Modeling Wear of Journal Bearings · bearings (JB) (fig. 1) as a representative of large-area...
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Modeling Wear of Journal Bearings P. Bergmann 1 , F. Grün 1 1. Montanuniversität Leoben, Department Product Engineering, Franz-Josef-Straße 18, Leoben, A-8700 Introduction: Hydrodynamic Journal bearings (JB) (fig. 1) as a representative of large-area tribological contacts in internal combustion engines face increased demands in regard to life expectancy and reliability. Actual developments (e.g. start- stop technology and downsizing) push JB to operation points (mixed friction) with increased wear resulting in the necessity of numerical wear evaluation. Computational Methods: Mixed friction is characterized by the coexistence of hydrodynamic pressure, solved by Reynolds’ equation (1), and solid contact pressure, taken into account by a load- displacement function according to [1]. The wear equation (2) based on Archard’s wear law is incorporated as an ordinary differen- tial equation [2]. The surrounding structure is the core part of a close-to-component test rig demanding equation (3) to take elastic deformation into account, fig. 2. Results: The conducted time depend- ent wear investigation yields a wear induced change in force equilibrium (fig. 3,a) and the according evolution of wear pattern (fig. 3,b). Conclusions: The developed numeric- al methodology in COMSOL allows the calculation of progressive wear locally and chronologically resolved for arbi- trary large area contacts based on em- pirically determined wear constants C. References: 1. Greenwood, J.A., Wiliamson, J.B.P, Contact of Nominally Flat Surfaces, Proceedings of the royal society, 295, 300- 319 2. Elabbasi, N., Simulating Wear in Disc Brakes, COMSOL Conference 2014 Boston Figure 2. Model of test rig part under external load in mixed friction operation (hyd. and solid pressure) Figure 1. Principle sketch of a hydrodynamic journal bearing ( ) ( ) 0 = ⋅ ∇ + ∂ ∂ av t hv h t ρ ρ (1) v C p t h w ⋅ ⋅ = ∂ ∂ (2) V F S u t u + ⋅ ∇ = ∂ ∂ 2 2 ρ (3) a) b) Figure 3. a) run of force equilibrium and wear, b) chronologically and locally resolved evolution of wear Excerpt from the Proceedings of the 2016 COMSOL Conference in Munich
Transcript of Modeling Wear of Journal Bearings · bearings (JB) (fig. 1) as a representative of large-area...
Modeling Wear of Journal BearingsP. Bergmann1, F. Grün1
1. Montanuniversität Leoben, Department Product Engineering, Franz-Josef-Straße 18, Leoben, A-8700
Introduction: Hydrodynamic Journalbearings (JB) (fig. 1) as a representative oflarge-area tribological contacts in internalcombustion engines face increaseddemands in regard to life expectancy andreliability. Actual developments (e.g. start-stop technology and downsizing) push JB tooperation points (mixed friction) withincreased wear resulting in the necessity ofnumerical wear evaluation.
Computational Methods: Mixed friction ischaracterized by the coexistence ofhydrodynamic pressure, solved byReynolds’ equation (1), and solid contactpressure, taken into account by a load-displacement function according to [1]. Thewear equation (2) based on Archard’s wearlaw is incorporated as an ordinary differen-tial equation [2]. The surrounding structureis the core part of a close-to-component testrig demanding equation (3) to take elasticdeformation into account, fig. 2.
Results: The conducted time depend-ent wear investigation yields a wearinduced change in force equilibrium(fig. 3,a) and the according evolution ofwear pattern (fig. 3,b).
Conclusions: The developed numeric-al methodology in COMSOL allows thecalculation of progressive wear locallyand chronologically resolved for arbi-trary large area contacts based on em-pirically determined wear constants C.References:1. Greenwood, J.A., Wiliamson, J.B.P,
Contact of Nominally Flat Surfaces, Proceedings of the royal society, 295, 300-319
2. Elabbasi, N., Simulating Wear in Disc Brakes, COMSOL Conference 2014 Boston
Figure 2. Model of test rig part under external load in mixed friction operation (hyd. and solid pressure)
Figure 1. Principle sketch of a hydrodynamic journal bearing
( ) ( ) 0=⋅∇+∂∂
avt hvht
ρρ (1)
vCpt
hw ⋅⋅=∂∂
(2)
VFSutu
+⋅∇=∂∂
2
2
ρ (3)
a)
b)
Figure 3. a) run of force equilibrium and wear, b) chronologically and locally resolved evolution of wear
Excerpt from the Proceedings of the 2016 COMSOL Conference in Munich
