Dry friction: influence of local dynamic aspect on contact pressure, kinematics and friction

2003 ◽  
pp. 545-552 ◽  
Author(s):  
V. Linck ◽  
L. Baillet ◽  
Y. Berthier
Keyword(s):  
Contact Pressure ◽  
Dry Friction ◽  
Local Dynamic ◽  
Dynamic Aspect

Experimental Modeling of Wear Behavior of Filled Elastomer SBR under Dry Friction-Influence of Roughness

2015 ◽  
Vol 640 ◽  
pp. 13-20
Author(s):  
Rachid Djeridi ◽  
Mohand Ould Ouali
Keyword(s):  
Weight Loss ◽  
Contact Pressure ◽  
Dry Friction ◽  
Sliding Friction ◽  
Operating Time ◽  
Wear Behaviour ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Filled Elastomer ◽  
Tribological Parameters

The wear behaviour of a filled styrene butadiene rubber (SBR) is investigated in this paper. The material contact used is plan /plan with a hard steel XC38. The influence of tribological parameters such as type contact (contact plan/plan under dry friction), relative motion between the contact surfaces (rotational disc/fixed elastomer sample), topography of the surface contact (roughness), loading (normal load or contact pressure), sliding friction and operating time or number of cycles is investigated. The highlighting of these parameters influence and analysis results permits us to formulate a wear model for the filled elastomer SBR. The model is based on the Archard law developed for metallic materials. The modification concerns the introduction of material parameters to take accounts the hyperelastic behaviour of elastomer due to the presence of amorphous phase. Particular interest is given to the influence of the surface state of the indenter given by the counterface arithmetic roughnessRaon the weight loss of the elastomer due to the wear phenomena. For a lower value (little to 6.3μm) of the arithmetic roughness, the weight loss is insignificant for different contact pressure and various sliding speeds. This effect is more noticeable at higher values of roughness and dependent on other tribological parameters. This results comfort other conclusion on the literature that express the influence of roughness by the geometric parameters of the micro-waves in the surface. The effects of the roughness can be explained by the ratio between the amplitude and wavelength of the corrugation. Indeed, we relate the roughness influence at the strain energy restored by material hyperelastic which also is, necessarily, a function of the velocity sliding and pressure contact.

Pressures on webs in wound rolls due to winding and contact

TAPPI Journal ◽  
2014 ◽  
Vol 13 (2) ◽  
pp. 41-50
Author(s):  
C. MOLLAMAHMUTOGLU ◽  
S. GANAPATHI ◽  
J.K. GOOD
Keyword(s):  
Contact Pressure ◽  
High Speed ◽  
Air Entrainment ◽  
Surface Velocity ◽  
Hydraulic Pressure ◽  
Local Dynamic ◽  
Compression Tests ◽  
Dead Weight ◽  
Wound Rolls ◽  
The Web

Paper, film, and metallic webs have designed surfaces. Process engineers design these surfaces to ensure they will coat or print correctly. In some cases, such as tissue, the manufactured surface is designed to provide softness. After the web is formed, care must be taken to maintain the web surface for the intended use or for subsequent processing. Web surfaces can be damaged by contact pressure, which is due to multiple sources. Tissues can suffer decreased loft and softness as a result of excessive pressure. Winding webs into rolls creates pressure on each web layer that varies with radial location. Almost all high speed winders must employ a nip roller in contact with the outer surface of the winding roll to prevent air entrainment. The nip roller, which may or may not be covered with an elastomer, induces local dynamic pressures where it contacts the winding roll that travel at the surface velocity of the winding roll. After rolls are wound, they can witness additional surface contact pressure. Often rolls are stored on flat surfaces and the dead weight of the roll induces contact pressure. In other cases, the roll may be moved by a clamp truck that employs hydraulic pressure to clamp and lift the wound roll. The objective of this paper is to demonstrate a method by which the total pressure in a web due to winding and to contact can be determined. Wound rolls of newsprint and polyester will be subjected to compression tests to verify the method.

A calculation method of surface wear of plastic line gear pair under dry friction conditions

2021 ◽  
pp. 1-29
Author(s):  
Yifan Lin ◽  
Yangzhi Chen ◽  
Ye Changkun ◽  
Yueling Lyu
Keyword(s):  
Contact Pressure ◽  
Calculation Method ◽  
Dry Friction ◽  
Operating Conditions ◽  
Ideal Condition ◽  
Influence Coefficient ◽  
Wear Depth ◽  
Gear Pair ◽  
Surface Wear ◽  
Actual Operating

Abstract Parallel line gear pair (PLGP) can achieve pure rolling meshing along its theoretical contact curves under the ideal condition. However, the actual meshing positions may deviate from the theoretical ones under the actual operating conditions, which may result in the alternation of contact pressure distribution and cause relative sliding of the meshing surfaces. Contact pressure and relative sliding are two main factors causing surface wear. A calculation method of surface wear of plastic line gear (LG) pair under dry friction conditions was studied theoretically and experimentally, taking a polyoxymethylene (POM) PLGP as an example. Based on the geometric model of PLGP considering the misalignments under the actual operating conditions, this method employs the three-element model and influence coefficient method to compute the contact pressure with the consideration of the viscoelasticity of the gear material. Archard's wear equation is applied to calculate the surface wear depth. Results of the wear experiment of the POM PLGP specimens validated the feasibility of the calculation method. This study provides a necessary basis for the engineering application of plastic LG pair.

