Study on Logarithmic Crowning of Tapered Roller Profile Considering Angular Misalignment

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Zhenghai Wu ◽  
Yingqiang Xu ◽  
Kaian Liu
Keyword(s):  
Concentration Effect ◽  
Contact Pair ◽  
Angular Misalignment ◽  
Finite Line Contact ◽  
Finite Line ◽  
Tapered Roller ◽  
Profile Design ◽  
Roller Profile ◽  
Stress Concentration Effect ◽  
Contact Field

Abstract The angular misalignment of the tapered roller contact pair aggravates the stress edge effect and the stress concentration effect at the contact field, which in turn would affect bearing capacity and fatigue life of the contact pair. In this paper, based on the angular misalignment, the geometric interference model of the tapered roller contact pair was established. And two types of logarithmic crowning models for the roller profile design were theoretically deduced, in which design redundancy was considered through the quadratic processing of the pre-pressure. Then, with the discrete convolution and fast Fourier transform (DC-FFT) method and the conjugate gradient method (CGM), contact characteristics of the tapered roller with these two logarithmic profiles were verified. The results show that two profiles can effectively prevent the stress edge/concentration effect, improve contact pressure distribution and stress field of the roller in misalignment state, and ensure that the contact condition in alignment state is not greatly affected. The logarithmic crowning scheme is also suitable for the profile design of heavy-duty tapered rollers and can provide a reference for the crowning of other finite-line contact pairs under angular misalignment.

Enhancing weak magnetic field MME coupling in NdFeB magnet/piezoelectric composite cantilevers with stress concentration effect

2021 ◽  
Vol 118 (13) ◽  
pp. 132902
Author(s):  
Zhonghui Yu ◽  
Zhaoqiang Chu ◽  
Jikun Yang ◽  
Mohammad Javad Pourhosseini Asl ◽  
Zhanmiao Li ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Stress Concentration ◽  
Weak Magnetic Field ◽  
Concentration Effect ◽  
Piezoelectric Composite ◽  
Ndfeb Magnet ◽  
Stress Concentration Effect

A thermal EHL investigation for size effect of finite line contact on bush-pin hinge pairs in industrial chains

2020 ◽  
Vol 72 (5) ◽  
pp. 695-701
Author(s):  
Mingyu Zhang ◽  
Jing Wang ◽  
Peiran Yang ◽  
Zhaohua Shang ◽  
Yi Liu ◽  
...  
Keyword(s):  
Film Thickness ◽  
Peer Review ◽  
Contact Zone ◽  
Line Contact ◽  
Equivalent Radius ◽  
Content Type ◽  
Oil Film ◽  
Finite Line Contact ◽  
Finite Line ◽  
Thermal Ehl

Purpose This paper aims to study the influence of the dimension change of bush-pin on the pressure, oil film thickness, temperature rise and traction coefficient in contact zone by using a thermal elastohydrodynamic lubrication (EHL) model for finite line contact. Concretely, the effects of the equivalent curvature radius of the bush and the pin, and the length of the bush are investigated. Design/methodology/approach In this paper, the contact between the bush and pin is simplified as finite line contact. The lubrication state is studied by numerical simulation using steady-state line contact thermal EHL. A constitutive equation Ree–Eyring fluid is used in the calculations. Findings It is found that by selecting an optimal equivalent radius of curvature and prolonging the bush length can improve the lubrication state effectively. Originality/value Under specific working conditions, there exists an optimal equivalent radius to maximize the minimum oil film thickness in the contact zone. The increase of generatrix length will weaken the stress concentration effect in the rounded corner area at both ends of the bush, which can improve the wear resistance of chain. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0448.

