Xiaokai Mu, Qingchao Sun, Wei Sun, Yunlong Wang, Chuanhua Wang and Xiaobang Wang
The traditional precision design only takes the influence of geometric tolerance of the parts and does not involve the load deformation in the assembly process. This paper aims to…
Abstract
Purpose
The traditional precision design only takes the influence of geometric tolerance of the parts and does not involve the load deformation in the assembly process. This paper aims to analyze the influence mechanism of flexible parts deformation on the geometric precision, and then to ensure the reliability and stability of the mechanical system.
Design/methodology/approach
Firstly, this paper adopts the N-GPS to analyze the influence mechanism of flexible parts deformation on the geometric precision and constructs a coupling 3D tolerance mathematical model of the geometric tolerance and the load deformation deviation based on the SDT theory, homogeneous coordinate transformation theory and surface authentication idea. Secondly, the least square method is used to fit the deformation surface of the mating surface under load so as to complete the conversion from the non-ideal element to the ideal element.
Findings
This paper takes the horizontal machining center as a case to obtain the deformation information of the mating surface under the self-weight load. The results show that the deformation deviation of the parts has the trend of transmission and accumulation under the load. The terminal deformation cumulative amount of the system is up to –0.0249 mm, which indicated that the influence of parts deformation on the mechanical system precision cannot be ignored.
Originality/value
This paper establishes a comprehensive 3D tolerance mathematical model, which comprehensively considers the effect of the dimensional tolerance, geometric tolerance and load deformation deviation. By this way, the assembly precision of mechanical system can be accurately predicted.
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Binbin Zhao, Yunlong Wang, Qingchao Sun, Yuanliang Zhang, Xiao Liang and Xuewei Liu
Assembly accuracy is the guarantee of mechanical product performance, and the characterization of the part with geometrical deviations is the basis of assembly accuracy analysis.
Abstract
Purpose
Assembly accuracy is the guarantee of mechanical product performance, and the characterization of the part with geometrical deviations is the basis of assembly accuracy analysis.
Design/methodology/approach
The existed small displacement torsors (SDT) model cannot fully describe the part with multiple mating surfaces, which increases the difficulty of accuracy analysis. This paper proposed an integrated characterization method for accuracy analysis. By analyzing the internal coupling relationship of the different geometrical deviations in a single part, the Monomer Model was established.
Findings
The effectiveness of the Monomer Model is verified through an analysis of a simulated rotor assembly analysis, and the corresponding accuracy analysis method based on the model reasonably predicts the assembly deviation of the rotor.
Originality/value
The Monomer Model realizes the reverse calculation of assembly deformation for the first time, which can be used to identify the weak links that affect the assembly accuracy, thus support the accuracy improvement in the re-assembly stage.
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Ziyang Jiang, Chang Zhang, Wenjun Ni and ShuangTian Li
This paper aims to study the problem of starvation lubrication of high-speed ball bearings due to temperature rise during operation and to avoid thermal failure of bearing…
Abstract
Purpose
This paper aims to study the problem of starvation lubrication of high-speed ball bearings due to temperature rise during operation and to avoid thermal failure of bearing lubrication.
Design/methodology/approach
Under the quasi-statics model of grease lubrication, both the oil film dragging force and the rolling friction between the balls and raceways collectively counteract the gyroscopic torque. Initially, the static model for grease lubrication is solved, followed by calculating the generated heat using the local heat generation method and ultimately the multinodal thermal network model is solved, and the solved results of the quasi-statics are updated by the temperatures of the grease nodes based on the relationship of the grease temperature and viscosity, as well as the relationship of the viscosity and the film thickness.
Findings
By comparing the numerical calculation results of bearings under different working conditions, the influence of starvation lubrication on the oil film thickness, oil film drag force and rolling friction of bearings is discussed, and it is found that the numerical calculation results of the outer ring temperature of bearings under the starvation lubrication due to the consideration of temperature rise are closer to the experimental values.
Originality/value
This study reveals the dynamic characteristics of bearings under starvation lubrication, which is more practical and engineering guiding significance for the design of bearings, and introduces a new method and basis for the calculation of temperature rise of rolling bearings.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0208/
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Gang Liu, Wannan Wang, Yunlong Duan, Tachia Chin and Francesco Mirone
Digital technologies have transformed business management practices and adapted them to shorter product lifecycles. As a result, firms are shifting their approach to building new…
Abstract
Purpose
Digital technologies have transformed business management practices and adapted them to shorter product lifecycles. As a result, firms are shifting their approach to building new competitive advantage from cost-oriented to entrepreneurial orientation (EO). This study aims to analyze the innovation performance (IP) in the context of EO from a knowledge management perspective. It constructs the functional path of the relationships among EO, knowledge coupling (KC) and IP of Chinese manufacturing firms to achieve business success.
Design/methodology/approach
Using data from 157 listed Chinese manufacturing firms from 2012 to 2021, the authors construct a panel data model to test the effect of EO on IP. This study classifies KC into existing knowledge coupling (EKC) and new and existing knowledge coupling (NKC) and analyzes their mediating effects in the above relationships.
