Ruidong Xie, Dichen Li, Bin Cui, Lianzhong Zhang and Feng Gao
Laser metal deposition (LMD) is an important additive manufacturing (AM) technology, but the metallurgical defects, such as cracks and porosities, produced in LMD process will…
Abstract
Purpose
Laser metal deposition (LMD) is an important additive manufacturing (AM) technology, but the metallurgical defects, such as cracks and porosities, produced in LMD process will seriously affect the mechanical properties of the parts. The purpose of this paper is to propose a novel in-process defects detection method based on infrared scanning for LMD.
Design/methodology/approach
The defects detection principle is that, after every three to five layers have been deposited, the optical head of a high-precision infrared two-color pyrometer is driven to scan the defects by measuring the abnormal temperature peaks on the deposited surface. The experiments for verifying the defects detection principle were carried out.
Findings
The relationship between the temperature peak value and the dimensions of the defect was analyzed based on the heat conduction theory and curves of temperature peak value versus crack width or diameter of porosity.
Originality/value
This method can effectively improve the detection accuracy and the defects can be precisely located, which can meet the requirement of laser targeting re-melting and elimination of the defects.
Details
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Xiaojing Feng, Bin Cui, Yaxiong Liu, Lianggang Li, Xiaojun Shi and Xiaodong Zhang
The purpose of this paper is to solve the problems of poor mechanical properties, high surface roughness and waste support materials of thin-walled parts fabricated by…
Abstract
Purpose
The purpose of this paper is to solve the problems of poor mechanical properties, high surface roughness and waste support materials of thin-walled parts fabricated by flat-layered additive manufacturing process.
Design/methodology/approach
This paper proposes a curved-layered material extrusion modeling process with a five-axis motion mechanism. This process has advantages of the platform rotating, non-support printing and three-dimensional printing path. First, the authors present a curved-layered algorithm by offsetting the bottom surface into a series of conformal surfaces and a toolpath generation algorithm based on the geodesic distance field in each conformal surface. Second, they introduce a parallel five-axis printing machine consisting of a printing head fixed on a delta-type manipulator and a rotary platform on a spherical parallel machine.
Findings
Mechanical experiments show the failure force of the five-axis printed samples is 153% higher than that of the three-axis printed samples. Forming experiments show that the surface roughness significantly decreases from 42.09 to 18.31 µm, and in addition, the material consumption reduces by 42.90%. These data indicate the curved-layered algorithm and five-axis motion mechanism in this paper could effectively improve mechanical properties and the surface roughness of thin-walled parts, and realize non-support printing. These methods also have reference value for other additive manufacturing processes.
Originality/value
Previous researchers mostly focus on printing simple shapes such as arch or “T”-like shape. In contrast, this study sets out to explore the algorithm and benefits of modeling thin-walled parts by a five-axis machine. Several validated models would allow comparability in five-axis printing.
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Shuang Han, Jing Zhang, Quanyue Yang, Zijian Yuan, Shubin Li, Fengying Cui, Chuntang Zhang and Tao Wang
The performance of the classical car-following system is easily affected by external disturbances. To enhance the performance of the classical car-following model under sudden…
Abstract
Purpose
The performance of the classical car-following system is easily affected by external disturbances. To enhance the performance of the classical car-following model under sudden external disturbances, a novel car-following model is established to smooth traffic flow.
Design/methodology/approach
This paper proposed a Proportion Integration Differentiation (PID) control strategy based on classical control theory and developed a novel car-following model. The linear system theory and Laplace transform are used to derive a closed-loop transfer function. Then, the stability condition is obtained by using the Routh stability criterion and the small gain theorem. Finally, the validity and feasibility of the PID control strategy is proved by numerical simulations.
Findings
The analytic results and the numerical simulation results show that both the integration part and the differential part have the positive effect to suppress traffic oscillation efficiently; the collaboration of these two parts has more power to improve the stability of traffic flow. It means that the proposed model integrated with the PID control strategy has the ability of anti-interference and smooth traffic compared with the classical car-following model.
Originality/value
This paper introduces the PID control strategy into the classical car-following system, which enhances the stability of the system and also provides an efficient method for optimizing the traffic flow system.
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Jianwei Cui, Linwei Cui and Huice Jiang
Managing archives using robots rather than people can considerably enhance efficiency, while need to modify the structure of archive shelves or installation tracks. This paper…
Abstract
Purpose
Managing archives using robots rather than people can considerably enhance efficiency, while need to modify the structure of archive shelves or installation tracks. This paper aims to develop a fully automated archive access robot without modification.
Design/methodology/approach
First, a mobile navigation chassis and a motion algorithm based on laser ranging and map matching are created for autonomous movement to any of the archives’ locations. Second, because the existing archives are stacked vertically, the bionic manipulator is made to mimic the movement of manual access to the archives, and it is attached to the robot arm’s end to access different layers of archives. In addition, an industrial camera is used to complete barcode identification of the archives and acquire data on their location and thickness. Finally, the archive bin is created to store archives.
