China's economic growth and economic development has entered a new stage,and the optimization and upgrading of industrial structure is the core driving force for China to achieve high-quality economic development ...China's economic growth and economic development has entered a new stage,and the optimization and upgrading of industrial structure is the core driving force for China to achieve high-quality economic development during the"14 th Five-Year Plan"period.Property tax has a conductive effect on the upgrading of industrial structure.Therefore,from the perspective of property tax and industrial structure adjustment and the relationship between them,this study summarizes the relevant research of domestic and foreign scholars.On the basis of the research,the paper puts forward some relevant policy suggestions on improving China's property tax and promoting the optimization and upgrading of China's industrial structure.展开更多
With the rapid development of the social economy,science and technology continue to upgrade and optimize,ushering in the digital era,which provides technical support for industrial innovation and development across al...With the rapid development of the social economy,science and technology continue to upgrade and optimize,ushering in the digital era,which provides technical support for industrial innovation and development across all sectors.At this stage,vigorously developing the digital economy has gradually become the only means to optimize and upgrade the industrial structure.Therefore,local leaders and relevant departments need to enhance the importance of constructing the digital economy,enabling the local industrial structure to be optimized and upgraded under the impetus of the digital economy,ultimately promoting overall economic high-quality development.To this end,this paper,combined with existing research results,first elaborates on the positive impact of the digital economy on the optimization and upgrading of the industrial structure.It then analyzes the challenges hindering the process of industrial structure optimization and upgrading and proposes practical pathways to address them,benefiting relevant stakeholders.展开更多
Based on the 16 central cities＇ Panel Data in Yangtze River Delta, location quotient index is used in this paper to measure and analyze the current cluster situation of producer services in Yangtze River Delta, fixed...Based on the 16 central cities＇ Panel Data in Yangtze River Delta, location quotient index is used in this paper to measure and analyze the current cluster situation of producer services in Yangtze River Delta, fixed effects model of Panel Data model is also used in this paper, and the industrial structure is taken as the dependent variable, while the core explanatory variables is the degree of producer services＇ cluster development, which is calculated by location quotient, moreover, three control variables introduced in this paper and they are technology advantage, education level and R＆D spending, and the mentioned above is to empirically study the impacts of producer services＇ cluster development to the regional industrial structure. As a result, producer services＇ cluster development has a significant positive role in promoting the regional industrial structure optimization and upgrading, though the extent is not yet a big push and is still to be further strengthened. In this paper, it has provided a strong evidence that under China＇ s new normal economy, producer services is badly needed to promote regional industrial structure, and finally it makes specific suggestions based on the current cluster situation of producer services in Yangtze River Delta.展开更多
Multifunctional structures(MFSs)integrate diverse functions to achieve superior properties.However,conventional design and manufacturing methods—which generally lack quality control and largely depend on complex equi...Multifunctional structures(MFSs)integrate diverse functions to achieve superior properties.However,conventional design and manufacturing methods—which generally lack quality control and largely depend on complex equipment with multiple stations to achieve the integration of distinct materials and devices—are unable to satisfy the requirements of MFS applications in emerging industries such as aerospace engineering.Motivated by the concept of design for manufacturing,we adopt a layer regulation method with an established optimization model to design typical MFSs with load-bearing,electric,heat-conduction,and radiation-shielding functions.A high-temperature in situ additive manufacturing(AM)technology is developed to print various metallic wires or carbon fiber-reinforced high-meltingpoint polyetheretherketone(PEEK)composites.It is found that the MFS,despite its low mass,exceeds the stiffness of the PEEK substrate by 21.5%.The embedded electrics remain functional after the elastic deformation stage.Compared with those of the PEEK substrate,the equivalent thermal conductivity of the MFS beneath the central heat source area is enhanced by 568.0%,and the radiation shielding is improved by 27.9%.Moreover,a satellite prototype with diverse MFSs is rapidly constructed as an illustration.This work provides a systematic approach for high-performance design and advanced manufacturing,which exhibits considerable prospects for both the function expansion and performance enhancement of industrial equipment.展开更多
In the present study,we propose to integrate the bilateral filter into the Shepard-interpolation-based method for the optimization of composite structures.The bilateral filter is used to avoid defects in the structure...In the present study,we propose to integrate the bilateral filter into the Shepard-interpolation-based method for the optimization of composite structures.The bilateral filter is used to avoid defects in the structure that may arise due to the gap/overlap of adjacent fiber tows or excessive curvature of fiber tows.According to the bilateral filter,sensitivities at design points in the filter area are smoothed by both domain filtering and range filtering.Then,the filtered sensitivities are used to update the design variables.Through several numerical examples,the effectiveness of the method was verified.展开更多