scholarly journals Three-Dimensional Finite Element Analysis of Contact Problem in Dry Friction Clutches

Lubricants ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 115
Author(s):  
Laith A. Sabri ◽  
Nadica Stojanović ◽  
Adolfo Senatore ◽  
Muhsin Jaber Jweeg ◽  
Azher M. Abed ◽  
...  
Keyword(s):  
Finite Element ◽  
Contact Problem ◽  
Contact Pressure ◽  
Working Conditions ◽  
Dry Friction ◽  
Contact Stiffness ◽  
Intermediate Step ◽  
Element Analysis ◽  
Clutch System ◽  
Friction Clutch

We present an investigation through numerical analysis (FEM) of the solution of the contact problem in friction clutch systems during engagement manoeuver. The case of high contact pressure between the sliding elements of a clutch system (flywheel, friction clutch and pressure plate) has been also considered. A finite element model of a dry friction clutch system (single disc) to estimate the distributions of the contact pressure between the contact elements of the clutch system under different working conditions has been developed and the main findings are discussed. Furthermore, the effect of modules of elasticity (contact stiffness) on the distribution of contact pressure of the mating surfaces was investigated. Also, the results encompass the deformations of the contacting surfaces for different cases. This work could provide a fundamental intermediate step to obtain a partial solution to the thermos-elastic problem in order to compute the thermal-driven deformations and stresses in the automotive clutches and brakes under different working conditions.

Three-Dimensional Immunoelectron Microscopy of Yeast Cells by a New High-Resolution Replica Method

1985 ◽  
Vol 43 ◽  
pp. 562-563
Author(s):  
Hirano T. ◽  
M. Yamaguchi ◽  
M. Hayashi ◽  
Y. Sekiguchi ◽  
A. Tanaka
Keyword(s):  
High Resolution ◽  
Plasma Polymerization ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Replica Method ◽  
Yeast Cells ◽  
Dynamic Aspect ◽  
Replica Technique ◽  
Gaseous Hydrocarbon ◽  
Transmission Electron

A plasma polymerization film replica method is a new high resolution replica technique devised by Tanaka et al. in 1978. It has been developed for investigation of the three dimensional ultrastructure in biological or nonbiological specimens with the transmission electron microscope. This method is based on direct observation of the single-stage replica film, which was obtained by directly coating on the specimen surface. A plasma polymerization film was deposited by gaseous hydrocarbon monomer in a glow discharge.The present study further developed the freeze fracture method by means of a plasma polymerization film produces a three dimensional replica of chemically untreated cells and provides a clear evidence of fine structure of the yeast plasma membrane, especially the dynamic aspect of the structure of invagination (Figure 1).

Maximum Interlabial Pressures in Normal Speakers

1997 ◽  
Vol 40 (2) ◽  
pp. 400-404 ◽  
Author(s):  
Virginia A. Hinton ◽  
Winston M. C. Arokiasamy
Keyword(s):  
Speech Production ◽  
Contact Pressure ◽  
Direct Evidence ◽  
Unit Area ◽  
Jaw Movement ◽  
Contractile Forces ◽  
Contact Pressures ◽  
Muscle Contractile

It has been hypothesized that typical speech movements do not involve large muscular forces and that normal speakers use less than 20% of the maximum orofacial muscle contractile forces that are available (e.g., Amerman, 1993; Barlow & Abbs, 1984; Barlow & Netsell, 1986; DePaul & Brooks, 1993). However, no direct evidence for this hypothesis has been provided. This study investigated the percentage of maximum interlabial contact pressures (force per unit area) typically used during speech production. The primary conclusion of this study is that normal speakers typically use less than 20% of the available interlabial contact pressure, whether or not the jaw contributes to bilabial closure. Production of the phone [p] at conversational rate and intensity generated an average of 10.56% of maximum available interlabial pressure (MILP) when jaw movement was not restricted and 14.62% when jaw movement was eliminated.

Rim Slip and Bead Fitment of Tires: Analysis and Design2

2006 ◽  
Vol 34 (1) ◽  
pp. 38-63 ◽  
Author(s):  
C. Lee
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Frictional Torque ◽  
Finite Element Analyses ◽  
Inflation Pressure ◽  
Contact Pressure Distribution ◽  
Design Modification ◽  
Iterative Design ◽  
Slip Resistance ◽  
Braking Torque

Abstract A tire slips circumferentially on the rim when subjected to a driving or braking torque greater than the maximum tire-rim frictional torque. The balance of the tire-rim assembly achieved with weight attachment at certain circumferential locations in tire mounting is then lost, and vibration or adverse effects on handling may result when the tire is rolled. Bead fitment refers to the fit between a tire and its rim, and in particular, to whether a gap exists between the two. Rim slip resistance, or the maximum tire-rim frictional torque, is the integral of the product of contact pressure, friction coefficient, and the distance to the wheel center over the entire tire-rim interface. Analytical solutions and finite element analyses were used to study the dependence of the contact pressure distribution on tire design and operating attributes such as mold ring profile, bead bundle construction and diameter, and inflation pressure, etc. The tire-rim contact pressure distribution consists of two parts. The pressure on the ledge and the flange, respectively, comes primarily from tire-rim interference and inflation. Relative contributions of the two to the total rim slip resistance vary with tire types, depending on the magnitudes of ledge interference and inflation pressure. Based on the analyses, general guidelines are established for bead design modification to improve rim slip resistance and mountability, and to reduce the sensitivity to manufacturing variability. An iterative design and analysis procedure is also developed to improve bead fitment.

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