Findings
The robot can move, identify and access multiple archival copies placed on floors 1–6 and 2–5 cm thick autonomously without modifying the archival repository or using auxiliary devices.
Research limitations/implications
The robot is currently able to navigate, identify and access files placed on different levels. In the future, the speed of the robot’s navigation and the movement of the robot arm could be even faster, while the level of visualization of the robot could be further improved and made more intelligent.
Practical implications
The archive access robot developed by the authors makes it possible for robots to manage archives instead of human, while being cheaper and easier to deploy than existing robots, and has already been tested in the archive storage room of the State Grid maintenance branch in Jiangsu, China, with better results.
Social implications
The all-in-one archive access robot can replace existing robotic access solutions, promote intelligent management of the archive industry and the construction of unmanned archive repositories and provide ideas for the development of robots for accessing book-like materials.
Originality/value
This study explores the use of robots to identify and access archives without changing archive shelves or installing auxiliary devices. In this way, the robot can be quickly applied to the storage room to improve the efficiency of archive management.
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Sushant Kumar and Jung-Kuei Hsieh
Increasingly brands are performing several activities on social media in order to alter consumer consumption towards their offering. However, limited studies have attempted to…
Abstract
Purpose
Increasingly brands are performing several activities on social media in order to alter consumer consumption towards their offering. However, limited studies have attempted to understand as how activities on social media influence usage intentions and brand loyalty. Thus, this study aims to examine the influence of social media marketing activities (SMMA) on brand experience and its association with continued usage intentions (CUI) and brand loyalty.
Design/methodology/approach
The study conceptualized a research model by using the theoretical premise of stimulus-organism-response theory. SMMA acts as stimulus, four (sensory, affective, behavioral and intellectual) elements of brand experience act as organism, and CUI and brand loyalty act as response. A survey-based questionnaire is used to collect data from 309 respondents. The hypothesized associations of research model were examined using the structural equation modeling approach.
Findings
Results of the study are in line with hypothesized associations among constructs. Results suggest that SMMA is associated with all four elements of brand experience. Also, affective, behavioral and intellectual aspects of brand experience are associated with CUI which influence brand loyalty. The moderating role of education on hypothesized association and the mediating role of organism are also confirmed.
Originality/value
Using stimulus-organism-response theory, this study confirms that SMMA are associated with sensory, affective, behavioral and intellectual aspect of brand experience which has not been examined so far. Also, the novel findings of study add to existing literature of SMMA, brand experience and brand loyalty. The study further contributes to literature by showing the moderation effect of education.
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Yunyun Yuan, Pingqing Liu, Bin Liu and Zunkang Cui
This study aims to investigate how small talk interaction affects knowledge sharing, examining the mediating role of interpersonal trust (affect- and cognition-based trust) and…
Abstract
Purpose
This study aims to investigate how small talk interaction affects knowledge sharing, examining the mediating role of interpersonal trust (affect- and cognition-based trust) and the moderating role of perceived similarity among the mechanisms of small talk and knowledge sharing.
Design/methodology/approach
This research conducts complementary studies and collects multi-culture and multi-wave data to test research hypotheses and adopts structural equation modeling to validate the whole conceptual model.
Findings
The research findings first reveal two trust mechanisms linking small talk and knowledge sharing. Meanwhile, the perceived similarity between employees, specifically, strengthens the affective pathway of trust rather than the cognitive pathway of trust.
Originality/value
This study combines Interaction Ritual Theory and constructs a dual-facilitating pathway approach that aims to reveal the impact of small talk on knowledge sharing, describing how and when small talk could generate a positive effect on knowledge sharing. This research provides intriguing and dynamic insights into understanding knowledge sharing processes.
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Bin Chen, Yuan Wang, Shaoqing Cui, Jiansheng Xiang, John-Paul Latham and Jinlong Fu
Accurate presentation of the rock microstructure is critical to the grain-scale analysis of rock deformation and failure in numerical modelling. 3D granite microstructure…
Abstract
Purpose
Accurate presentation of the rock microstructure is critical to the grain-scale analysis of rock deformation and failure in numerical modelling. 3D granite microstructure modelling has only been used in limited studies with the mineral pattern often remaining poorly constructed. In this study, the authors developed a new approach for generating 2D and 3D granite microstructure models from a 2D image by combining a heterogeneous material reconstruction method (simulated annealing method) with Voronoi tessellation.
