Evolution of Sliding Contact Wear Between Deformable Conducting Bodies via a Multiphysics Framework

Author(s):  
John G. Michopoulos ◽  
Athanasios P. Iliopoulos ◽  
Nicole A. Apetre ◽  
John C. Steuben ◽  
Andrew J. Birnbaum

Abstract A multiphysics computational framework is introduced and exercised to predict the wear behavior of two deformable, heat-conducting bodies under conditions of sliding contact. This framework enables the solution of a coupled system of partial differential equations (PDEs) expressing the conservation of energy and momentum along with two ordinary differential equations (ODEs) expressing mass conservation. This system is intended to capture wear evolution for each of the bodies forming a wear pair, in a self-consistent manner. Furthermore, an arbitrary-Lagrangian-Eulerian approach has been integrated to enable tracking the evolution of the wear fronts on both elements of the sliding contact pair through physics-informed mesh deformation. A theorem and a corollary are proved to indicate that most existing models describing wear that are expressed in the form of an ODE are actually manifestations of the law of conservation of mass. The framework is applied for two distinct slider-base pairs. The first involves an aluminum alloy slider and a copper alloy base. The second pair is identical to the first except it contains a thin strip of soda-lime glass embedded in the surface of the base. The effects of this glass layer on the wear of all participating bodies in comparison to the pair that does not contain this layer are presented. They indicate that while the glass layer has a wear mitigation effect for the stationary base it slightly increases the wear of the slider when compared with the respective bodies when the glass is not present.

Author(s):  
John G. Michopoulos ◽  
Athanasios P. Iliopoulos ◽  
John C. Steuben ◽  
Andrew J. Birnbaum ◽  
Nicole A. Apetre

Abstract A recently developed multiphysics computational framework is exercised to predict the wear behavior of two deformable and heat conducting bodies under conditions of sliding contact. This framework enables the solution of a high dimensional thermo-mechanical problem simultaneously and tightly coupled with the associated wear evolution models for each of the wear pair bodies, thus enabling predictions of wear for both of them. Two distinct slider-base pairs are modeled. The first involves an aluminum alloy slider and a copper alloy base. The second is a pair identical to the first except it contains a thin strip of soda lime glass embedded in the surface of the base. The objective of this effort is to establish the effects of this glass layer on the wear of all participating bodies in comparison to the pair that does not contain this layer. The results indicate that while the glass layer has a wear mitigation effect for the stationary base it slightly increases the wear of the slider when compared with the respective bodies when the glass is not present.


Author(s):  
John G. Michopoulos ◽  
Athanasios P. Iliopoulos ◽  
John C. Steuben ◽  
Andrew J. Birnbaum

An approach exploiting the relevant conservation laws associated with the wear due to sliding between deformable heat conducting bodies is presented in this work. The proposed methodology considers a pair of wearing objects in contact where their wear behaviors are encapsulated by semantically reduced one-dimensional, time-dependent ordinary differential equations (ODEs) as a replacement to the full mass conservation PDEs governing mass loss due to the various mechanisms present at the interface. At the same time, the conservation of energy and momentum are still expressed by the full form of the PDEs representing them. To assess the feasibility of this approach a reciprocating sliding contact pair of dissimilar materials is considered. The high dimensional thermo-mechanical problem is solved simultaneously and tightly coupled with the two ODE wear models for each of the wear pair bodies, thus enabling predictions of wear for both of them. Furthermore, an Arbitrary-Lagrangian-Eulerian (ALE) approach has been used to produce the evolution of the wear fronts on both elements of the sliding contact pair through physics-informed mesh deformation consistent with the results computed in the previous step. The main advantage of this approach enables the usage of any low dimensional wear model (i.e, mechanical failure, phase transformation-based, etc.) in a computationally detailed and efficient manner.