Findings
This study finds that EO has an insignificant, inverted U-shaped relationship with IP. Both EKC and NKC have a significant, inverted U-shaped relationship with IP; in other words, if EKC and NKC increase, the IP of Chinese manufacturing firms first increases and then decreases, and EKC and NKC have a complete mediating effect on the relationship between EO and IP.
Originality/value
This study provides an in-depth analysis of IP from an EO perspective. The study’s findings enrich and extend the theoretical relationship between EO and IP. The authors also propose a knowledge management perspective for entrepreneurship research. These findings improve the current understanding of the role and function of KC in EO.
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Yunlong Li, Zhinong Li, Dong Wang and Zhike Peng
The purpose of this paper is to discuss the asymptotic models of different parts with a pitting fault in rolling bearings.
Abstract
Purpose
The purpose of this paper is to discuss the asymptotic models of different parts with a pitting fault in rolling bearings.
Design/methodology/approach
For rolling bearings with a pitting fault, the displacement deviation between raceways and rolling elements is usually considered to vary instantaneously. However, the deviation should change gradually. Based on this shortcoming, the variation rule and calculation method of the displacement deviation are explored. Asymptotic models of different parts with a pitting fault are discussed, respectively. Besides, rolling bearing systems have prominent fractional characteristics unconsidered in the traditional models. Therefore, fractional calculus is introduced into the modeling of rolling bearings. New dynamic asymptotic models of different parts with a pitting fault are proposed based on fractional damping. The numerical simulation is performed based on the proposed model, and the dynamic characteristics are analyzed through the bifurcation diagrams, trajectory diagrams and frequency spectrograms.
Findings
Compared with the model based on integral calculus, the proposed model can better reflect the periodic characteristics and fault characteristics of rolling bearings. Finally, the proposed model is verified by the experiment. The dynamic characteristics of rolling bearings at different rotating speeds are analyzed. The experimental results are consistent with the simulation results. Therefore, the proposed model is effective.
Originality/value
(1) The above models are idealized, i.e. the local pitting fault is treated as a rectangle. When a component comes into contact with the fault, the displacement deviation between the component and the fault component immediately releases if the component enters the fault area and restores if the component leaves. However, the displacement deviation should change gradually. Only when the component touches the fault bottom, the displacement deviation reaches the maximum. (2) Due to the material's memory and fluid viscoelasticity, rolling bearing systems exhibit significant fractional characteristics. However, the above models are all proposed based on integral calculus. Integral calculus has some local characteristics and is not suitable for describing historical dependent processes. Fractional calculus can better describe the essential characteristics of the system.
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Yunlong Duan, Kun Wang, Hong Chang, Wenjing Liu and Changwen Xie
This paper aims to investigate the following issues: the mechanisms through which different types of top management team’s social capital influence the innovation quality of…
Abstract
Purpose
This paper aims to investigate the following issues: the mechanisms through which different types of top management team’s social capital influence the innovation quality of high-tech firms, and the moderating effect of organizational knowledge utilization on the relationship between top management team’s social capital and innovation quality in high-tech firms.
Design/methodology/approach
This study categorizes top management team’s social capital into political, business and academic dimensions, investigating their impact on innovation quality in high-tech firms. Furthermore, a research model is developed with organizational knowledge utilization as the moderating variable. Data from Chinese high-tech firms between 2010 and 2019 are collected as samples for analysis.
Findings
The innovation quality of high-tech firms shows an inverted U-shaped trend as the top management team’s political capital and business capital increase. The top management team’s academic capital has a significantly positive correlation with the innovation quality of high-tech firms. Moreover, organizational knowledge utilization plays a significant moderating role in the relationship between the top management team’s social capital and innovation quality in high-tech firms.
Originality/value
This study explores the relationship among different dimensions of top management team’s social capital, innovation quality and organizational knowledge utilization. It holds significant theoretical value in enriching and refining the interactions between top management team’s social capital, knowledge management theory and innovation management theory. In addition, it offers important practical implications for firms to rationally approach top management team’s social capital, emphasize top management team configuration management and establish a comprehensive and efficient organizational knowledge utilization mechanism.
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Yunlong Shi, Liang Wang and Xiaoming Qian
The purpose of this paper is to compare the evaporative resistance and thermal insulation of clothing measured by thermal manikin “Walter” using uniform and non-uniform skin.
Abstract
Purpose
The purpose of this paper is to compare the evaporative resistance and thermal insulation of clothing measured by thermal manikin “Walter” using uniform and non-uniform skin.
Design/methodology/approach
The non-uniform skin with different perspiration rates was made by laminating a silicone layer on the inner side of a uniform skin. The thermal manikin was then covered with prepared non-uniform skin as well as uniform one. Four types of clothing ensembles were tested.
Findings
The relative intensity of perspiration rate was realized in different part of “Walter” skin, which was close to the perspiration rate of human being. There was a strong correlation between uniform skin and non-uniform skin. The thermal insulation and evaporative resistance of clothing measured on the non-uniform skin were higher than the ones determined on the uniform skin. However, their moisture permeability index showed the reversed tendency.