Design/methodology/approach
More specifically, the stochastic information in the 2D image is first extracted using the two-point correlation function (TPCF). Then an initial 2D or 3D Voronoi diagram with a random distribution of the minerals is generated and optimised using a simulated annealing method until the corresponding TPCF is consistent with that in the 2D image. The generated microstructure model accurately inherits the stochastic information (e.g. volume fraction and mineral pattern) from the 2D image. Lastly, the authors compared the topological characteristics and mechanical properties of the 2D and 3D reconstructed microstructure models with the model obtained by direct mapping from the 2D image of a real rock sample.
Findings
The good agreements between the mapped and reconstructed models indicate the accuracy of the reconstructed microstructure models on topological characteristics and mechanical properties.
Originality/value
The newly developed reconstruction method successfully transfers the mineral pattern from a granite sample into the 2D and 3D Voronoi-based microstructure models ready for use in grain-scale modelling.
Details
Keywords
Bin Xie, Zhenyu Wang, Yiling Xu and Libing Cui
Emergencies have become a growing concern for organizations, which require flexibility to respond to changes in emergencies based on their contingency, dynamic evolution rapidly…
Abstract
Purpose
Emergencies have become a growing concern for organizations, which require flexibility to respond to changes in emergencies based on their contingency, dynamic evolution rapidly and other characteristics. In order to enhance the ability of engineering project organizations to cope with emergencies, this study explores the mechanism of its influence on knowledge innovation under emergencies from the perspective of bricolage theory, and provides a new perspective for the traditional preplanning-based handling of emergencies by improvising to enhance the ability and results of improvisation.
Design/methodology/approach
Firstly, a structural equation model of the relationship between bricolage and knowledge innovation was constructed by introducing improvisational behavior and serendipity as mediating and moderating variables of the relationship between bricolage and knowledge innovation based on bricolage theory; secondly, drawing on previous well-established measurement scales about bricolage, improvisational behavior, knowledge innovation and serendipity, a questionnaire survey was conducted with different types of engineering project managers and technicians in Gansu Province as the research subjects, and 238 valid questionnaires were returned; finally, validation factor analysis and correlation analysis were performed, and the hypothesized relationships were verified using AMOS 24.0 software.
Findings
The results show that bricolage positively influences improvisational behavior; improvisational behavior positively influences knowledge innovation; bricolage positively influences knowledge innovation; bricolage influences knowledge innovation through the mediating role of improvisational behavior and serendipity positively moderates the impact of resource bricolage on knowledge innovation.
Originality/value
It reveals the mechanism of knowledge innovation of engineering project organizations in response to emergencies and the innovation mechanism of the episodic nature of emergency decision-making, extends the applicable context of bricolage theory and provides a new perspective for engineering project organizations in response to emergencies.
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Moral hazard and adverse selection often exist in asymmetric information environment. In this paper, quality investment decision problem is studied under moral hazard. A basic…
Abstract
Moral hazard and adverse selection often exist in asymmetric information environment. In this paper, quality investment decision problem is studied under moral hazard. A basic model for quality investment level decision is developed with the supplier as a principal and the buyer as an agent. And then we regard the supplier and the buyer’s rational limitations to set up a model when the buyer’s quality evaluation and processing activities are hidden. The model is optimized and the results under different backgrounds are discussed and compared. Results show that the buyer’s quality evaluation level and processing level are mostly influenced by the supplier’s quality assurance payment. Both the supplier and the buyer choose different quality investment levels under moral hazard because of the supplier’s payment to the buyer in case of internal failure and external failure.
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Gangxiang Xu, Bin Guo, Wen Li and Xiaoting Wang
The purpose of this paper is to use the theoretical perspective of structural inertia as a unique lens to study foreign sequential entry mode choices of multinational firms.
Abstract
Purpose
The purpose of this paper is to use the theoretical perspective of structural inertia as a unique lens to study foreign sequential entry mode choices of multinational firms.
Design/methodology/approach
It adopts quantitative analysis of a sample of 121 Chinese publicly listed firms with 564 foreign entry incidents in the 2001-2012 period to test the hypotheses.
Findings
The empirical results show that multinational firms have a tendency to adopt the same mode in the subsequent entry as the number of prior entry mode choice of a given type (joint venture (JV) in this study) increases. The results support the theoretical prediction that organizations repeat their past activities due to structural inertia. Moreover, such an inertia effect in foreign sequential entry mode choices becomes stronger for older multinational firms, larger multinational firms and state-owned multinational firms.
Research limitations/implications
Consistent with existing research, this study focuses on the entry mode choice between JV and wholly owned subsidiaries. However, it is better to examine the relationship identified in the study for different types of entry mode choices to assess result generalizability.
Practical implications
It reminds managers of multinational firms that they should be cautious to the influence of structural inertia that can be a barrier to strategic flexibility when they make entry mode choices.
Originality/value
The main contribution of this study resides in introducing structural inertia perspective to help understand the determinants of foreign sequential entry mode choices of multinational firms.