Baocheng Liu, Jinliang Liu, Yanqian Wen, Qinglin Hu, Liang Liu and Shili Zhao
In this paper, to obtain shear and bending performance of carbon fiber-reinforced polymer (CFRP)-strengthened beams bonded by geopolymers, the effects of impregnated adhesive…
Abstract
Purpose
In this paper, to obtain shear and bending performance of carbon fiber-reinforced polymer (CFRP)-strengthened beams bonded by geopolymers, the effects of impregnated adhesive types, strengthened scheme, CFRP layer and pre-cracked width are investigated, and the performance of CFRP-strengthened beams is validated by the establishment of Finite Element Models (FEMs).
Design/methodology/approach
In this paper, static loading test and finite element analysis of epoxy-CFRP-strengthened (ECS) and geopolymer-CFRP-strengthened (GCS) were carried out, and the bearing capacity and stiffness were compared, the results show that GCS reinforced concrete (RC) beam is feasible and effective.
Findings
The bearing capacity, crack distribution and development, load–deflection curves of GCS RC beams with different pre-crack widths were investigated. The reinforcement effect of geopolymer achieves the same as epoxy, effectively improving the ultimate bearing capacity of the beam, with a maximum increase rate of 28.9%. The failure mode of CFRP is broken in the yield failure stage of GCS RC beam with reasonable strengthening form, and the utilization rate of CFRP is improved. CFRP-strengthened layers, pre-cracked widths significantly affect the mechanical properties, and deformation properties of the strengthened beams.
Originality/value
Compared with ECS RC beams, the bearing capacity and stiffness of GCS RC beams are similar to or even better, indicating that GCS RC beam is feasible and effective. It is a new method for CFRP-strengthened beams, which not only conforms to the concept of national ecological civilization construction, but also provides an economical, environmentally friendly and excellent performance solution for structural reinforcement.
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Hongfei Zhu, Xiekui Zhang and Baocheng Yu
This study aims to investigate whether the increasing robot adoption will affect employment rate and wages to contribute to the economic cycle and sustainable development in the…
Abstract
Purpose
This study aims to investigate whether the increasing robot adoption will affect employment rate and wages to contribute to the economic cycle and sustainable development in the world.
Design/methodology/approach
The authors introduce a two-way fixed effect model and ordinary least-squares (OLS) model to evaluate the influence based on relevant data of the eighteen countries with the largest robot stocks and robot densities in the world from 2006 to 2019 to test the influences and do the robustness test and endogeneity test by using empirical models.
Findings
The authors’ research findings suggest that increasing robot adoption can cause strong negative impacts on employment for both males and females in these economies. Second, the effect of robots on reducing job opportunities has penetrated different industries. It means that this negative impact of robots is comprehensive for the industry. Third, robot adoption can have a strong positive influence on wages and increase workers' incomes.
Research limitations/implications
The limitations of the study are that the influence of industrial intelligence technologies on the circular economy is diversities in different countries. Thus, this study should consider the development levels of different economies to do additional confirmatory studies.
Practical implications
This study makes out the correlations between industrial robots and the employment market from the circular economy perspective. The result proves the existence of this influence relationship, and the authors propose some suggestions to promote sustainable economic development.
Social implications
This paper addresses the activity of industrial intelligence technologies in the labor market. The employment market is an important part of the circular economy, and it will benefit social development if the government provides appropriate guidance for social investment and industrial layout.
Originality/value
This study is one of the few studies which considered the impact of industrial robots on employment and wages from the perspective of different industries, and this is very important for the circular economy in the world. The results of this paper provide an instructive reference for government policymakers and other countries to stabilize the labor market and optimize human resources for sustainable economic development.
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Yunlu Du, Yunkai Huang, Baocheng Guo, Zakarya Djelloul-Khedda, Frédéric Dubas and Hajime Igarashi
Compared with the time-consuming numerical method and the complex lumped parameter thermal network method to solve the steady-state heat distribution of the permanent magnet (PM…
Abstract
Purpose
Compared with the time-consuming numerical method and the complex lumped parameter thermal network method to solve the steady-state heat distribution of the permanent magnet (PM) linear motor, there is no analytical method based on the thermal partial differential equations. This paper aims to propose a two-dimensional (2-D) analytical model for predicting the steady-state temperature distribution of PM linear motors to improve the prediction accuracy and speed up the calculation.
