FE forming analysis with nonlinear friction coefficient model considering contact pressure, sliding velocity and sliding length

2016 ◽  
Vol 227 ◽  
pp. 161-168 ◽  
Author(s):  
Yoshikiyo Tamai ◽  
Toru Inazumi ◽  
Ken-ichi Manabe
Keyword(s):  
Friction Coefficient ◽  
Contact Pressure ◽  
Nonlinear Friction ◽  
Sliding Velocity ◽  
Forming Analysis

Experiment and simulation of friction coefficient of polyoxymethylene

2018 ◽  
Vol 70 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Xiaoshuang Xiong ◽  
Lin Hua ◽  
Xiaojin Wan ◽  
Can Yang ◽  
Chongyang Xie ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
Friction Force ◽  
Normal Load ◽  
Fe Model ◽  
Sliding Velocity ◽  
Experiment Data ◽  
Simulation Data ◽  
Content Type

Purpose The purposes of this paper include studying the friction coefficient of polyoxymethylene (POM) under a broad range of normal load and sliding velocity; developing a mathematical model of friction coefficient of POM under a broad range of normal loads and sliding velocities; and applying the model to dynamic finite element (FE) analysis of mechanical devices containing POM components. Design/methodology/approach Through pin-on-disc experiment, the friction coefficient of POM in different normal loads and sliding velocities is investigated; the average contact pressure is between 5 and 15 Mpa and the sliding velocity is from 0.05 to 0.9 m/s. A friction algorithm is developed and embedded in the FE model to simulate the friction of POM in different normal loads and sliding velocities. Findings The friction coefficient of POM against steel declines with the increase of normal loads when the contact pressure is between 5 and 15 Mpa. The friction coefficient of POM against steel increases markedly when the sliding velocity is between 0.05 and 0.15 m/s, it decreases sharply between 0.15-0.45 m/s and then it stabilizes at high sliding velocity between 0.45 and 0.9 m/s. The friction coefficient of POM in different working operations has a significant effect on contact stress and shear stress. The simulation data and experiment data of POM friction force fit very well; therefore, it can be concluded that the friction algorithm and FE model are accurate. Originality/value The friction coefficient of POM under a broad range of normal loads and sliding velocities is investigated. The friction coefficient model of POM is established as a function of normal loads and sliding velocities in the dry sliding condition. A friction algorithm is developed and embedded in the FE model of the friction of POM. The mathematical model of the friction coefficient accurately agrees with the experiment data, and simulation data and experiment data of the POM friction force fit very well.

scholarly journals The kinetic friction of saline ice against itself at low sliding velocities

1991 ◽  
Vol 15 ◽  
pp. 242-246 ◽  
Author(s):  
D. E. Jones ◽  
F. E. Kennedy ◽  
E. M. Schulson
Keyword(s):  
Experimental Investigation ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
Testing System ◽  
Kinetic Friction ◽  
Sliding Velocity ◽  
Sliding Interface ◽  
The Mean ◽  
Peak Value

An experimental investigation was performed on the kinetic friction coefficient of laboratory-grown, columnar saline ice sliding against itself. Tests were performed on a dual-opposing load apparatus specially manufactured for attachment to an MTS testing system. The mean kinetic friction coefficient, μ, was measured for sliding velocities from 10−6 to 5 × 10−2 m s−1 at temperatures from —3° to —40°C under a contact pressure of about 20 kPa. The ice specimens were oriented with grain columns perpendicular to the sliding interface. At -3°C and at —10°C, three distinct regions were observed: from 10−6 to about 10−5ms−1, μwas nearly constant at 0.5; at velocities from 10−5 to 10−3 m s−1, μ began to drop rapidly to about 0.1; and, above 10−3 m s−1, μ began to level off at ~0.05. The velocity at which μ began to decline increased with decreasing temperature. At temperatures below —10°C, μ increased from ~0.5 at v =10−6ms−1 to a peak value of ~0.7 near a velocity of 5 × 10−5ms−1 and then fell rapidly to about 0.1 at 10−2ms−1. In general, μ increased with decreasing temperature and sliding velocity.

scholarly journals Artificial Neural Networks Based Friction Law for Elastomeric Materials Applied in Finite Element Sliding Contact Simulations

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Aleksandra Serafińska ◽  
Wolfgang Graf ◽  
Michael Kaliske
Keyword(s):  
Neural Networks ◽  
Finite Element ◽  
Artificial Neural Networks ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
Momentum Balance ◽  
Sliding Velocity ◽  
Friction Law ◽  
Elastomeric Materials ◽  
Artificial Neural

