A Finite Element Study of Flat Rolling

1988 ◽  
Vol 110 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Yhu-Jen Hwu ◽  
J. G. Lenard
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Model Comparison ◽  
Element Solution ◽  
Eulerian Formulation ◽  
The Coefficient Of Friction ◽  
Flat Rolling ◽  
Roll Deformation ◽  
Roll Gap ◽  
Element Study

Using an Eulerian formulation, a finite element solution for the flat rolling problem is presented. Calculations are performed to establish the effects of roll deformation and of the variation of the coefficient of friction in the roll gap on the predictive capabilities of the model. Comparison to the data of Al-Salehi et al. (1973) and Shida and Awazuhara (1973) indicates that the differences between measurements and calculations decrease when the above-mentioned effects are accounted for.

The Difficulties of Predicting the Coefficient of Friction in Cold Flat Rolling

2021 ◽  
Vol 143 (10) ◽  
Author(s):  
Máté Szűcs ◽  
György Krallics ◽  
John G. Lenard
Keyword(s):  
Cold Rolling ◽  
Coefficient Of Friction ◽  
Rolling Process ◽  
Technical Literature ◽  
Steel Strips ◽  
The Coefficient Of Friction ◽  
Flat Rolling ◽  
Frictional Forces ◽  
Predictive Relations ◽  
Roll Gap

Abstract The flat rolling process is initiated when the frictional forces draw the strip to be rolled into the roll gap. These forces depend on the coefficient of friction, knowledge of which is essential to understand, describe, and analyze the process. Several predictive formulae for the coefficient have been presented in the technical literature. Contradictions are observed, however, when their predictions are compared to each other. The data obtained while cold rolling aluminum and steel strips are used in the analyses. A model of the rolling process—accounting for strain hardening, frictional events, and varying speeds—is then used to determine the coefficients of friction. The use of statistical analyses is found to yield more reliable results than the use of the predictive relations.

Simulating Torsional Slip in V-Band Clamp Joints

2015 ◽  
Vol 798 ◽  
pp. 53-58
Author(s):  
Salahaddin M. Sahboun ◽  
Simon M. Barrans
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Load Capacity ◽  
Contact Region ◽  
Finite Element Technique ◽  
Torsional Load ◽  
V Band ◽  
The Coefficient Of Friction ◽  
Element Technique

In this paper a finite element technique to predict the torsional load capacity of V-band clamp joints is presented. The development of this complex, multi-step analysis is explained and the results compared with alternate theories which ignore or take account of transverse friction in the band to flange contact region. It is shown that accounting for transverse friction yields a better comparison with the finite element results for lower coefficients of friction whilst ignoring this component gives better results for higher coefficients of friction. Torsional load capacity is shown to increase with band diameter and T-bolt tension but to be less dependent on the coefficient of friction.

A New Model for the Prediction of Roll Deformation in a 20-High Sendzimir Mill

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
J. H. Cho ◽  
S. M. Hwang
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
New Model ◽  
Roll Profile ◽  
Strip Shape ◽  
Element Simulation ◽  
Strip Profile ◽  
Flat Rolling ◽  
Sendzimir Mill ◽  
Roll Deformation

A sound model for the prediction of the deformed roll profile during flat rolling is vital for the precision control of the strip profile and strip shape. However, preliminary investigations reveal that the applicability of existing models may be limited due to their inherent predictions errors. In this paper, a new model is proposed which is capable of precisely predicting the deformed roll profile in a multihigh mill. The model, which is developed on the basis of the predictions from finite element simulation, is applied to the analysis of roll deformation in a 20-high Sendzimir mill under some special conditions, such as rigid outer rolls and no roll shifting, etc. The prediction accuracy of the new model is demonstrated through comparison with the predictions from the finite element simulation.

