Three-dimensional thermohydrodynamic investigation on the micro-groove textures in the main bearing of internal combustion engine for tribological performances

Author(s):  
Anvar Ahmadkhah ◽  
Amir Hassan Kakaee

A three-dimensional thermohydrodynamic numerical simulation study was used to investigate the impact of the micro-groove surface texturing on the tribological performances in the main bearing of the internal combustion engine. For this purpose, various number of grooves and groove height to the bearing surface were applied to determine the optimal texture surface parameters by comparing the load-carrying capacity and friction force in the engine main bearing. In the multiphysics numerical model, the three-dimensional Navier–Stokes equation was employed considering the cavitation mechanism based on the Elrod method in the solution. Using the transverse grooves on the bearing surface altered the cavitation response and film reformation. To validate the use of the current numerical model for analyzing the bearings, the obtained results were compared with those of the published theoretical papers, where a good agreement was obtained. The bearing performance was studied in thermal interface conditions to find the optimal set textures parameters that gave minimum fiction force with minimum loss in load-carrying capacity. The bearing with the optimal micro-groove texture parameter showed a reduction in friction (around 16%) with the minimum reduction in load-carrying capacity (around 6%) and the maximum reduction of the flow work (around 15%) compared with the untextured bearing surface. This paper focuses on the thermohydrodynamic investigation with a combination of thermal effects of the fluid film in the textured bearing. Meanwhile, the heat transfer characteristic, temperature distribution of solid bodies, and convection heat transfer coefficient in the contact surfaces of the textured bearing were investigated. The proposed multiphysics numerical model can be widely used for predicting the optimal texture surface parameters in different engineering systems modeling. Moreover, using the three-dimensional-based numerical model is more cost-effective compared with the experimental evaluation of the textured surface.

2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.


2013 ◽  
Vol 690-693 ◽  
pp. 1999-2002
Author(s):  
Fan Ming Meng ◽  
Tao Yang ◽  
Tao Long

The influence of dimples on the inner surface of big end bearing in internal combustion engine (ICE) on tribological performances of the bearing was investigated based on Navier-Strokes equation and other associated equations. In doing so, the CFD modulus in the software ANSYS12 version is used to analyze the dimple effect on the tribological performances of the bearing using two-way fluid-solid coupling algorithm. Some mechanisms are revealed about the dimple effect on the load-carrying capacity and friction coefficient of oil film, and the deformation and stress for the textured big end bearing.


2011 ◽  
Vol 133 (4) ◽  
Author(s):  
C. I. Papadopoulos ◽  
E. E. Efstathiou ◽  
P. G. Nikolakopoulos ◽  
L. Kaiktsis

This paper presents an optimization study of the geometry of three-dimensional micro-thrust bearings in a wide range of convergence ratios. The optimization goal is the maximization of the bearing load carrying capacity. The bearings are modeled as micro-channels, consisting of a smooth moving wall (rotor), and a stationary wall (stator) with partial periodic rectangular texturing. The flow field is calculated from the numerical solution of the Navier-Stokes equations for incompressible isothermal flow; processing of the results yields the bearing load capacity and friction coefficient. The geometry of the textured channel is defined parametrically for several width-to-length ratios. Optimal texturing geometries are obtained by utilizing an optimization tool based on genetic algorithms, which is coupled to the CFD code. Here, the design variables define the bearing geometry and convergence ratio. To minimize the computational cost, a multi-objective approach is proposed, consisting in the simultaneous maximization of the load carrying capacity and minimization of the bearing convergence ratio. The optimal solutions, identified based on the concept of Pareto dominance, are equivalent to those of single-objective optimization problems for different convergence ratio values. The present results demonstrate that the characteristics of the optimal texturing patterns depend strongly on both the convergence ratio and the width-to-length ratio. Further, the optimal load carrying capacity increases at increasing convergence ratio, up to an optimal value, identified by the optimization procedure. Finally, proper surface texturing provides substantial load carrying capacity even for parallel or slightly diverging bearings. Based on the present results, we propose simple formulas for the design of textured micro-thrust bearings.


2015 ◽  
Vol 719-720 ◽  
pp. 202-205
Author(s):  
Cleirton A.S. Freitas ◽  
Mucio M.S. Nobrega ◽  
Édipo A. Bezerra ◽  
Otávio R.O. Cavalcante

Space trusses are three-dimensional structures made of steel bars very frequently used at the roof construction. The bars, with tubular section, are linking in the 3D form by connections. There are several types of connections to attach these members. The most economical connection is the staking end-flattened connection, also called typical node. The reduced cost and the fast assemblage of the truss are among their advantages. However, such connections present disadvantages like eccentricities and stiffness weakening of the tubular members. This research presents suggestions of reinforcement and constructive correction in the connection in order to increase its capacity. The base for this is the reduction of the eccentricity in typical node applying the spacer. This spacer was made by polymer composite with sisal fiber. In this work was developed experimental lab tests in prototypes with fifty four meters square of area. The results show an increase of 26% for collapse in the truss load carrying capacity when the suggested changes proposed in this article are used for the staking end-flattened connections.