A realistic characterization of the frictional behaviour of materials and mechanical systems is of prime importance for the assessment of their contact interaction properties, especially in the context of undesired temperature rise or intensive wear leading to service life reduction. A characteristic tribological property of elastomeric materials is the dependency of the friction coefficient on the local contact pressure, sliding velocity, and temperature in the contact interface. Thus, the friction coefficient is not constant in the entire contact area but varies according to the magnitudes of the aforementioned three influencing factors. In this contribution, a friction law based on artificial neural networks (ANN) is presented, which is able to capture the nonlinear dependencies of the friction coefficient on the contact pressure, sliding velocity, and temperature. Due to an extraordinary adaptivity of the ANN structure, these nonlinear relations stemming from experimental data can be modelled properly within the introduced friction law, in contrast to other friction formulations, which are limited by the fitting quality of their parameters. The ANN based friction law is implemented into a contact formulation of the finite element method (FEM). Especially, the linearization of contact contributions to the weak form of momentum balance equation, required for the FEM, is developed taking into account the differentiability of the ANN. The applicability of the developed friction law within the finite element analysis of tires as well as within sliding simulations of rubber elements is presented in this paper.

scholarly journals The kinetic friction of saline ice against itself at low sliding velocities

1991 ◽  
Vol 15 ◽  
pp. 242-246 ◽  
Author(s):  
D. E. Jones ◽  
F. E. Kennedy ◽  
E. M. Schulson
Keyword(s):  
Experimental Investigation ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
Testing System ◽  
Kinetic Friction ◽  
Sliding Velocity ◽  
Sliding Interface ◽  
The Mean ◽  
Peak Value

An experimental investigation was performed on the kinetic friction coefficient of laboratory-grown, columnar saline ice sliding against itself. Tests were performed on a dual-opposing load apparatus specially manufactured for attachment to an MTS testing system. The mean kinetic friction coefficient, μ, was measured for sliding velocities from 10−6 to 5 × 10−2 m s−1 at temperatures from —3° to —40°C under a contact pressure of about 20 kPa. The ice specimens were oriented with grain columns perpendicular to the sliding interface. At -3°C and at —10°C, three distinct regions were observed: from 10−6 to about 10−5ms−1, μwas nearly constant at 0.5; at velocities from 10−5 to 10−3 m s−1, μ began to drop rapidly to about 0.1; and, above 10−3 m s−1, μ began to level off at ~0.05. The velocity at which μ began to decline increased with decreasing temperature. At temperatures below —10°C, μ increased from ~0.5 at v =10−6ms−1 to a peak value of ~0.7 near a velocity of 5 × 10−5ms−1 and then fell rapidly to about 0.1 at 10−2ms−1. In general, μ increased with decreasing temperature and sliding velocity.

Influence of the contact with friction on the deformation behavior of advanced high strength steels in the Nakajima test

2021 ◽  
pp. 030932472110212
Author(s):  
Mohammad Mehdi Kasaei ◽  
Marta C Oliveira
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Rate ◽  
Contact Pressure ◽  
Deformation Behaviour ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced High Strength Steels ◽  
Deformation Mechanics ◽  
Nakajima Test

This work presents a new understanding on the deformation mechanics involved in the Nakajima test, which is commonly used to determine the forming limit curve of sheet metals, and is focused on the interaction between the friction conditions and the deformation behaviour of a dual phase steel. The methodology is based on the finite element analysis of the Nakajima test, considering different values of the classic Coulomb friction coefficient, including a pressure-dependent model. The validity of the finite element model is examined through a comparison with experimental data. The results show that friction affects the location and strain path of the necking point by changing the strain rate distribution in the specimen. The strain localization alters the contact status from slip to stick at a portion of the contact area from the pole to the necking zone. This leads to the sharp increase of the strain rate at the necking point, as the punch rises further. The influence of the pressure-dependent friction coefficient on the deformation behaviour is very small, due to the uniform distribution of the contact pressure in the Nakajima test. Moreover, the low contact pressure range attained cannot properly replicate real contact condition in sheet metal forming processes of advanced high strength steels.

Study of the Size Effects and Friction Conditions in Microextrusion—Part II: Size Effect in Dynamic Friction for Brass-Steel Pairs

2007 ◽  
Vol 129 (4) ◽  
pp. 677-689 ◽  
Author(s):  
Lapo F. Mori ◽  
Neil Krishnan ◽  
Jian Cao ◽  
Horacio D. Espinosa
Keyword(s):  
Grain Size ◽  
Friction Coefficient ◽  
Size Effect ◽  
Contact Pressure ◽  
Size Effects ◽  
Numerical Models ◽  
Kolsky Bar ◽  
Experimental Results ◽  
Material Response ◽  
Dynamic Coefficients