Theoretical Modeling of Steel Strip Reinforced Flexible Pipe With Swaging End Fitting by Taking Into Account Stress Concentration Effect

2019 ◽  
Author(s):  
Yifan Gao ◽  
Wei Chen ◽  
Yong Bai
Keyword(s):  
Stress Concentration ◽  
Internal Pressure ◽  
Steel Strip ◽  
Displacement Discontinuity ◽  
Concentration Effect ◽  
Elastic Model ◽  
Thin Wall ◽  
Burst Strength ◽  
Joint Area ◽  
Stress Concentration Effect

Abstract A new theoretical model was proposed to calculate the burst pressure of steel strip reinforced flexible composite pipes (steel strip PSP) based on the thin wall cylindrical shell theory and the squeeze pressure expression between layers was derived. The radial displacement discontinuity of pipe wall in pipe-end fitting joint area takes in account in this model which could result in Stress Concentration Effect (SCE) in reinforcement layers. The SCE is caused by swaging end fitting clamped tightly at the end of the pipe. The result of the hoop strain in the joint area calculated by this model is greater than the one calculated by the classic elastic model, which leads to relative conservative burst strength of the pipe. The hoop stress variation via internal pressure on innermost reinforcement layer is introduced to predict the burst strength of the pipe. As the stress in the joint area reaches its ultimate strength, the strain on the same layer in the point far away from this area (x→∞) is extracted and the corresponding internal pressure is obtained as the burst strength of the pipe. The calculated data from two models were compared with the experiment results and the proposed new model showed better accuracy than the classic elastic model. Final additional parametric studies were conducted, while the effect of the pipe diameter, the winding angle, the number and thickness of the reinforcement layer on the burst strength of the pipe were studied. Useful conclusions were drawn for the design and application of the steel strip PSP in offshore engineering.

A thermal EHL investigation on plate-pin hinge pairs in silent chains using a narrow finite line contact

2020 ◽  
Vol 72 (10) ◽  
pp. 1139-1145
Author(s):  
Mingyu Zhang ◽  
Jing Wang ◽  
Jinlei Cui ◽  
Peiran Yang
Keyword(s):  
Film Thickness ◽  
Temperature Rise ◽  
Elastohydrodynamic Lubrication ◽  
Radius Of Curvature ◽  
Line Contact ◽  
Equivalent Radius ◽  
Content Type ◽  
Finite Line Contact ◽  
Pressure Peak ◽  
Finite Line

Purpose The purpose of this paper is to numerically study the variations of oil film pressure, thickness and temperature rise in the contact zone of plate-pin pair in silent chains. Design/methodology/approach A steady-state thermal elastohydrodynamic lubrication (EHL) model is built using a Ree–Eyring fluid. The contact between the plate and the pin is simplified as a narrow finite line contact, and the lubrication state is examined by varying the geometry and the plate speed. Findings With increase in the equivalent radius of curvature, the pressure peak and the central film thickness increase. Because the plate is very thin, the temperature rise can be neglected. Even when the influence of the rounded corner region is less, a proper design can beneficially increase the minimum film thickness at both edges of the plate. Under a low entraining speed, strong stress concentration results in close-zero film thickness at both edges of the plate. Originality/value This study reveals the EHL feature of the narrow finite line contact in plate-pin pairs for silent chains and will support the future works considering transient effect, surface features and wear.

scholarly journals A full numerical solution to the coupled cam–roller and roller–pin contact in heavily loaded cam–roller follower mechanisms

2017 ◽  
Vol 232 (10) ◽  
pp. 1273-1284 ◽  
Author(s):  
Shivam S Alakhramsing ◽  
Matthijn B de Rooij ◽  
Dirk J Schipper ◽  
Mark van Drogen
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Friction Model ◽  
Line Contact ◽  
Transient Effects ◽  
Power Losses ◽  
Lubricated Contacts ◽  
Finite Line Contact ◽  
Finite Line ◽  
Lubrication Characteristics ◽  
Lubrication Conditions

