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Article
Publication date: 8 May 2018

Runlin Chen, Jianlei Wang, XiaoYang Yuan, Longlong Li and Yahui Cui

To meet the high stiffness requirement of bearings used in high-precision spindles, this paper aims to propose a novel kind of bearing composited by hydrostatic cavities and…

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Abstract

Purpose

To meet the high stiffness requirement of bearings used in high-precision spindles, this paper aims to propose a novel kind of bearing composited by hydrostatic cavities and tilting pads with preload.

Design/methodology/approach

Cavities are cut on the oil seal surface of a hybrid bearing, in which the tilting pads are set up. The load of the bearing is carried by the hydrostatic cavities and tilting pads. The structural features of this compound bearing and the controlling variables of the main stiffness coefficient are presented. Two basic design principles are proposed on the basis of equal machining clearance (EMC) and equal installation clearance (EIC).

Findings

The theoretical analysis indicates that the stiffness of compound bearings under the EMC condition increases to infinity monotonously when the preload coefficient of the tilting pad tends to 1, while the stiffness under the EIC condition has a peak value. Therefore, a synthetic design principle is proposed by synthetically using the above-mentioned two principles. The applicable range of the three principles is discussed through an example.

Originality/value

The study about technological combination of hydrostatic cavity and tilting pad in this paper can provide suggestions for the design of a high-stiffness bearing in a precision spindle.

Details

Industrial Lubrication and Tribology, vol. 70 no. 4
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 3 October 2017

Guihua Li and Longlong Wu

The purposes of this paper are to understand the user information seeking (IS) process under a new service system, to explore how users construct strategies and to identify the…

486

Abstract

Purpose

The purposes of this paper are to understand the user information seeking (IS) process under a new service system, to explore how users construct strategies and to identify the influences of the new service system on the IS process and behaviour.

Design/methodology/approach

A quality research study design that included questionnaires survey, observation, thinking-aloud and interviews was employed. In all, 20 participants from 12 social science disciplines at Sichuan University, Chengdu, China were observed using the proposed Discovery Service system. The user IS process characteristics and taxonomy were analysed, and the stages matrix of IS under new system was built.

Findings

Users’ IS processes under the new system proved to be very complex. The features of three process stages, i.e. searching, scanning and verifying stages, and four different behaviour patterns were identified. Moreover, characteristics of IS behaviour under the new service system were described.

Originality/value

User IS behaviour was addressed in a new service system context in this study, as has seldom been done in previous IS research. A comprehensive and user-centred understanding of users’ exploratory practices in a new service system context was obtained, which will inform the development of information services for digital libraries. In addition, it indicated that the uncertainty of the IS process should be addressed by considering the relationships among IS, information retrieval and user-computer interaction.

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Article
Publication date: 30 August 2021

Lifeng Wang, Huijiang Qu, Longlong Sun, Ziwang Xiao, Long Liu and Sharf Shajib Ahmad

Due to the deformation between the pylon and the girder caused by single tension of cables, the previously tensioned steel strands have stress relaxation, resulting in the actual…

35

Abstract

Purpose

Due to the deformation between the pylon and the girder caused by single tension of cables, the previously tensioned steel strands have stress relaxation, resulting in the actual cable forces being less than the design cable forces. To compensate the stress loss caused by the single tension of cables, this paper aims to present a practical compensation algorithm of stress relaxation during the construction period.

Design/methodology/approach

From the perspective of the essential cause of the stress relaxation, finite element analysis is used to solve the tension control force of each steel strand after a rigorous theoretical formula derivation.

Findings

The deformation and tension control force of each steel strand decrease with the advance of the tension sequence, and the decline rate drops gradually. However, the calculated force values of the steel strand are in good agreement with the measured value as the cable length decreases.

Originality/value

The previous rough calculation methods for the tension force of steel strands cannot meet the accuracy, and the accurate calculation methods often include the solution of nonlinear equations, which complicate the calculating process. Otherwise, there are few studies on the compensation of stress loss by calculating the deformation of the steel strand during the tension process. So, it developed an accurate and efficient algorithm to determine the tension control forces.

Details

Multidiscipline Modeling in Materials and Structures, vol. 17 no. 6
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 29 January 2021

Honggui Di, Shihao Huang, Longlong Fu and Binglong Wang

The paper aims to predict longitudinal deformation of a tunnel caused by grouting under the tunnel bottom in advance according to the grouting parameters, which can ensure the…

359

Abstract

Purpose

The paper aims to predict longitudinal deformation of a tunnel caused by grouting under the tunnel bottom in advance according to the grouting parameters, which can ensure the safety of the tunnel structure during the grouting process and also help to design the grouting parameters.

Design/methodology/approach

The paper adopted the analytical approach for calculating the longitudinal deformation of a shield tunnel caused by grouting under a tunnel, including usage of the Mindlin’s solution, the minimum potential energy principle and case validation.

Findings

The paper provides a variational method for calculating the longitudinal deformation of a shield tunnel in soft soil caused by grouting under the tunnel, which has high computational efficiency and accuracy.

Originality/value

This paper fulfils an identified need to study how the longitudinal deformation of a shield tunnel in soft soil caused by grouting under the tunnel can be calculated.

Details

Engineering Computations, vol. 38 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 16 January 2025

Long Wang, Fengtao Wang, Linkai Niu, Xin Li, Zihao Wang and Shuping Yan

The purpose of this paper is to combine triboelectric nanogeneration technology with ball bearing structure to achieve energy collection and fault monitoring.

11

Abstract

Purpose

The purpose of this paper is to combine triboelectric nanogeneration technology with ball bearing structure to achieve energy collection and fault monitoring.

Design/methodology/approach

In this paper, according to the rotation mode of ball bearings, the freestanding mode of triboelectric nanogeneration is selected to design and manufacture a novel triboelectric nanogeneration device Rolling Ball Triboelectric Nanogenerator (RB-TENG) which combines rotary energy collection with ball bearing fault self-sensing.

Findings

The 10,000s continuous operation experiment of the RB-TENG is carried out to verify its robustness. The accurate feedback relationship between the RB-TENG and rotation velocity can be demonstrated by the fitting comparison between the theoretical and experimental electrical signal periods at a certain time. By comparing the output electrical signals of the normal RB-TENG and the rotor spalling RB-TENG and polytetrafluoroethylene (PTFE) balls with different degrees of wear at 500 r/min, it can be concluded that the RB-TENG has an ideal monitoring effect on the radial clearance distance of bearings. The spalling fault test of the RB-TENG stator inner ring and rotor outer ring is carried out.

Originality/value

Through coupling experiments of rotor spalling fault of the RB-TENG and PTFE balls fault with different degrees of wear, it can be seen that when rotor spalling fault occurs, balls wear has a greater impact on the normal operation of the RB-TENG, and it is easier to identify. The fault self-sensing ability of the RB-TENG can be obtained, which is expected to provide an effective scheme for monitoring the radial wear clearance distance of ball bearings.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0295/

Details

Industrial Lubrication and Tribology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0036-8792

Keywords

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