Shijie Jiang, Mingyu Sun, Yang Zhan, Hui Li and Wei Sun
The purpose of this study is to set up a dynamic model of material extrusion (ME) additive manufacturing plates for the prediction of their dynamic behavior (i.e. dynamic inherent…
Abstract
Purpose
The purpose of this study is to set up a dynamic model of material extrusion (ME) additive manufacturing plates for the prediction of their dynamic behavior (i.e. dynamic inherent characteristic, resonant response and damping) and also carry out its experimental validation and sensitivity analysis.
Design/methodology/approach
Based on the classical laminated plate theory, a dynamic model is established using the orthogonal polynomials method, taking into account the effect of lamination and orthogonal anisotropy. The dynamic inherent characteristics of the ME plate are worked out by Ritz method. The frequency-domain dynamic equations are then derived to solve the plates’ resonant responses, with which the damping ratio is figured out according to the half-power bandwidth method. Subsequently, a series of experimental tests are performed on the ME samples to obtain the measured data.
Findings
It is shown that the predictions and measurements in terms of dynamic behavior are in good agreement, validating the accuracy of the developed model. In addition, sensitivity analysis shows that increasing the elastic modulus or Poisson’s ratio will increase the corresponding natural frequency of the ME plate but decrease the resonant response. When the density is increased, both the natural frequency and resonant response will be decreased.
Research limitations/implications
Future research can be focused on using the proposed model to investigate the effect of processing parameters on the ME parts’ dynamic behavior.
Practical implications
This study shows theoretical basis and technical insight into improving the forming quality and reliability of the ME parts.
Originality/value
A novel reliable dynamic model is set up to provide theoretical basis and principle to reveal the physical phenomena and mechanism of ME parts.
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Shijie Jiang, Yannick Siyajeu, Yinfang Shi, Shengbo Zhu and He Li
The purpose of this study is to investigate the efficiency of applied vibration in improving the forming quality (mechanical property and dynamics characteristics) of fused…
Abstract
Purpose
The purpose of this study is to investigate the efficiency of applied vibration in improving the forming quality (mechanical property and dynamics characteristics) of fused filament fabrication (FFF) parts.
Design/methodology/approach
A vibrating FFF three-dimensional printer was set up, with which the samples fabricated in different directions were manufactured separately without and with vibration applied. A series of experimental tests, including tensile tests, dynamics tests and scanning electron microscopy (SEM) tests, were performed on these samples to experimentally quantify the effect of applied vibration on their forming quality.
Findings
It has been found that the applied vibration can significantly increase the tensile strength and plasticity of the samples built in Z-direction, and obviously decrease the orthogonal anisotropy. It can also significantly change the sample’s natural frequency, decrease the resonant response and increase the modal damping ratio, thus improve the anti-vibration capability of FFF samples. In addition, the SEM analysis confirmed that applying vibration into FFF process could improve the forming quality of the fabricated part.
Research limitations/implications
Future research may be focused on investigating the efficiency of applied vibration in improving the forming quality of parts fabricated by the other additive manufacturing techniques.
Practical implications
This study helps to improve the reliability of FFF parts and extend the application range of FFF technology.
Originality/value
A novel method to improve the forming quality of FFF parts is provided and the available information about the performance of dynamics characteristics.
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Rabia Shahid, Humera Shahid, Li Shijie, Faiq Mahmood and Ning Yifan
Using the Shanghai pilot free trade zone (SPFTZ) as the testing ground for further reform and opening up,the links between global value chain (GVC) and pilot free trade zone…
Abstract
Purpose
Using the Shanghai pilot free trade zone (SPFTZ) as the testing ground for further reform and opening up,the links between global value chain (GVC) and pilot free trade zone (PFTZ) programs are mutually reinforcing. GVC creates opportunities for companies to use PFTZ to reduce their costs and increase their competitiveness, while PFTZ can facilitate the movement of goods within GVC and promote the development of GVC by attracting foreign investment. Overall, in SPFTZ, the industrial structure is promoted due to trade and investment facilitation, innovation promotion, and comprehensive service platform inside SPFTZ.
Design/methodology/approach
This study examined industrial upgrading in GVC (IUGVC) using five indicators under three quantitative dimensions: product, process, and skill upgrading. Difference-in-Differences (DID) model is employed for the impact assessment of SPFTZ. Parallel trend analysis and Granger causality analysis are performed to check the reliability of DID outcome. Finally, robustness test using exogenous control variables are carried out.
Findings
A positive impact of SPFTZ is found on IUGVC, which is due to promoting effect of SPFTZ on foreign direct investment and technological innovation. Based on the study's findings, policy recommendations are given, such as providing business support to enterprises operating inside a PFTZ.
Originality/value
From a GVC perspective, the impact of theSPFTZ establishment on IUGVC cannot be ignored, and is so far missing in the literature.