In cam–roller follower units two lubricated contacts may be distinguished, namely the cam–roller contact and roller–pin contact. The former is a nonconformal contact while the latter is conformal contact. In an earlier work a detailed transient finite line contact elastohydrodynamic lubrication model for the cam–roller contact was developed. In this work a detailed transient elastohydrodynamic lubrication model for the roller–pin contact is developed and coupled to the earlier developed cam–roller contact elastohydrodynamic lubrication model via a roller friction model. For the transient analysis a heavily loaded cam–roller follower unit is analyzed. It is shown that likewise the cam–roller contact, the roller–pin contact also inhibits typical finite line contact elastohydrodynamic lubrication characteristics at high loads. The importance of including elastic deformation for analyzing lubrication conditions in the roller–pin contact is highlighted here, as it significantly enhances the film thickness and friction coefficient. Other main findings are that for heavily loaded cam–roller follower units, as studied in this work, transient effects and roller slippage are negligible, and the roller–pin contact is associated with the highest power losses. Finally, due to the nontypical elastohydrodynamic lubrication characteristics of both cam–roller and roller–pin contact numerical analysis becomes inevitable for the evaluation of the film thicknesses, power losses, and maximum pressures.

Experimental investigation on new low cycle fatigue precision cropping process

2014 ◽  
Vol 229 (8) ◽  
pp. 1470-1476 ◽  
Author(s):  
Renfeng Zhao ◽  
Shengdun Zhao ◽  
Bin Zhong ◽  
Yong Tang
Keyword(s):  
Stress Concentration ◽  
Cross Sections ◽  
Low Cycle Fatigue ◽  
Fatigue Loading ◽  
High Energy ◽  
Concentration Effect ◽  
Cycle Fatigue ◽  
Stable Crack Propagation ◽  
New Type ◽  
Stress Concentration Effect

The traditional cropping processes have some disadvantages, such as poor surface quality, low yield, the waste of materials, and high energy consumption. The low cycle fatigue precision cropping process with circumferential loading, which is a new type of precision cropping process, is studied. According to the stress concentration effect of the V-shape notch, the fatigue crack on the tip of the V-shape notch is prompted to initiate and extend. The working principle of the precision cropping machine is described. The criterion that whether the crack on the root of the V-shape notch is initiated or not is provided under the effect of low cycle fatigue loading. The materials which are 0.2%C steel, H59 copper, 0.45%C steel, 20Cr steel, and LY12 aluminum are tested under two control curves. The initiation and propagation of crack are accelerated and the good cross sections of the metal bar are obtained. The results show that the mean stress of the metal bar in the cropping process can be effectively reduced due to the stress concentration effect of the V-shape notch. The metal bar’s stable crack propagation and fracture can be obtained when constantly increasing striking displacement and reducing the striking frequency in the cropping process at the same time in the process.

Fatigue life of tapered roller bearing subject to angular misalignment

2015 ◽  
Vol 230 (2) ◽  
pp. 147-158 ◽  
Author(s):  
Van-Canh Tong ◽  
Seong-Wook Hong
Keyword(s):  
Fatigue Life ◽  
Substantial Reduction ◽  
Roller Bearing ◽  
Loading Conditions ◽  
Angular Misalignment ◽  
Tapered Roller Bearing ◽  
Tapered Roller ◽  
Life Analysis ◽  
Tapered Roller Bearings ◽  
Fatigue Life Analysis

Angular misalignment, defined as the tilted angle between the outer ring and inner ring, is unavoidable in most applications of tapered roller bearings (TBRs) due to many potential causes such as shaft deflection, initial mounting error, bearing geometry inaccuracy, etc. The occurrence of TRB misalignment introduces considerable changes into the contact load and the pressure between rolling elements and the raceways and, thus, greatly influences the bearing life. However, few research results are available on the effects of angular misalignment in TRBs. This paper presents the fatigue life analysis for TRBs with consideration for angular misalignment effects. To this end, a mathematical TRB model is developed to provide a comprehensive fatigue life analysis for TRBs subjected to angular misalignment. The presented model is verified by comparing the estimated fatigue lives under several loading conditions with those from a reference program. Then, the effects of angular misalignment on the fatigue life of TRBs are evaluated systematically. The simulation results show the importance of TRB alignment for the investigated TRB by demonstrating that small amount of angular misalignment leads to a substantial reduction in the fatigue life of the TRB regardless of loading conditions. The results address the necessity of misalignment effects analysis for TRBs.

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