Multi-body dynamics: Historical evolution and application

The paper presents a mixed thermo-hydrodynamic analysis of elliptic bore bearings using combined solution of Navier-Stokes, continuity and energy equations for multi-phase flow conditions. A vapour transport equation is also included to ensure continuity of flow in the cavitation region for the multiple phases as well as Rayleigh-Plesset to take into account the growth and collapse of cavitation bubbles. This approach removes the need to impose artificial outlet boundary conditions in the form of various cavitation algorithms which are often employed to deal with lubricant film rupture and reformation. The predictions show closer conformance to experimental measurements than have hitherto been reported in the literature. The validated model is then used for the prediction of frictional power losses in big end bearings of modern engines under realistic urban driving conditions. In particular, the effect of cylinder deactivation (CDA) upon engine bearing efficiency is studied. It is shown that bigend bearings losses contribute to an increase in the brake specific fuel consumption with application of CDA contrary to the gains made in fuel pumping losses to the cylinders. The study concludes that implications arising from application of new technologies such as CDA should also include their effect on tribological performance.

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“…1). The localised deflection of the Babbitt overlay, D is obtained using the column method contact mechanics approach [29], where:…”

Section: Big End Bearing Geometrymentioning

confidence: 99%

Big End Bearing Losses with Thermal Cavitation Flow Under Cylinder Deactivation

et al. 2015

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“…Some engine bearings are furnished with soft overlays to encourage elastohydrodynamic regime of lubrication through localized deformation of the bearing bushing. In such cases, an iterative procedure is required [16].…”

Section: Main Journal Bearing Reactionsmentioning

confidence: 99%

Elasto-multi-body dynamics of internal combustion engines with tribological conjunctions

Perera

Theodossiades

Rahnejat

2010

Proceedings of the Institution of Mechanical Engineers, Part K:

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Reduction of frictional losses and NVH (Noise, Vibration, and Harshness) refinement constitute the key customer-focussed aims in internal combustion engine development. Numerical predictive tools have progressively become an important part of achieving these aims. However, the interactions and sometimes the conflicting requirements of the aforementioned objectives call for the inclusion of many phenomena in realistic models of practical significance. These phenomena occur at varying physics of scale, from micro-scale tribological conjunctions to small scale vibrations and onto large scale inertial dynamics. At the same time, the inclusion of many disciplines for a cohesive analysis will be required, such as rigid body dynamics and elastodynamics, as well as tribology. While the inclusion of such a multi-disciplinary approach is deemed essential, the use of analytical rather than numerical models, as far as possible, would render realistic predictions within the usual tight industrial timescales. This article presents an experimentally validated model of the engine piston assembly, which is based on the multiphysics, multi-scale nature of the interacting components. Furthermore, it provides predictions of some current development trends in engines such as the high output power to weight ratio and offset crankshaft. The emphasis of this article is on the integration of the kinetic reactions arising from the tribological conjunction of the dynamics of engine subsystems, piston, and crankshaft.

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“…Progress in manipulator modelling can be seen with the increase in modelling complexities from the late 1980s to present date. History of multibody dynamics has been presented by Rahnejat [46] and Schiehlen [47]. Computational dynamics has made rapid progress in the 20 th century.…”

Section: History Of Dynamic Modellingmentioning

confidence: 99%

A review of friction models in interacting joints for durability design

2017

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This paper presents a comprehensive review of friction modelling to provide an understanding of design for durability within interacting systems. Friction is a complex phenomenon and occurs at the interface of two components in relative motion. Over the last several decades, the effects of friction and its modelling techniques have been of significant interests in terms of industrial applications. There is however a need to develop a unified mathematical model for friction to inform design for durability within the context of varying operational conditions. Classical dynamic mechanisms model for the design of control systems has not incorporated friction phenomena due to non-linearity behaviour. Therefore, the tribological performance concurrently with the joint dynamics of a manipulator joint applied in hazardous environments needs to be fully analysed. Previously the dynamics and impact models used in mechanical joints with clearance have also been examined. The inclusion of reliability and durability during the design phase is very important for manipulators which are deployed in harsh environmental and operational conditions. The revolute joint is susceptible to failures such as in heavy manipulators these revolute joints can be represented by lubricated conformal sliding surfaces. The presence of pollutants such as debris and corrosive constituents has the potential to alter the contacting surfaces, would in turn affect the performance of revolute joints, and puts both reliability and durability of the systems at greater risks of failure. Key literature is identified and a review on the latest developments of the science of friction modelling is presented here. This review is based on a large volume of knowledge. Gaps in the relevant field have been identified to capitalise on for future developments. Therefore, this review will bring significant benefits to researchers, academics and industry professionals.

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Multi-body dynamics: Historical evolution and application

Cited by 85 publications

References 63 publications

Big End Bearing Losses with Thermal Cavitation Flow Under Cylinder Deactivation

Big End Bearing Losses with Thermal Cavitation Flow Under Cylinder Deactivation

Elasto-multi-body dynamics of internal combustion engines with tribological conjunctions

A review of friction models in interacting joints for durability design

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