This paper introduces an efficient holistic approach to the design optimization of lightweight structures of braided fiber-reinforced plastic material. The approach aims to mitigate the paradox of making design decisi...This paper introduces an efficient holistic approach to the design optimization of lightweight structures of braided fiber-reinforced plastic material. The approach aims to mitigate the paradox of making design decisions at early development phases, when necessary information is incomplete or lacking detail so as to properly make these decisions. However, expert knowledge is available and though it is imprecise in nature, it can compensate to create useful models. Manufacturing effort for the braiding process has been described by information accumulated via interviews with braiding experts. This information is then modelled using the soft-computing approach by fuzzy-rule-based systems. The resulting models can further be efficiently integrated into the structural design optimization process. A multidisciplinary design optimization is facilitated considering several aspects including manufacturing effort and structural mechanics, which can be used in early design phases leading to more holistic designing and, thereby, unlocking lightweight and cost-reducing potentials. Benefits of this method, including viability and ease of implementation, are proven by investigations on two academic test problems before advancing to the challenging automotive engineering design problem of the roadster A-pillar.展开更多
Additive manufacturing(AM)has made significant progress in recent years and has been successfully applied in various fields owing to its ability to manufacture complex geometries.This method efficiently expands the de...Additive manufacturing(AM)has made significant progress in recent years and has been successfully applied in various fields owing to its ability to manufacture complex geometries.This method efficiently expands the design space,allowing for the creation of products with better performance than ever before.With the emergence of new manufacturing technologies,new design methods are required to efficiently utilize the expanded design space.Therefore,topology optimization methods have attracted the attention of researchers because of their ability to generate new and optimized designs without requiring prior experience.The combination of AM and topology optimization has proven to be a powerful tool for structural innovation in design and manufacturing.However,it is important to note that AM does not eliminate all manufacturing restrictions but instead replaces them with a different set of design considerations that designers must consider for the successful implementation of these technologies.This has motivated research on topology optimization methods that incorporate manufacturable constraints for AM structures.In this paper,we present a survey of the latest studies in this research area,with a particular focus on developments in China.Additionally,we discuss the existing research gaps and future development trends.展开更多
Based on reform of the supply front,this paper analyzes the main constraints on China's current structure of agricultural products,including irrational allocation of resources between agricultural products,promine...Based on reform of the supply front,this paper analyzes the main constraints on China's current structure of agricultural products,including irrational allocation of resources between agricultural products,prominent problems concerning agricultural product quality and safety,disconnection between market demand and agricultural product R&D,and low processing capacity of agricultural products. Based on summing up the experience of the countries with developed agriculture,this paper proposes the path and mechanism for the optimization of structure of agricultural products in China: optimizing resource allocation of agricultural products; improving the quality of agricultural products; enhancing the R&D capacity of agricultural enterprises; promoting the processing and conversion capacity of agricultural products; perfecting the policy support and subsidy mode.展开更多
In order to solve the problem of substantial computational resources of lattice structure during optimization, a local relative density mapping(LRDM) method is proposed. The proposed method uses solid isotropic micros...In order to solve the problem of substantial computational resources of lattice structure during optimization, a local relative density mapping(LRDM) method is proposed. The proposed method uses solid isotropic microstructures with penalization to optimize a model at the macroscopic scale. The local relative density information is obtained from the topology optimization result. The contour lines of an optimized model are extracted using a density contour approach, and the triangular mesh is generated using a mesh generator. A local mapping relationship between the elements’ relative density and the struts’ relative cross?sectional area is established to automatically determine the diameter of each individual strut in the lattice structures. The proposed LRDM method can be applied to local finite element meshes and local density elements, but it is also suitable for global ones. In addition, some cases are con?sidered in order to test the e ectiveness of the LRDM method. The results show that the solution time of the LRDM is lower than the RDM method by approximately 50%. The proposed method provides instructions for the design of more complex lattice structures.展开更多