Design/methodology/approach
Based on the complex Fourier series theory and Cauchy’s product theorem, this paper presents for the first time a general analytical solution for 2-D temperature field in Cartesian coordinates. Then, by combining the electromagnetic field finite element model (FEM), the copper loss, iron loss and PM eddy current loss are used as the heat sources of the thermal analytical model. Finally, the solution to the temperature field is obtained by solving the system equations under boundary and interface conditions.
Findings
The analytical results are in good agreement with those from the thermal FEM, and the calculation speed is significantly faster than that of the thermal FEM.
Originality/value
The multilayer model proposed in this paper can consider heat conduction, convection and radiation. It is not only suitable for PM linear motors but also has significant application value for the thermal analysis of electromagnetic devices modeled in 2-D Cartesian coordinates.
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Zakarya Djelloul Khedda, Kamel Boughrara, Frédéric Dubas, Baocheng Guo and El Hadj Ailam
Thermal analysis of electrical machines is usually performed by using numerical methods or lumped parameter thermal networks depending on the desired accuracy. The analytical…
Abstract
Purpose
Thermal analysis of electrical machines is usually performed by using numerical methods or lumped parameter thermal networks depending on the desired accuracy. The analytical prediction of temperature distribution based on the formal resolution of thermal partial differential equations (PDEs) by the harmonic modeling technique (or the Fourier method) is uncommon in electrical machines. Therefore, this paper aims to present a two-dimensional (2D) analytical model of steady-state temperature distribution for permanent-magnet (PM) synchronous machines (PMSM) operating in generator mode.
Design/methodology/approach
The proposed model is based on the multi-layer models with the convolution theorem (i.e. Cauchy’s product theorem) by using complex Fourier’s series and the separation of variables method. This technique takes into the different thermal conductivities of the machine parts. The heat sources are determined by calculating the different power losses in the PMSM with the finite-element method (FEM).
Findings
To validate the proposed analytical model, the analytical results are compared with those obtained by thermal FEM. The comparisons show good results of the proposed model.
Originality/value
A new 2D analytical model based on the PDE in steady-state for full prediction of temperature distribution in the PMSM takes into account the heat transfer by conduction, convection and radiation.
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Wei Wang, Yi Zhang and Shuguang Chen
Influenced by factors such as fluctuations in market supply and demand and the rapid development of new technologies, manufacturing companies are facing greater challenges to…
Abstract
Purpose
Influenced by factors such as fluctuations in market supply and demand and the rapid development of new technologies, manufacturing companies are facing greater challenges to transform and upgrade. The existing relevant studies about sustainable innovation capabilities mostly focus on classification of innovation or from a static resource-based view and less on quantitative measurement from a dynamic perspective and inter-organizational relationships. This paper takes a dynamic capabilities and social capital theory, explore the concept and dimensions of sustainable innovation capabilities and then makes development of a new scale.
Design/methodology/approach
This paper uses a combination of qualitative and quantitative research methodologies to develop a measure of sustainable innovation capabilities in two studies. Grounded theory methodology is used to explore the concept definition and dimensions of sustainable innovation capabilities. Exploratory factor analysis and confirmatory factor analysis are conducted to refine and validate the factor structure, and then the authors developed the sustainable innovation capabilities scale.
Findings
The results show that sustainable innovation capabilities composed of ideation capabilities, opportunity capture capabilities, agile learning, creative inheritance and networking capabilities. The sustainable innovation capabilities that firms should possess are reflected at the firm level and inter-organizational relationship level, and the culture-specific dimension of creative inheritance reflects the influence of national and organizational culture.
Originality/value
The research reveals the internal driving force of the manufacturer's sustainable innovation capabilities, as well as the role and uniqueness embodied in the specific culture, providing a new perspective for improving the manufacturer's sustainable innovation capabilities.