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Shijie Song, Yuxiang Chris Zhao, Xinlin Yao, Zhichao Ba and Qinghua Zhu
Hedonic social applications have been increasingly popular among health information consumers. However, it remains unclear what motivates consumers to adopt health information in…
Abstract
Purpose
Hedonic social applications have been increasingly popular among health information consumers. However, it remains unclear what motivates consumers to adopt health information in hedonic applications when they have alternative choices of more formal health information sources. Building on the self-determination theory and the affordances lens, this study aims to investigate how different affordances on hedonic social applications affect consumers' basic psychological needs and further influence their intention to adopt health information on such applications.
Design/methodology/approach
As TikTok demonstrated great potential in disseminating health information, we developed a model that we analyze using the PLS-SEM technique with data collected from a valid research sample of 384 respondents with health information seeking or encountering experience in TikTok.
Findings
The results suggested that health information adoption in hedonic social applications is significantly predicted by the satisfaction of consumers' basic psychological needs, namely autonomy, relatedness and competence. Moreover, the satisfaction of basic psychological needs is positively affected by affordances provided by the hedonic social applications. The hedonic affordances positively influence autonomy satisfaction, while the connective affordances positively affect relatedness satisfaction, and the utilitarian affordances positively support competence satisfaction.
Originality/value
The study indicates that hedonic social applications such as TikTok could be an important channel for consumers to access and adopt health information. The study contributes to the literature by proposing a theoretical model that explains consumers' health information adoption and yields practical implications for designers and service providers of hedonic social applications.
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Shijie Song, Yuxiang Chris Zhao, Xinlin Yao, Zhichao Ba and Qinghua Zhu
Although leveraging social media to access healthcare information is nothing new, a boom in short video apps offers new potential for disseminating health-related information…
Abstract
Purpose
Although leveraging social media to access healthcare information is nothing new, a boom in short video apps offers new potential for disseminating health-related information. However, it is still unclear how short video apps might facilitate and benefit users’ consumption of health information. Furthermore, the technology features of short video apps complicate attempts to conduct research about them; as a consequence, they have been understudied. For addressing these concerns, this study adopts an affordance perspective to investigate the relationship between affordances and user experience and to examine factors that contribute to users’ intention to continue using short video apps to obtain health information.
Design/methodology/approach
Drawing upon affordance theory, we constructed a research model that integrates four types of affordances (livestreaming, searching, meta-voicing and recommending), three types of user experience (immersion, social presence and credibility perception), and user’s intention to continue use. We employed an online survey and obtained a sample of 372 valid responses from TikTok (DouYin) users in China. The partial least squares (PLS) method was used to analyze the data.
Findings
The study found that the user experience, in terms of social presence, immersion and credibility perception, can significantly predict users’ intention to continue using short video apps to obtain health information. Furthermore, the user experience was positively associated with the different affordances provided by the short video apps.
Originality/value
The findings of this study have several implications. First, the study contributes to the health information behavior literature by incorporating the aspect of user experience. Moreover, the study extends the application of affordance theory to users’ health information acquisition, and it carries some practical implications on how to leverage the great potential of short video apps to serve public health communication better.
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Shufeng Tang, Ligen Qi, Guoqing Zhao, Hong Chang, Shijie Guo and Xuewei Zhang
The purpose of this paper is to design a new type of magnetic suction wall-climbing robot suitable for the wall inspection of wind turbine towers to solve the problems in manual…
Abstract
Purpose
The purpose of this paper is to design a new type of magnetic suction wall-climbing robot suitable for the wall inspection of wind turbine towers to solve the problems in manual maintenance tasks.
Design/methodology/approach
By analyzing the shortcomings of existing wall-climbing robots, a magnetic suction integrated wheel structure is designed to effectively combine the adsorption structure and transmission structure. To enable the robot to adapt to the curvature of the wall surface of a wind turbine tower, a passive adaptive curvature structure is designed. The effects of the air gap, the thickness of the wheel plates on both sides, the size of permanent magnets and the size of aluminum rings on the adsorption force are studied. Through mechanical model analysis under different instability conditions, the magnetic circuit of the magnetic wheel is optimized and designed.
Findings
Applying the wall-climbing robot to engineering practice, experiments have shown that the developed wall-climbing robot can move safely and stably on the wall of the wind turbine tower. The robot can also carry a load of 20 kg, and the designed adaptive structure can cause the magnetic wheel to deflect up to 20° relative to the vehicle body, fully meeting the curvature requirements of the minimum diameter end of the wind turbine tower.
Originality/value
This paper proposes a magnetic suction integrated wheel structure through analysis of the working environment. And the parameters affecting the magnetic wheel adsorption performance were optimized. Meanwhile, a passive adaptive wind turbine tower curvature structure was proposed.
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Shufeng Tang, Guoqing Zhao, Yun Zhi, Ligen Qi, Renjie Huang, Hong Chang, Shijie Guo and Xuewei Zhang
This paper aims to solve the problem of uncertain position and attitude between unstructured terrain robot and grasped target and insufficient control accuracy in extreme…
Abstract
Purpose
This paper aims to solve the problem of uncertain position and attitude between unstructured terrain robot and grasped target and insufficient control accuracy in extreme environment, a grasping mechanism based on attraction domain relationship is proposed, which can realize autonomous positioning, capturing and grasping of robot under low control accuracy.