Owing to their excellent performance and large design space,curvilinear fiber-reinforced composite structures have gained considerable attention in engineering fields such as aerospace and automobile.In addition to th...Owing to their excellent performance and large design space,curvilinear fiber-reinforced composite structures have gained considerable attention in engineering fields such as aerospace and automobile.In addition to the stiffness and strength of such structures,their stability also needs to be taken into account in the design.This study proposes a level-set-based optimization framework for maximizing the buckling load of curvilinear fiber-reinforced composite structures.In the proposed method,the contours of the level set function are used to represent fiber paths.For a composite laminate with a certain number of layers,one level set function is defined by radial basis functions and expansion coefficients for each layer.Furthermore,the fiber angle at an arbitrary point is the tangent orientation of the contour through this point.In the finite element of buckling,the stiffness and geometry matrices of an element are related to the fiber angle at the element centroid.This study considers the parallelism constraint for fiber paths.With the sensitivity calculation of the objective and constraint functions,the method of moving asymptotes is utilized to iteratively update all the expansion coefficients regarded as design variables.Two numerical examples under different boundary conditions are given to validate the proposed approach.Results show that the optimized curved fiber paths tend to be parallel and equidistant regardless of whether the composite laminates contain holes or not.Meanwhile,the buckling resistance of the final design is significantly improved.展开更多
Multi-photon polymerization is a well-established,yet actively developing,additive manufacturing technique for 3D printing on the micro/nanoscale.Like all additive manufacturing techniques,determining the process para...Multi-photon polymerization is a well-established,yet actively developing,additive manufacturing technique for 3D printing on the micro/nanoscale.Like all additive manufacturing techniques,determining the process parameters necessary to achieve dimensional accuracy for a structure 3D printed using this method is not always straightforward and can require time-consuming experimentation.In this work,an active machine learning based framework is presented for determining optimal process parameters for the recently developed,high-speed,layer-by-layer continuous projection 3D printing process.The proposed active learning framework uses Bayesian optimization to inform optimal experimentation in order to adaptively collect the most informative data for effective training of a Gaussian-process-regression-based machine learning model.This model then serves as a surrogate for the manufacturing process:predicting optimal process parameters for achieving a target geometry,e.g,the 2D geometry of each printed layer.Three representative 2D shapes at three different scales are used as test cases.In each case,the active learning framework improves the geometric accuracy,with drastic reductions of the errors to within the measurement accuracy in just four iterations of the Bayesian optimization using only a few hundred of total training data.The case studies indicate that the active learning framework developed in this work can be broadly applied to other additive manufacturing processes to increase accuracy with significantly reduced experimental data collection effortforoptimization.展开更多
基金Supported by 2023 Jiangxi Provincial Innovation and Entrepreneurship Training Project(202310414021).
文摘China's economic growth and economic development has entered a new stage,and the optimization and upgrading of industrial structure is the core driving force for China to achieve high-quality economic development during the"14 th Five-Year Plan"period.Property tax has a conductive effect on the upgrading of industrial structure.Therefore,from the perspective of property tax and industrial structure adjustment and the relationship between them,this study summarizes the relevant research of domestic and foreign scholars.On the basis of the research,the paper puts forward some relevant policy suggestions on improving China's property tax and promoting the optimization and upgrading of China's industrial structure.
文摘With the rapid development of the social economy,science and technology continue to upgrade and optimize,ushering in the digital era,which provides technical support for industrial innovation and development across all sectors.At this stage,vigorously developing the digital economy has gradually become the only means to optimize and upgrade the industrial structure.Therefore,local leaders and relevant departments need to enhance the importance of constructing the digital economy,enabling the local industrial structure to be optimized and upgraded under the impetus of the digital economy,ultimately promoting overall economic high-quality development.To this end,this paper,combined with existing research results,first elaborates on the positive impact of the digital economy on the optimization and upgrading of the industrial structure.It then analyzes the challenges hindering the process of industrial structure optimization and upgrading and proposes practical pathways to address them,benefiting relevant stakeholders.
文摘Based on the 16 central cities＇ Panel Data in Yangtze River Delta, location quotient index is used in this paper to measure and analyze the current cluster situation of producer services in Yangtze River Delta, fixed effects model of Panel Data model is also used in this paper, and the industrial structure is taken as the dependent variable, while the core explanatory variables is the degree of producer services＇ cluster development, which is calculated by location quotient, moreover, three control variables introduced in this paper and they are technology advantage, education level and R＆D spending, and the mentioned above is to empirically study the impacts of producer services＇ cluster development to the regional industrial structure. As a result, producer services＇ cluster development has a significant positive role in promoting the regional industrial structure optimization and upgrading, though the extent is not yet a big push and is still to be further strengthened. In this paper, it has provided a strong evidence that under China＇ s new normal economy, producer services is badly needed to promote regional industrial structure, and finally it makes specific suggestions based on the current cluster situation of producer services in Yangtze River Delta.