In this paper, the results of experiments conducted to investigate the friction coefficient existing at a brass-steel interface are presented. The research discussed here is the second of a two-part study on the size effects in friction conditions that exist during microextrusion. In the regime of dimensions of the order of a few hundred microns, these size effects tend to play a significant role in affecting the characteristics of microforming processes. Experimental results presented in the previous companion paper have already shown that the friction conditions obtained from comparisons of experimental results and numerical models show a size effect related to the overall dimensions of the extruded part, assuming material response is homogeneous. Another interesting observation was made when extrusion experiments were performed to produce submillimeter sized pins. It was noted that pins fabricated from large grain-size material (211μm) showed a tendency to curve, whereas those fabricated from billets having a small grain size (32μm), did not show this tendency. In order to further investigate these phenomena, it was necessary to segregate the individual influences of material response and interfacial behavior on the microextrusion process, and therefore, a series of frictional experiments was conducted using a stored-energy Kolsky bar. The advantage of the Kolsky bar method is that it provides a direct measurement of the existing interfacial conditions and does not depend on material deformation behavior like other methods to measure friction. The method also provides both static and dynamic coefficients of friction, and these values could prove relevant for microextrusion tests performed at high strain rates. Tests were conducted using brass samples of a small grain size (32μm) and a large grain size (211μm) at low contact pressure (22MPa) and high contact pressure (250MPa) to see whether there was any change in the friction conditions due to these parameters. Another parameter that was varied was the area of contact. Static and dynamic coefficients of friction are reported for all the cases. The main conclusion of these experiments was that the friction coefficient did not show any significant dependence on the material grain size, interface pressure, or area of contact.

Viscous Friction Effect During the Process of Tightening and Loosening of Bolted Joints

2021 ◽  
Author(s):  
Qingyuan Lin ◽  
Yong Zhao ◽  
Qingchao Sun ◽  
Kunyong Chen
Keyword(s):  
Friction Coefficient ◽  
Viscous Friction ◽  
Normal Pressure ◽  
Friction Model ◽  
Bolted Joints ◽  
Critical Parameters ◽  
Bolted Joint ◽  
Sliding Velocity ◽  
Friction Effect ◽  
Bearing Friction

Abstract Bolted connection is one of the most widely used mechanical connections because of its easiness of installation and disassembly. Research of bolted joints mainly focuses on two aspects: high precision tightening and improvement of anti-loosening performance. The under-head bearing friction coefficient and the thread friction coefficient are the two most important parameters that affect the tightening result of the bolted joint. They are also the most critical parameters that affect the anti-loosening performance of the bolted joint. Coulomb friction model is a commonly used model to describe under-head bearing friction and thread friction, which considers the friction coefficient as a constant independent of normal pressure and relative sliding velocity. In this paper, the viscous effect of the under-head bearing friction and thread friction is observed by measuring the friction coefficient of bolted joints. The value of the friction coefficient increases with the increase of the relative sliding velocity and the decrease of the normal pressure. It is found that the Coulomb viscous friction model can better describe the friction coefficient of bolted joints. Taking into account the dense friction effect, the loosening prediction model of bolted joints is modified. The experimental results show that the Coulomb viscous friction model can better describe the under-head bearing friction coefficient and thread friction coefficient. The model considering the dense effect can more accurately predict the loosening characteristics of bolted joints.

Desirability of Tribo-Performance of Natural Based Thermoset and Thermoplastic Composites: A Concise Review

2021 ◽  
Author(s):  
Aravind Dhandapani ◽  
Senthilkumar Krishnasamy ◽  
Thitinun Ungtrakul ◽  
Senthil Muthu Kumar Thiagamani ◽  
Rajini Nagarajan ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Relative Motion ◽  
Operating Temperature ◽  
Natural Fibers ◽  
Specific Wear Rate ◽  
Thermoplastic Composites ◽  
Sliding Velocity ◽  
Concise Review ◽  
Sliding Distance

Tribology, which may be defined as an interdisciplinary subject, deals with relative motion between two or more bodies, i.e., surfaces that are interacting relatively. Thus, tribology is a science covering three vital classes, namely, 1) wear, 2) friction, and 3) lubrication. The focus of this article is to bring out the elements that are influencing the wear-resisting behavior of thermosetting and thermoplastic composites with natural-based constituents. It was also identified from the literature sources that 1) the treatments on the natural fibers acting as reinforcement and 2) the addition of fillers in resin acting as matrix could improve the wear-resisting behavior of the composites. Additionally, other conditions such as 1) sliding speed, 2) sliding velocity, 3) sliding distance, and 4) operating temperature could also influence the friction coefficient and specific wear rate of the natural-based composites.

Sign in / Sign up

Export Citation Format

Share Document