Deformation Characteristics of Ultra-Fine Grained Al6061 Chip in Machining by Finite Element Method

2010 ◽  
Vol 44-47 ◽  
pp. 2931-2934
Author(s):  
Chun Ling Wu ◽  
Bang Yan Ye
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Coefficient Of Friction ◽  
Metal Cutting ◽  
High Hardness ◽  
Rake Angle ◽  
Fine Grained ◽  
The Coefficient Of Friction ◽  
Cutting Velocity ◽  
Element Method

Ultra-fine grained chips with higher hardness and strength than bulk can be produced by severe plastic deformation during orthogonal metal cutting. A finite element method was developed to characterize the distribution of stress, strain, strain rate and temperature in the deformation area at different rake angles and cutting velocities. The coefficient of friction in the tool-chip interface is approximately obtained according model of mean coefficient of friction which is based on experiments in any machining conditions. The formation mechanics of ultra-fine grained chip is discussed and effect of rake angle on microstructure of chips is highlighted. The results of experiment and modeling have shown that chip materials with ultra-fine grained and high hardness can be produced with more negative tool rake angle at some lower cutting velocity.

scholarly journals A Contact Characteristic of Roller Bearing with Palm Oil-based Grease Lubrication

2021 ◽  
Vol 89 (2) ◽  
pp. 139-149
Author(s):  
Yap Jun Heng ◽  
Nurul Farhana Mohd Yusof ◽  
Lee Ann Yen ◽  
Shazlina Abd Hamid ◽  
Nurul Nadzirah Mohd Yusof
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Palm Oil ◽  
Frictional Contact ◽  
Roller Bearing ◽  
Rolling Contact ◽  
Von Mises Stress ◽  
The Coefficient Of Friction ◽  
Contact Characteristic ◽  
Von Mises

Grease lubricants are widely used in rolling contact applications to reduce friction between two rolling surfaces. Improper lubrication may cause high contact stress and deformation to the bearings and lead to machine failure The purpose of this study is to investigate the coefficient of friction produced by newly developed palm oil-based grease and to investigate the contact characteristics in lubricated roller bearings. In this work, the coefficient of friction of new greases was evaluated experimentally and the values were compared with the conventional mineral oil-based grease to investigate the friction performance. The friction test was performed using a four-ball tester. The finite element model was developed based on the roller bearing geometry and the simulation was carried out the evaluate the contact characteristic. The experimental result shows that the palm oil grease formulation A had the least coefficient of friction, followed by palm oil grease formulation B, mineral grease and food grade grease. This indicates that palm oil-based grease has the potential to be applied in rolling contact applications due to low friction characteristics. Finite element analysis shows that the maximum von Mises stress and total deformation for frictional contact are higher than the frictionless contact. For the frictional contact analysis with various lubricant COF, similar values were obtained with von Mises stress at 400.69 MPa and 3.4033×10-4 mm deformation. The finding shows that the small difference in grease COF did not affect the rolling contact. The finding also shows that the newly developed biodegradable grease has a similar performance in terms of rolling contact friction and contact characteristic in a condition that the bearing is operating in normal condition.

Finite element analysis of fretting wear considering variable coefficient of friction

2018 ◽  
Vol 233 (5) ◽  
pp. 758-768 ◽  
Author(s):  
Ling Li ◽  
Le Kang ◽  
Shiyun Ma ◽  
Zhiqiang Li ◽  
Xiaoguang Ruan ◽  
...  
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Variable Coefficient ◽  
Friction Model ◽  
Slip Condition ◽  
Fretting Wear ◽  
Partial Slip ◽  
Wear Volume ◽  
The Coefficient Of Friction ◽  
Contact Surfaces

Fretting wear is a kind of material damage in contact surfaces caused by microrelative displacement between two bodies. It can change the profile of contact surfaces, resulting in loosening of fasteners or fatigue cracks. Finite element method is an effective method to simulate the evolution of fretting wear process. In most studies of fretting wear, the coefficient of friction was assumed to be constant to simplify model and reduce the difficulty of solving. However, fretting wear test showed that the coefficient of friction was a variable related to the number of fretting cycles. Therefore, this paper introduces the coefficient of friction as a function of the number of fretting cycles in numerical simulation. A wear model considering variable coefficient of friction is established by combining energy consumption model and adaptive grid technique. The nodes of contact surfaces are updated through the UMESHMOTION subroutine. The effects of constant coefficient of friction and variable coefficient of friction on fretting wear are analyzed by comparing the wear amount under different loading conditions. The results show that when compared with coefficient of friction model, fretting wear is obviously affected by variable coefficient of friction and the variable coefficient of friction model has a larger wear volume when the fretting is in partial slip condition and mixed slip condition. In gross slip condition, the difference of wear volume between variable coefficient of friction model and coefficient of friction model decreases with the increase in the displacement amplitudes.

