combining friction model and mechanical model offering promising possibilities for future research.

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.

Comparison of Four Friction Models: Feature Prediction

2015 ◽  
Vol 11 (3) ◽  
Author(s):  
Yun-Hsiang Sun ◽  
Tao Chen ◽  
Christine Qiong Wu ◽  
Cyrus Shafai
Keyword(s):  
Numerical Model ◽  
Viscous Friction ◽  
Friction Model ◽  
Dynamic Features ◽  
Numerical Predictions ◽  
Wide Range ◽  
Model Predictions ◽  
Friction Models ◽  
Parameter Identifications ◽  
Model Structures

In this paper, we provide not only key knowledge for friction model selection among candidate models but also experimental friction features compared with numerical predictions reproduced by the candidate models. A motor-driven one-dimensional sliding block has been designed and fabricated in our lab to carry out a wide range of control tasks for the friction feature demonstrations and the parameter identifications of the candidate models. Besides the well-known static features such as break-away force and viscous friction, our setup experimentally demonstrates subtle dynamic features that characterize the physical behavior. The candidate models coupled with correct parameters experimentally obtained from our setup are taken to simulate the features of interest. The first part of this work briefly introduces the candidate friction models, the friction features of interest, and our experimental approach. The second part of this work is dedicated to the comparisons between the experimental features and the numerical model predictions. The discrepancies between the experimental features and the numerical model predictions help researchers to judge the accuracy of the models. The relation between the candidate model structures and their numerical friction feature predictions is investigated and discussed. A table that summarizes how to select the most optimal friction model among a variety of engineering applications is presented at the end of this paper. Such comprehensive comparisons have not been reported in previous literature.

A Comparison of Two Microslip Contact Models for Studying the Mechanics of Underplatform Dampers

2018 ◽  
Author(s):  
Chao Xu ◽  
Dongwu Li ◽  
Muzio M. Gola ◽  
Chiara Gastaldi
Keyword(s):  
Friction Coefficient ◽  
Friction Model ◽  
Tangential Displacement ◽  
Tangential Stiffness ◽  
Contact Loads ◽  
Contact Kinematics ◽  
Contact Models ◽  
Friction Models ◽  
Microslip Friction ◽  
Contact Parameters

In turbine blade systems, under-platform dampers are widely used to attenuate excessive resonant vibrations. Subjected to vibration excitation, the components with frictionally constrained interfaces can involve very complex contact kinematics induced by tangential and normal relative motions. To effectively calculate the dynamics of a blade-damper system, contact models which can accurately reproduce the interface normal and tangential motions are required. The large majority of works have been developed using macroslip friction models to model the friction damping at the contact interface. However, for those cases with small tangential displacement where high normal loads are applied, macroslip models are not enough to give accurate results. In this paper two recently published microslip models are compared, between them and against the simple macroslip spring-slider model. The aim is to find to which extent these models can accurately predict damper mechanics. One model is the so called GG array, where an array of macroslip elements is used. Each macroslip element of the GG array is assigned its own contact parameters and for each of them four parameters are needed: normal stiffness, tangential stiffness, normal gap and friction coefficient. The other one is a novel continuous microslip friction model. The model is based on a modification of the original classic IWAN model to couple normal and tangential contact loads. Like the GG array the model needs normal and tangential stiffness, and friction coefficient. Unlike the GG array the model is continuous and, instead of the normal gap required by the GG array, the Modified IWAN model needs a preload value. The two models are here applied to the study of the mechanics of a laboratory under-platform damper test rig. The results from the two models are compared and allow their difference, both for damper mechanics and for the complex-spring coefficients, to be assessed.

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.

scholarly journals Validation of Friction Model Parameters Identified Using the IHB Method Using Finite Element Method

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Abdallah Hadji ◽  
Njuki Mureithi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Friction Force ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Friction Model ◽  
Balance Method ◽  
Model Parameters ◽  
Friction Models ◽  
Element Method

A hybrid friction model was recently developed by Azizian and Mureithi (2013) to simulate the friction behavior of tube-support interaction. However, identification and validation of the model parameters remains unresolved. In previous work, the friction model parameters were identified using the reverse harmonic method, where the following quantities were indirectly obtained by measuring the vibration response of a beam: friction force, sliding speed of the force of impact, and local displacement at the contact point. In the present work, the numerical simulation by the finite element method (FEM) of a beam clamped at one end and simply supported with the consideration of friction effect at the other is conducted. This beam is used to validate the inverse harmonic balance method and the parameters of the friction models identified previously. Two static friction models (the Coulomb model and Stribeck model) are tested. The two models produce friction forces of the correct order of magnitude compared to the friction force calculated using the inverse harmonic balance method. However, the models cannot accurately reproduce the beam response; the Stribeck friction model is shown to give the response closest to experiments. The results demonstrate some of the challenges associated with accurate friction model parameter identification using the inverse harmonic balance method. The present work is an intermediate step toward identification of the hybrid friction model parameters and, longer-term, improved analysis of tube-support dynamic behavior under the influence of friction.

Hysteretic effects of dry friction: modelling and experimental studies

2007 ◽  
Vol 366 (1866) ◽  
pp. 747-765 ◽  
Author(s):  
Jerzy Wojewoda ◽  
Andrzej Stefański ◽  
Marian Wiercigroch ◽  
Tomasz Kapitaniak
Keyword(s):  
Numerical Simulations ◽  
Dry Friction ◽  
Experimental Studies ◽  
Friction Model ◽  
Hysteretic Effect ◽  
Motion Characteristic ◽  
Friction Models ◽  
Theoretical Analyses ◽  
Friction Modelling

In this paper, the phenomena of hysteretic behaviour of friction force observed during experiments are discussed. On the basis of experimental and theoretical analyses, we argue that such behaviour can be considered as a representation of the system dynamics. According to this approach, a classification of friction models, with respect to their sensitivity on the system motion characteristic, is introduced. General friction modelling of the phenomena accompanying dry friction and a simple yet effective approach to capture the hysteretic effect are proposed. Finally, the experimental results are compared with the numerical simulations for the proposed friction model.

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