Investigation of Friction Using Non-Newtonian Lubricant Model in Hydrostatic Extrusion of Tungsten Alloy

2015 ◽  
Vol 813-814 ◽  
pp. 541-549
Author(s):  
Pankaj Tomar
Keyword(s):  
Extrusion Process ◽  
Friction Model ◽  
Hydrostatic Extrusion ◽  
Work Zone ◽  
Tungsten Alloy ◽  
Contact Friction ◽  
Hard Material ◽  
Lubricating Layer ◽  
Lubricant Viscosity

Friction at die/billet interface is a complex phenomenon affected by various operating and process parameters in metal forming industries. In presence of lubricating layer at the interfacial contact friction effect is reduced and enhances tool life and surface quality of product. The lubricant viscosity is strongly dependent on pressure and temperature during deformation of hard material and an accurate prediction of lubricants viscosity leads to realistic results in the work zone. Therefore, the paper incorporates numerical simulation of friction at the die/billet interface in hydrostatic extrusion of tungsten alloy 93W for three different lubricants whose rheology is represented by a Non-Newtonian friction model. The billet heating effect is incorporated in the investigation and results show that the co-efficient of friction varies in a range (0.058 to 0.062) along the work zone for various lubricating conditions in hydrostatic extrusion process.

A new friction model for the slide guide in elevator systems: Experimental and theoretical investigations

2008 ◽  
Vol 222 (11) ◽  
pp. 2177-2189 ◽  
Author(s):  
X G Zhang ◽  
K J Guo ◽  
H G Li ◽  
G Meng
Keyword(s):  
Time Lag ◽  
Friction Model ◽  
Dynamical Analysis ◽  
Contact Friction ◽  
Proposed Model ◽  
Theoretical Investigations ◽  
Friction Models ◽  
Design And Manufacture ◽  
Sliding Regimes

In the design and manufacture of elevator systems, the slide guide in elevators moves in contact against the guide rail. This kind of surface contact exhibits a highly non-linear hysteretic friction behaviour, which hampers the riding quality of the elevator systems to a great extent. First, this paper presents an experimental investigation on this type of phenomenon through the measurement of contact friction force between the interface of the slide guide and the rail under different combinations of input parameters. The experiment clearly shows various types of frictional behaviour, including presliding/gross-sliding regimes, the transition behaviour between them, friction overshoot, time lag, velocity (weakening and strengthening) dependence, etc. In addition, it is found that for different materials in contact, lubrication conditions and friction duration have strong impacts on the evaluation of their friction characteristics. Based on the observations of this test, an improved friction model derived from the Bouc—Wen model is then proposed and compared with other friction models. The Bouc—Wen model is improved by adding elements considering the velocity dependence and friction overshoot. The numerical simulations show that the proposed model can capture the behaviour found in the experiments, agrees with the experimental data reasonably well, and may be used for the dynamical analysis of the elevator systems.

Study on Lubrication Properties of Emulsion for Aluminum Cold-Rolling

2011 ◽  
Vol 228-229 ◽  
pp. 321-326 ◽  
Author(s):  
Wen Xia Wang ◽  
Ping Liu ◽  
Guo Qiang Yao
Keyword(s):  
Cold Rolling ◽  
Surface Quality ◽  
Contact Length ◽  
Friction Model ◽  
Rolling Speed ◽  
Work Zone ◽  
Lubrication Film ◽  
Rolled Aluminum ◽  
Emulsion Film

Paper discusses that water content of emulsion has effects on the surface quality of cold-rolled aluminum alloy 5052 and higher concentration of emulsion gave thicker lubrication film and better surface quality of aluminum strip. When the speed of rolling reaching a critical speed, thickness of emulsion film will decrease with time. Film forming of emulsion shows that when rolling speed is low, properties of emulsion is similar to that of oil, while when speed reaching a critical value, mechanism of lubrication in rolling work zone will change from plate-out model suitable for low rolling speed to starvation model suitable for high rolling speed .This paper also discusses friction model for cold-rolling, and explains that the contact length of work zone and strip and forward slip get greater with rolling reduction increasing , which easily result in lubrication failure in the work zone.

An improved nonlinear model considering relative velocity for the friction behavior between untwisted glass-fiber tow and roller

2021 ◽  
pp. 004051752110308
Author(s):  
Yang Liu ◽  
Zhong Xiang ◽  
Xiangqin Zhou ◽  
Zhenyu Wu ◽  
Xudong Hu
Keyword(s):  
Friction Coefficient ◽  
Glass Fiber ◽  
Relative Velocity ◽  
Friction Model ◽  
Woven Fabric ◽  
Test Results ◽  
Application Process ◽  
Friction Behavior ◽  
Improved Model

Friction between the tow and tool surface normally happens during the tow production, fabric weaving, and application process and has an important influence on the quality of the woven fabric. Based on this fact, this paper studied the influence of tension and relative velocity on the three kinds of untwisted-glass-fiber tow-on-roller friction with a Capstan-based test setup. Furthermore, an improved nonlinear friction model taking both tension and velocity into account was proposed. According to statistical test results, firstly, the friction coefficient was found to be positively correlated with tension and relative velocity. Secondly, tension and velocity were complementary on the tow-on-roller friction behavior, with neither being superior to the other. Thirdly, an improved model was found to present well the nonlinear characteristics between friction coefficient and tension and velocity, and predicational results of the model were found to agree well with the observations from Capstan tests.