scholarly journals Finite Element Analysis of Ball Burnishing on Ball-End Milled Surfaces Considering Their Original Topology and Residual Stress

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 638 ◽  
Author(s):  
Cyrus Amini ◽  
Ramón Jerez-Mesa ◽  
J. Antonio Travieso-Rodriguez ◽  
Jordi Llumà ◽  
Aida Estevez-Urra
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Coefficient Of Friction ◽  
Surface Integrity ◽  
Finite Element Models ◽  
Real Surface ◽  
Ball Burnishing ◽  
Surface Geometry ◽  
Topological Features ◽  
The Coefficient Of Friction

Ball burnishing is a superfinishing operation whose objective is the enhancement of surface integrity of previously machined surfaces, hence its appropriateness to complement chip removal processes at the end of a production line. As a complex process involving plastic deformation, friction and three-dimensional interaction between solids, numerical solutions and finite element models have typically included a considerable amount of simplifications that represent the process partially. The aim of this paper is to develop a 3D numerical finite element model of the ball burnishing process including in the target workpiece real surface integrity descriptors resulting from a ball-end milled AISI 1038 surface. Specifically, its periodical topological features are used to generate the surface geometry and the residual stress tensor measured on a real workpiece is embedded in the target surface. Secondly, different models varying the effect of the coefficient of friction and the direction of application of burnishing passes with regards to the original milling direction are calculated. Results show that the resulting topology and residual stresses are independent of the burnishing direction. However, it is evident that the model outputs are highly influenced by the value of the coefficient of friction. A value of 0.15 should be implemented in order to obtain representative results through finite element models.

Asymptotic Stress Fields for Complete Contact Between Dissimilar Materials

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Kisik Hong ◽  
M. D. Thouless ◽  
Wei Lu ◽  
J. R. Barber
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Dissimilar Materials ◽  
The Other ◽  
Stress Fields ◽  
Finite Element Models ◽  
Local Stresses ◽  
The Coefficient Of Friction ◽  
Complete Contact ◽  
Insight Into

We investigate the influence of material dissimilarity on the traction fields at the corners of a contact between an elastic right-angle wedge and an elastic half-plane. The local asymptotic fields are characterized in terms of the properties of the leading eigenvalue for cases of slip and stick as a function of the Dundurs bimaterial parameters α and β, and the coefficient of friction f. Permissible values of α and β are partitioned into two possible ranges, one where behavior is qualitatively similar to the case where the indenting wedge is rigid [α = 1] and the other where behavior is similar to the case where the materials are the same [α = β = 0]. The results give insight into the high local stresses at the edge of a contact between elastically dissimilar bodies and can also be used to evaluate the effectiveness of mesh refinement in corresponding finite element models.

A Methodology for the Simulation of Surface-Contact Grinding Tool Topography

2009 ◽  
Vol 416 ◽  
pp. 519-523
Author(s):  
Guo Zhi Zhang ◽  
Xian Hua Zhang ◽  
Li Li Liu ◽  
Zeng Ju Wei
Keyword(s):  
Finite Element ◽  
Theoretical Model ◽  
Finite Element Model ◽  
Coefficient Of Friction ◽  
Surface Friction ◽  
Static Friction ◽  
Element Model ◽  
Friction Mechanism ◽  
Manufacturing Quality ◽  
The Coefficient Of Friction

Study on the effect of the surface manufacturing quality (roughness) to the friction between the surfaces. Based on the plastic theory of mechanism-based strain gradient (MSG) of the micro-plastic-mechanics and the contact theory, the theoretical model of the coefficient of friction between the rough surfaces and the non-linear finite element model between the grinding samples were established. Moreover, the surface stress distribution and the coefficient of friction were obtained through the sub-structure finite element method. The established model of static friction theoretical model and the accuracy of the finite element model were verified through comparing with the result of the static friction experiments between the grinding samples with different surface manufacturing quality. The study in the paper is important to the study on the surface friction mechanism.

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