基金supported by the National Natural Science Foundation of China(51822503,U20A20297,and 51975142)Key-Area Research and Development Program of Guangdong Province,China(2020B090923003)。
文摘Multifunctional structures(MFSs)integrate diverse functions to achieve superior properties.However,conventional design and manufacturing methods—which generally lack quality control and largely depend on complex equipment with multiple stations to achieve the integration of distinct materials and devices—are unable to satisfy the requirements of MFS applications in emerging industries such as aerospace engineering.Motivated by the concept of design for manufacturing,we adopt a layer regulation method with an established optimization model to design typical MFSs with load-bearing,electric,heat-conduction,and radiation-shielding functions.A high-temperature in situ additive manufacturing(AM)technology is developed to print various metallic wires or carbon fiber-reinforced high-meltingpoint polyetheretherketone(PEEK)composites.It is found that the MFS,despite its low mass,exceeds the stiffness of the PEEK substrate by 21.5%.The embedded electrics remain functional after the elastic deformation stage.Compared with those of the PEEK substrate,the equivalent thermal conductivity of the MFS beneath the central heat source area is enhanced by 568.0%,and the radiation shielding is improved by 27.9%.Moreover,a satellite prototype with diverse MFSs is rapidly constructed as an illustration.This work provides a systematic approach for high-performance design and advanced manufacturing,which exhibits considerable prospects for both the function expansion and performance enhancement of industrial equipment.
基金This research work was supported by the National Natural Science Foundation of China(Grant No.51975227)the Natural Science Foundation for Distinguished Young Scholars of Hubei Province,China(Grant No.2017CFA044).
文摘In the present study,we propose to integrate the bilateral filter into the Shepard-interpolation-based method for the optimization of composite structures.The bilateral filter is used to avoid defects in the structure that may arise due to the gap/overlap of adjacent fiber tows or excessive curvature of fiber tows.According to the bilateral filter,sensitivities at design points in the filter area are smoothed by both domain filtering and range filtering.Then,the filtered sensitivities are used to update the design variables.Through several numerical examples,the effectiveness of the method was verified.
文摘This paper introduces an efficient holistic approach to the design optimization of lightweight structures of braided fiber-reinforced plastic material. The approach aims to mitigate the paradox of making design decisions at early development phases, when necessary information is incomplete or lacking detail so as to properly make these decisions. However, expert knowledge is available and though it is imprecise in nature, it can compensate to create useful models. Manufacturing effort for the braiding process has been described by information accumulated via interviews with braiding experts. This information is then modelled using the soft-computing approach by fuzzy-rule-based systems. The resulting models can further be efficiently integrated into the structural design optimization process. A multidisciplinary design optimization is facilitated considering several aspects including manufacturing effort and structural mechanics, which can be used in early design phases leading to more holistic designing and, thereby, unlocking lightweight and cost-reducing potentials. Benefits of this method, including viability and ease of implementation, are proven by investigations on two academic test problems before advancing to the challenging automotive engineering design problem of the roadster A-pillar.
基金supported by National Natural Science Foundation of China(Grant Nos.12272076,U2341232,11332004,and U1808215)the 111 Project of China(Grant No.B14013).
文摘Additive manufacturing(AM)has made significant progress in recent years and has been successfully applied in various fields owing to its ability to manufacture complex geometries.This method efficiently expands the design space,allowing for the creation of products with better performance than ever before.With the emergence of new manufacturing technologies,new design methods are required to efficiently utilize the expanded design space.Therefore,topology optimization methods have attracted the attention of researchers because of their ability to generate new and optimized designs without requiring prior experience.The combination of AM and topology optimization has proven to be a powerful tool for structural innovation in design and manufacturing.However,it is important to note that AM does not eliminate all manufacturing restrictions but instead replaces them with a different set of design considerations that designers must consider for the successful implementation of these technologies.This has motivated research on topology optimization methods that incorporate manufacturable constraints for AM structures.In this paper,we present a survey of the latest studies in this research area,with a particular focus on developments in China.Additionally,we discuss the existing research gaps and future development trends.