2014 ◽  
Vol 214 ◽  
pp. 106-112 ◽  
Author(s):  
Adam Krzysztof Pilat

This elaboration presents a dynamic model of an Active Magnetic Bearing (AMB) developed in COMSOL Multiphysics. The electromagnetic field is calculated on the basis of Partial Differential Equations (PDEs). The calculated electromagnetic force is applied to the rotor, which is free to move. The Arbitrary Lagrangian-Eulerian (ALE) method for mesh deformation is applied to achieve rotor motion on the bearing plane. The planar rotor motion is described by a set of Ordinary Differential Equations (ODEs) solved in parallel to the electromagnetic field calculations. To enable rotor levitation, three local PD controllers are applied. The mathematical formulas of the control action are coded in the form of COMSOL equations and embedded into the rotor motion ODEs.


2010 ◽  
Vol 146-147 ◽  
pp. 825-828
Author(s):  
Yong Wang ◽  
Yong Hong Xu ◽  
Gang Yao Kuang ◽  
Ying Zhang

In this paper, continuous running test was conducted using the disk drive spindle micromotors used in automobiles DVD. The commutator and brush were made of AuAg/AgCuNiCe/Cu and AgPd/CuNiSn layered composite respectively. In order to investigate the wear behavior of the commutator, the micromotors were dissected after ran continuously for different time. The worn surface of the commutator and the brush were characterized using an SEM equipped with EDS. Also, the cross section of the commutator was analyzed. It was shown that the AuAg layer was not totally worn off until 1500 h of running test. AuAg transferred from the commutator to the brush. It was interesting that Au was found on the silver layer where the depth of wear crater surpassed the thickness of the original AuAg layer. Small particles enriched in Cu, Ni and Ce were observed on the contact surface of AgCuNiCe layer, which was thought to improve the wear resistance of the commutator. The wear mechanism was mainly slight abrasion whereas no effect of arc was found on the sliding contact area.


2014 ◽  
Vol 569 ◽  
pp. 70-75 ◽  
Author(s):  
Cinta Lorenzo-Martin ◽  
Oyelayo O. Ajayi ◽  
Sol Torrel ◽  
Iqbal Shareef ◽  
George R. Fenske

1998 ◽  
Vol 38 (12) ◽  
pp. 1946-1958 ◽  
Author(s):  
M. Rao ◽  
C. J. Hooke ◽  
S. N. Kukureka ◽  
P. Liao ◽  
Y. K. Chen

Proper lubrication and surface modification are key factors to improve the tribological behavior of interacting sliding surfaces under lubricated conditions. Surface texturing of interacting surfaces has found to be an emerging technique that modifies the surfaces deterministically by producing surface features in the form of surface asperities or grooves with specific shape, size and distribution. The present paper address the impact of positive surface textures (protrusions) and number of positive textures in the sliding direction on friction and wear behavior of parallel sliding contacts. The square shaped positive surface textures are created on the specimen by ink-jet followed by chemical etching process. The sliding experiments are conducted on pin on disc friction and wear test rig by providing different sliding conditions such as plain dry, plain with lubricant and textures with lubricant between the interacting surfaces. The results indicated that the textures with lubricated condition exhibit lower friction and wear compared to other two conditions. Furthermore, it is reported that among the tested samples, the textured sample with number of textures three in sliding direction has shown a prominent effect in reducing friction and wear of parallel sliding contact.


Author(s):  
Bhuvnesh Sharma ◽  
Sunil Kumar ◽  
Carlo Cattani ◽  
Dumitru Baleanu

Abstract A rigorous analysis of coupled nonlinear equations for third-grade viscoelastic power-law non-Newtonian fluid is presented. Initially, the governing partial differential equations for conservation of energy and momentum are transformed to nonlinear coupled ordinary differential equations using exact similarity transformations which are known as Cattaneo–Christov heat flux model for third-grade power-law fluid. The homotopy analysis method (HAM) is utilized to approximate the systematic solutions more precisely with shear-thickening, moderately shear-thinning, and most shear-thinning fluids. The solution depends on various parameters including Prandtl number, power index, and temperature variation coefficient. A systematic analysis of boundary-layer flow demonstrates the impact of these parameters on the velocity and temperature profiles.


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