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…
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
Keywords
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…
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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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…
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.
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Keywords
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…
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.
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Keywords
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.
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/