The Effect of Crankshaft Flexibility on the EHL of Connecting Rod Bearings

Mian, Omar Y.; Merritt, David; Wang, Ducai

doi:10.4271/2002-01-0295

Cited by 8 publications

(5 citation statements)

References 1 publication

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“…The latter requires the input of the elastic compliances of both the housing-bearing assembly and the journal [7]. Hence, the housing deformations are estimated during the process and, together with the oil film pressure, are later transferred to the FE stress analysis of just the bearing to assess its behaviour under service conditions.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, the bearing shape and clearances between the bearing and housing surfaces are estimated. Using the finite difference in-house code SABRE-EHL [6,7], it is possible to estimate the hydro-dynamic oil film pressure and housing deformation during a complete engine cycle. At the same time, different indicators related to strength, wear, cavitation erosion and fretting are generated to assess the propensity for damage.…”

Section: Introductionmentioning

confidence: 99%

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Plain bearing stresses due to forming and oil film pressure

Burke-Veliz

Wang

Wahdy

et al. 2009

J. Phys.: Conf. Ser.

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Abstract. This paper describes a methodology for assessing critical stress ranges arising in automotive plain bearings during engine operations. An industry-produced and run simulation program provides information on oil film pressure and overall bearing deformation during accelerated performance tests. This code performs an elasto-hydrodynamic lubrication analysis accounting for the compliance of the housing and journal. Finite element analyses of a multilayer bearing are performed to assess the conditions responsible for possible fatigue damage over the bearing lining. The residual stresses arising from the forming and fitting process are first assessed. The stress analyses over the engine cycle show the intensity and distribution of cyclic tensile and compressive stresses in the bearing. The location of maximum stress range is found to be consistent with the damage observed in accelerated fatigue tests. Critical zones are identified in the lining for possible fatigue crack initiation and growth studies.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Plain bearing stresses due to forming and oil film pressure

Burke-Veliz

Wang

Wahdy

et al. 2009

J. Phys.: Conf. Ser.

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“…The input to the bearing stress analysis was provided by an industry-developed and run EHL software [16], which solves the Reynolds equation by the finite difference method and accounts for the elastic deformation of both journal and bearing-rod assembly. This EHL analysis assumes the absence of bubble collapse within the fluid and may also involve thermal responses, that is, include a heat balance analysis to determine the oil viscosity and material expansion in order to estimate with greater accuracy the clearances between bearing and journal.…”

Section: Elasto-hydrodynamic Lubricationmentioning

confidence: 99%

“…The bearing geometry and material properties were different from those considered for the accelerated fatigue test. The same industrial software [16] provided the oil film pressure and housing deformation arising under EHL conditions. In agreement with experimental evidence, the top shell was found to be subjected to higher specific load and therefore more prone to damage.…”

Section: Engine Conditionsmentioning

confidence: 99%

Residual and cyclic stresses in automotive plain bearings

Syngellakis¹,

Burke-Veliz²

2012

WIT Transactions on Engineering Sciences

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This paper presents a review of existing methodologies for predicting stress and strain development in automotive plain bearings. Initially, it deals with the modelling of the forming and fitting operations, leading to the determination of residual stresses, then with the numerical processes of generating cyclic stresses and plastic strains due to the reciprocating engine forces. Modelling tools as well as their adopted assumptions and simplifications are explained. Particular attention is given to the distinction between and effects of hydrodynamic and elastohydrodynamic lubrication conditions. The output of such analyses is illustrated through the inclusion of some typical results; its significance is discussed in the context of bearing design against fatigue failure.

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“…5,6 All significant stiffness and deformation effects, which can modify the bearing operating clearance are modelled. These include housing and crankshaft stiffness; 7 conrod distributed mass inertia effects; 8 journal misalignments due to crankshaft bending under gas and inertia loads, plus static fitting distortions due to bolt loads, interference and thermal expansion. 9 The programme has been developed in stages, with the aim of including all important characteristics required to accurately model the physical bearing system, giving a predictive tool for bearing design and problem diagnostics.…”

Section: Introductionmentioning

confidence: 99%

Contact and wear thermo-elastohydrodynamic model validation for engine bearings

Kalogiannis

Merritt

Mian

2017

Proceedings of the Institution of Mechanical Engineers, Part J:

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Tribological machine components such as engine crankshaft bearings operating at high load or rotational speeds often experience very thin oil films leading to asperity contact between the bearing and crankshaft. When the oil film thickness drops below the peak asperity height there is an increase in contact, wear and asperity power loss leading to worsening severity factors and seizure risk. Key factors influencing the bearing lubrication performance are the surface characteristics of the materials at the contact interface. SABRE-TEHL is a software simulation tool used for performing thermo-elastohydrodynamic analysis of bearing applications. In this current study, the development of a combined contact and wear model is demonstrated. This includes a hard contact model giving a direct surface contact pressure in areas of zero oil film thickness, a surface yield model with yield limits and plastic gradient from measured stress–strain data, an asperity wear model using measured surface roughness data and an asperity contact model based on measured roughness, asperity density and tip radius. Input surface roughness data are measured using a white light interferometry method. The effects of surface characterization in terms of roughness and stiffness properties are demonstrated using simulation results comparing an aluminium bimetal bearing with a polymer coated bearing, showing a significant reduction in asperity friction for the bearing with a polymer coating. Simulation results are compared with experimental test results for a 1.5 l diesel engine, a 2.0 l diesel engine and for a bearing fatigue test rig. Generally good agreement is seen when comparing the wear contours and wear depth on the bearing surface.

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The Effect of Crankshaft Flexibility on the EHL of Connecting Rod Bearings

Cited by 8 publications

References 1 publication

Plain bearing stresses due to forming and oil film pressure

Plain bearing stresses due to forming and oil film pressure

Residual and cyclic stresses in automotive plain bearings

Contact and wear thermo-elastohydrodynamic model validation for engine bearings

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