Design/methodology/approach
The grasping mechanism was designed, taking inspiration from fishing behavior this mechanism introduces attraction domains and flexible-elastic structures through the active and passive ends to achieve automatic positioning and capture. After the capture is completed, the grasping mechanism connects the active end and the passive end, simultaneously relying on the gravity of the target object to achieve locking and release between the robot and the target object. This paper adopts theoretical, simulation and experimental verification methods to conduct theoretical and simulation analysis on the autonomous positioning and grasping process of the mechanism, and produces grasping experimental prototypes with different positions and postures.
Findings
The experiment shows that the gripping mechanism designed in this paper can achieve automatic positioning capture and gripping of large deviation situations under low control accuracy, with a displacement deviation of up to 10 mm (about 1/6 diameter of the end of the mechanism) and an angle deviation of up to 3°. The scientific research task in the extremely high altitude environment has finally been successfully accomplished.
Originality/value
Inspired by fishing behavior, this paper proposes a positioning, capturing and grasping mechanism. The attraction area built with permanent magnets, coupled with the flexible connection, enables precise capture under low control, while the grasping mechanism can also rely on gravity to self-lock and release.
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This paper seeks to discuss the genealogical sources for Chinese immigrants as well as the settlement of Chinese in the USA and the historical evolution of Chinese names, their…
Abstract
Purpose
This paper seeks to discuss the genealogical sources for Chinese immigrants as well as the settlement of Chinese in the USA and the historical evolution of Chinese names, their origins, arrangement and development. It aims to cover the origins of various classes of Chinese surnames, followed by the content description of a traditional genealogical book for jiapu.
Design/methodology/approach
The paper researches the various ways that a Chinese person can find out about their ancestry.
Findings
The paper reveals the roles of libraries, including serving the needs of patrons interested in genealogical research, preserving and interpreting information through oral and family history projects and collaborating with other libraries through interlibrary loan, document delivery, library consortia, collection management and international resource‐sharing.
Research limitations/implications
The study provides information on where and how to locate the genealogical resources for researching the genealogy of a Chinese family.
Originality/value
The paper analyzes the value of genealogical research as a documentary source for population history, life expectancy in a clan, marriages and family connections, as well as lineage organizations and inter‐lineage relations.
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Shijie Dai, Shida Li, Wenbin Ji, Ruiqin Wang and Shuyuan Liu
Considering the response lag and viscous slip oscillation of the system caused by cylinder piston friction during automatic polishing of aero-engine blades by a robotic pneumatic…
Abstract
Purpose
Considering the response lag and viscous slip oscillation of the system caused by cylinder piston friction during automatic polishing of aero-engine blades by a robotic pneumatic end-effector, the purpose of this study is to propose a constant force control method with adaptive friction compensation.
Design/methodology/approach
First, the mathematical model of the pneumatic end-effector is established based on the continuous LuGre model, and the static parameters of the LuGre model are identified to verify the necessity of friction compensation. Second, aiming at the problems of difficult identification of dynamic parameters and unmeasurable internal states in the LuGre model, the parameter adaptive law and friction state observer are designed to estimate these parameters online. Finally, an adaptive friction compensation backstepping controller is designed to improve the response speed and polishing force control accuracy of the system.
Findings
Simulation and experimental results show that, compared with proportion integration differentiation, extended state observer-based active disturbance rejection controller and integral sliding mode controller, the proposed method can quickly and effectively suppress the polishing force fluctuation caused by nonlinear friction and significantly improve the blade quality.
Originality/value
The pneumatic force control method combining backstepping control with the friction adaptive compensation based on LuGre friction model is studied, which effectively suppresses the fluctuation of normal polishing force.
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Keywords
Jun Sun, Xiande Wu, Shijie Zhang, Fengzhi Guo and Ting Song
The purpose of this paper is to propose an adaptive robust controller for coupled attitude and orbit control of rigid spacecraft based on dual quaternion in the presence of…
Abstract
Purpose
The purpose of this paper is to propose an adaptive robust controller for coupled attitude and orbit control of rigid spacecraft based on dual quaternion in the presence of external disturbances and model uncertainties.
Design/methodology/approach
First, based on dual quaternion, a theoretical model of the relative motion for rigid spacecraft is introduced. Then, an adaptive robust controller which can realize coordinated control of attitude and orbit is designed in the existence of external disturbances and model uncertainties.
Findings
This paper takes advantage of the Lyapunov function which can guarantee the asymptotic stabilization of the whole system in the existence of parameters uncertainties. Simulation results show that the proposed controller is feasible and effective.
Originality/value
This paper proposes a coupled attitude and orbit adaptive robust controller based on dual quaternion. Simulation results demonstrate that the proposed controller can achieve higher control performance in the presence of parameters uncertainties.