Research limitations/implications
The implication of the research is to investigate the differences between uniform skin and non-uniform skin for manikin “Walter.” This is possibly useful in correcting and predicting more accurate thermal insulation and evaporative resistance of clothing measured by “Walter” with a uniform skin in future.
Originality/value
It was more accurate using non-uniform skin in evaluating thermal and wet comfort comparing to uniform skin.
Details
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Lingzhi Li, Shilong Jiang, Jingfeng Yuan, Lei Zhang, Xiaoxiao Xu, Jing Wang, Yilun Zhou, Yunlong Li and Jin Xu
Existing hospital building operations involve numerous information technology applications and complex building systems; therefore, an intelligent facility management (FM…
Abstract
Purpose
Existing hospital building operations involve numerous information technology applications and complex building systems; therefore, an intelligent facility management (FM) platform is required to ensure their continuous operation. To address the persistent issues of data silos, inefficient data interoperability, and workflow incoordination that have been identified in the current body of FM practice and literature, the present study develops a data-asset (DA) centric FM platform specifically designed for hospital buildings.
Design/methodology/approach
This study proposes a semi-customized approach to develop the DA-centric FM platform for hospital buildings. To elucidate the precise function requirements of the hospital FM platform, focus group interviews are employed. By seamlessly integrating the as-built BIM model, IoT sensor data and FM workflow data, the BIM-based DA model with a data transfer mechanism is developed. The development of the FM platform with function modules in a case study is guided by a five-tier architecture and the coordination theory (CT). The case study provides an in-depth introduction to the applications of DA management, space management and maintenance management modules.
Findings
The capabilities of the developed DA-centric hospital FM platform are validated through the case application and user satisfaction survey, which assess data quality, automation level, operation efficiency, flexibility and functionality. For hospital FM activities, this DA-centric FM platform realizes data integration and seamless transformation, optimizes workflow coordination and enhances operation performance.
Originality/value
The initial scholarly contribution is the establishment of the BIM-based DA model, which serves as the data middle platform for continuous data integration, transmission and sharing within the FM platform. Subsequently, under the guidance of the CT, the business process of function modules is designed, improving the intra-module and inter-module workflow coordination. The developed DA-centric FM system along with its performance benchmarking application, assists facility managers and decision-makers in implementing smart operations for hospital buildings and achieving the management goals of safety, efficiency, energy savings and convenience.
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Lili Wang, Ying’ao Liu, Jingdong Duan and Yunlong Bao
This study aims to enhance the lubrication performance of thrust bearings. The influence of columnar convex–concave compound microtexture on bearing performance is investigated
Abstract
Purpose
This study aims to enhance the lubrication performance of thrust bearings. The influence of columnar convex–concave compound microtexture on bearing performance is investigated
Design/methodology/approach
Based on the compound microtexture model of thrust bearings, considering surface roughness and turbulent effect, the variation of lubrication characteristics with the change in the compound microtexture parameters is studied.
Findings
The results indicate that, compared with circular microtexture, the maximum pressure of compound microtexture of thrust bearings increases by 7.42%. Optimal bearing performance is achieved when the internal microtexture depth is 0.02 mm. Turbulent flow states and surface roughness lead to a reduction in the optimal depth. The maximum pressure and load-carrying capacity of the bearing decrease as the initial angle increases, whereas the friction coefficient increases with the increase in the initial angle. The lubrication performance is best for bearings with a circumferential parallel arrangement of microtexture.
Originality/value
The novel composite microtexture with columnar convex-concave is proposed, and the computational model of thrust bearings is set. The influence of surface roughness and turbulent flow on the bearing performance should be considered for better conforming with engineering practice. The effect of microtexture depth, arrangement method and distribution position on the lubrication performance of the compound microtexture thrust bearing is investigated, which is of great significance for improving tribology, thrust bearings and surface microtexture theory.
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Yunlong Tang and Yaoyao Fiona Zhao
This paper aims to provide a comprehensive review of the state-of–the-art design methods for additive manufacturing (AM) technologies to improve functional performance.
Abstract
Purpose
This paper aims to provide a comprehensive review of the state-of–the-art design methods for additive manufacturing (AM) technologies to improve functional performance.
Design/methodology/approach
In this survey, design methods for AM to improve functional performance are divided into two main groups. They are design methods for a specific objective and general design methods. Design methods in the first group primarily focus on the improvement of functional performance, while the second group also takes other important factors such as manufacturability and cost into consideration with a more general framework. Design methods in each groups are carefully reviewed with discussion and comparison.
Findings
The advantages and disadvantages of different design methods for AM are discussed in this paper. Some general issues of existing methods are summarized below: most existing design methods only focus on a single design scale with a single function; few product-level design methods are available for both products’ functionality and assembly; and some existing design methods are hard to implement for the lack of suitable computer-aided design software.
Practical implications
This study is a useful source for designers to select an appropriate design method to take full advantage of AM.
Originality/value
In this survey, a novel classification method is used to categorize existing design methods for AM. Based on this classification method, a comprehensive review is provided in this paper as an informative source for designers and researchers working in this field.