Fire Research ◽  
2016 ◽  
Author(s):  
Abdelkadir Fellouh ◽  
Nourredine Benlakehal ◽  
Paulo Piloto ◽  
Ana Ramos ◽  
Luís Mesquita

Partially encased columns have significant fire resistance in comparison with steel bare columns. However, it is not possible to assess the fire resistance of such members simply by considering the temperature of the steel. The presence of concrete increases the mass and thermal inertia of the member and the variation of temperature within the cross section, in both the steel and concrete components. The annex G of EN1994-1-2:20051 allows to calculate the load carrying capacity of partially encased columns, for a specific fire rating time, considering the balanced summation model. New formulas will be proposed to calculate the plastic resistance to axial compression and the effective flexural stiffness. These two parameters are used to determine the buckling resistance. The finite element method is used to compare the results for the elastic critical load and the load carrying capacity of partially encased columns for different fire ratings of 30 and 60 min. This work compares the results from both solution methods, provides the validation of the three-dimensional model and demonstrates that a new design curve should be used for the buckling analysis of partially encased columns.


2017 ◽  
Vol 69 (4) ◽  
pp. 574-584 ◽  
Author(s):  
Anil B. Shinde ◽  
Prashant M. Pawar

Purpose This study aims to improve the performance of hydrodynamic journal bearings through partial grooving on the bearing surface. Design/methodology/approach Bearing performance analysis is numerically carried out using the thin film flow physics of COMSOL Multiphysics 5.0 software. Initially, the static performance analysis is carried out for hydrodynamic journal bearing system with smooth surface, and the results of the same are validated with results from the literature. In the later part of the paper, the partial rectangular shape micro-textures are modeled on bearing surface. The effects of partial groove pattern on the bearing performance parameters, namely, fluid film pressure, load carrying capacity, frictional power loss and frictional torque, are studied in detail. Findings The numerical results show that the values of maximum fluid film pressure, load carrying capacity, frictional power loss and frictional torque are considerably improved due to deterministic micro-textures. Bearing surface with partial groove along 90°-180° region results in 81.9 per cent improvement in maximum fluid film pressure and 75.9 per cent improvement in load carrying capacity as compared with smooth surface of journal bearing, with no increase in frictional power loss and frictional torque. Maximum decrease in frictional power loss and frictional torque is observed for partially grooving along 90°-360° region. The simulations are supported by proof-of-concept experimentation. Originality/value This study is useful in the appropriate selection of groove parameters on bearing surface to the bearing performance characteristics.


Author(s):  
Jagdish Keshav Khade

The vehicles on road are increasing with rapid rate which is good by transportation perspective and hence the growing need of oil-based fuel making transportation costly as the price of oil based fuel rising too. The quantity of oil-based fuel remains unchecked and the exhaust from oil-based fuel brings environmental problems like ‘‘green house effect’’, health issues for the operating environment. The electric vehicles is a good option for moving away with problems related to the oil-based fuel lot of researches is going on in world and money is being spent on the development of the electric vehicles. The problem related with electric vehicles are electric vehicles have low speed, having low load carrying capacity, and batteries having short life. The main aim of this research paper is to give an idea about fabrication of simple, cost effective electric motorcycle which can be done by replacing internal combustion engine and other components with brush less direct current gear motor, controller and lithium-ion battery. This electric motorcycle uses 48V 750w brushless direct current gear motor to propel the vehicle, lithium-ion battery as power source the brushless direct current motor. The 48v 750w brushless direct current gear motor have high load carrying capacity with acceptable speed and lithium-ion battery have more life than other batteries available in market such as lead acid battery. The lithium-ion battery has less weight, quick charge property, required less storage space compare to other batteries available in market.


2020 ◽  
Vol 23 (13) ◽  
pp. 2813-2821
Author(s):  
Peter Hyman ◽  
Adelaja Israel Osofero

The behaviour of axially loaded prestressed stayed columns is a commonly studied area. Despite the fact that load eccentricity in columns is commonplace in practice, the amount of investigation into these systems under eccentric loading is limited. This study employed finite element analysis to investigate the interactive post-buckling behaviour of prestressed stayed columns. Critical imperfection combination with respect to the load carrying capacity was established and a comparison of a planar and a three-dimensional model was carried out to investigate key differences in the models. In this work, it has been shown that the load carrying capacity of eccentrically loaded columns can be significantly reduced when buckling in interactive mode is observed. Furthermore, it was established that increase in eccentricity results in a decrease in load carrying capacity of columns for both planar and three-dimensional models. However, a major difference between the models is the twisting effect exhibited in the three-dimensional model under out-of-plane eccentric loading. This work highlights the importance of carefully designing prestressed stayed columns’ connections to minimise loading eccentricity as it has been shown that the benefit of employing these systems over unstayed columns reduces with increasing load eccentricity.


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