基金Supported by National Natural Science Foundation(71473205)Doctoral Fund Project of Southwest University(SWU1209338)
文摘Based on reform of the supply front,this paper analyzes the main constraints on China's current structure of agricultural products,including irrational allocation of resources between agricultural products,prominent problems concerning agricultural product quality and safety,disconnection between market demand and agricultural product R&D,and low processing capacity of agricultural products. Based on summing up the experience of the countries with developed agriculture,this paper proposes the path and mechanism for the optimization of structure of agricultural products in China: optimizing resource allocation of agricultural products; improving the quality of agricultural products; enhancing the R&D capacity of agricultural enterprises; promoting the processing and conversion capacity of agricultural products; perfecting the policy support and subsidy mode.
基金National Hi-tech Research and Development Program of China(863 Program,Grant No.2015BAF04B00)China Aerospace Science and Technology Corporation Program of China(CASIC Program,Grant No.461717)
文摘In order to solve the problem of substantial computational resources of lattice structure during optimization, a local relative density mapping(LRDM) method is proposed. The proposed method uses solid isotropic microstructures with penalization to optimize a model at the macroscopic scale. The local relative density information is obtained from the topology optimization result. The contour lines of an optimized model are extracted using a density contour approach, and the triangular mesh is generated using a mesh generator. A local mapping relationship between the elements’ relative density and the struts’ relative cross?sectional area is established to automatically determine the diameter of each individual strut in the lattice structures. The proposed LRDM method can be applied to local finite element meshes and local density elements, but it is also suitable for global ones. In addition, some cases are con?sidered in order to test the e ectiveness of the LRDM method. The results show that the solution time of the LRDM is lower than the RDM method by approximately 50%. The proposed method provides instructions for the design of more complex lattice structures.
基金supported by the National Natural Science Foundation of China(Grant Nos.51975227 and 12272144)。
文摘Owing to their excellent performance and large design space,curvilinear fiber-reinforced composite structures have gained considerable attention in engineering fields such as aerospace and automobile.In addition to the stiffness and strength of such structures,their stability also needs to be taken into account in the design.This study proposes a level-set-based optimization framework for maximizing the buckling load of curvilinear fiber-reinforced composite structures.In the proposed method,the contours of the level set function are used to represent fiber paths.For a composite laminate with a certain number of layers,one level set function is defined by radial basis functions and expansion coefficients for each layer.Furthermore,the fiber angle at an arbitrary point is the tangent orientation of the contour through this point.In the finite element of buckling,the stiffness and geometry matrices of an element are related to the fiber angle at the element centroid.This study considers the parallelism constraint for fiber paths.With the sensitivity calculation of the objective and constraint functions,the method of moving asymptotes is utilized to iteratively update all the expansion coefficients regarded as design variables.Two numerical examples under different boundary conditions are given to validate the proposed approach.Results show that the optimized curved fiber paths tend to be parallel and equidistant regardless of whether the composite laminates contain holes or not.Meanwhile,the buckling resistance of the final design is significantly improved.
基金supported by the National Science Foundation(NSF)through grant numbers CMMI-2135585 and CMMI-2229143J.EJ.acknowledges the National Science Foundation for support under the Graduate Research Fellowship Program(GRFP)under grant number DGE-1842166.
文摘Multi-photon polymerization is a well-established,yet actively developing,additive manufacturing technique for 3D printing on the micro/nanoscale.Like all additive manufacturing techniques,determining the process parameters necessary to achieve dimensional accuracy for a structure 3D printed using this method is not always straightforward and can require time-consuming experimentation.In this work,an active machine learning based framework is presented for determining optimal process parameters for the recently developed,high-speed,layer-by-layer continuous projection 3D printing process.The proposed active learning framework uses Bayesian optimization to inform optimal experimentation in order to adaptively collect the most informative data for effective training of a Gaussian-process-regression-based machine learning model.This model then serves as a surrogate for the manufacturing process:predicting optimal process parameters for achieving a target geometry,e.g,the 2D geometry of each printed layer.Three representative 2D shapes at three different scales are used as test cases.In each case,the active learning framework improves the geometric accuracy,with drastic reductions of the errors to within the measurement accuracy in just four iterations of the Bayesian optimization using only a few hundred of total training data.The case studies indicate that the active learning framework developed in this work can be broadly applied to other additive manufacturing processes to increase accuracy with significantly reduced experimental data collection effortforoptimization.