Quantitative Study on the Effect of Extrusion Process of AZ80 Magnesium Alloy

2010 ◽  
Vol 129-131 ◽  
pp. 1191-1195
Author(s):  
Yan Lou
Keyword(s):  
Set Theory ◽  
Rough Set ◽  
Rough Set Theory ◽  
Extrusion Process ◽  
Average Weight ◽  
Characteristic Parameters ◽  
Billet Temperature ◽  
Az80 Magnesium Alloy ◽  
Ram Speed

By data mining from 3DFEM simulation and Rough Set Theory (RST), it was performed that the extrusion process and die structures effect on the quality of AZ80 magnesium extrudate. The weights of the effect can be obtained. The results show that the effect of the billet temperature on the product quality is dominate, and its average weight is 0.27. The second important parameter is the ram speed and its average weight is 0.22. In addition, it was also found that the effect of the die characteristic parameters on the extrudate is insignificant.

scholarly journals An Efficient Contact Model for the Simulation of Cargo Airdrop Extraction Phase

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Leiming Ning ◽  
Jichang Chen ◽  
Mingbo Tong
Keyword(s):  
Degrees Of Freedom ◽  
Friction Model ◽  
Rigid Bodies ◽  
Contact Dynamics ◽  
Moving Frame ◽  
Contact Friction ◽  
Practical Implementation ◽  
Contact Formulation ◽  
Efficient Code ◽  
Extraction Phase

A high-fidelity cargo airdrop simulation requires the accurate modeling of the contact dynamics between an aircraft and its cargo. This paper presents a general and efficient contact-friction model for the simulation of aircraft-cargo coupling dynamics during an airdrop extraction phase. The proposed approach has the same essence as the finite element node-to-segment contact formulation, which leads to a flexible, straightforward, and efficient code implementation. The formulation is developed under an arbitrary moving frame with both aircraft and cargo treated as general six degrees-of-freedom rigid bodies, thus eliminating the restrictions of lateral symmetric assumptions in most existing methods. Moreover, the aircraft-cargo coupling algorithm is discussed in detail, and some practical implementation details are presented. The accuracy and capability of the present method are demonstrated through four numerical examples with increasing complexity and fidelity.

Hydrostatic Extrusion With Controlled Follower Block Clearance

1975 ◽  
Vol 97 (1) ◽  
pp. 25-31 ◽  
Author(s):  
K. M. Kulkarni ◽  
J. A. Schey
Keyword(s):  
Ambient Temperature ◽  
Surface Finish ◽  
Extrusion Ratio ◽  
Hydrostatic Extrusion ◽  
Extrusion Force ◽  
Processing Conditions ◽  
Surface Processing ◽  
Specimen Diameter ◽  
Lubricant Viscosity ◽  
Breakthrough Pressure

Hydrostatic extrusion of annealed 1100 aluminum was investigated experimentally at ambient temperature. The principal variables studied were lubricant viscosity which was varied from less than 100 to over 76,000 SUS at 100 deg F and the diametral clearance between the follower block and the extrusion cylinder which ranged from 0.0005 to 0.0030 in. for the 1.026 in. dia. cylinder. The specimen diameter was 0.97 or 1.00 in. corresponding to an extrusion ratio of 4.75 or 5.00, respectively. The included die angle was either 60 deg or 90 deg. The results show that with a proper combination of the lubricant viscosity and the follower block clearance, hydrostatic extrusion can be accomplished without the necessity of any sealing of the container on the follower block side. The optimum clearance for minimum breakthrough pressure increases as the lubricant viscosity increases. The extrusion force increases with die angle. The paper discusses the various factors that affect the magnitude of the breakthrough pressure and the occasional uneven bamboo-type appearance of the surface. Processing conditions must be selected carefully since the lowest extrusion force does not necessarily lead to a product with the best surface finish.

Investigation of the Effects of Technological Parameters on Surface Roughness in Extrusion Bars of Aluminum Alloy

2019 ◽  
Vol 889 ◽  
pp. 155-160
Author(s):  
Trong Mai Nguyen ◽  
Đuc Quy Tran ◽  
Van Nghe Pham ◽  
Van Canh Nguyen
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Surface Quality ◽  
Research Work ◽  
Extrusion Process ◽  
Optimal Parameters ◽  
Technological Parameters

In this research work, the result of the effects of technological parameters on surface roughness in extrusion bars of aluminum alloy were pesented. The results of this study may be used for choosing optimal parameters of extrusion process so that surface quality of extruded bar was improved.

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