The automobile industry has been searching for vehicles that use less energy and emit fewer pollutants, which has resulted in a high demand for fuel-efficient vehicles. Because of their higher strength-to-weight ratio...The automobile industry has been searching for vehicles that use less energy and emit fewer pollutants, which has resulted in a high demand for fuel-efficient vehicles. Because of their higher strength-to-weight ratio compared to traditional steel, using fiber-reinforcement composite materials in automobile bodies has emerged as the most effective strategy for improving fuel efficiency while maintaining safety standards. This research paper examined the utilization of fiber-reinforced composite materials in car bodies to meet the increasing consumer demand for fuel-efficient and eco-friendly vehicles. It particularly focused on a carbon-aramid fiber-reinforced composite impact beam for passenger car side door impact protection. Despite the encouraging prospects of the carbon-aramid fiber-reinforced beam, the research uncovered substantial defects in the fabrication process, resulting in diminished load-bearing capacity and energy absorption. As a result, the beam was un-successful in three-point bending tests. This was accomplished by using an I cross-section design with varying thickness because of the higher area moment of inertia. Vacuum-assisted resin transfer molding (VARTM) manufacturing process was used and the finished beam underwent to three-point bending tests.展开更多
矢量软件在绘制产品及工程视图时会出现数据不够准确,参数化控制偏弱等情况,另一方面专业的CAD制图软件又让普通设计师难以下手。基于Adobe Illustrator平台上的Hot Door CADtools插件在这些的问题中找到了平衡点,它能既能够像专业的CA...矢量软件在绘制产品及工程视图时会出现数据不够准确,参数化控制偏弱等情况,另一方面专业的CAD制图软件又让普通设计师难以下手。基于Adobe Illustrator平台上的Hot Door CADtools插件在这些的问题中找到了平衡点,它能既能够像专业的CAD软件一样为图形标注提供准确的尺寸,同时又让CAD制图变得亲切和富有人性化。展开更多
The study profiles and explains the significant changes that have taken place in China's spatial development patterns since the inception of its economic reform and opening two decades ago. Principal component an...The study profiles and explains the significant changes that have taken place in China's spatial development patterns since the inception of its economic reform and opening two decades ago. Principal component analysis is used to delineate spatial patterns. The analyses show that prior to the reform China's spatial development pattern was characterized by the dominance of the three municipalities and the Northeast, as well as by both the coast-interior and the north-south disparities. Northern provinces were generally more industrialized and economically powerful than the southern ones. After two decades of reform, regional development has become multi-centered with South China, the Yangtze Delta and the Beijing-Tianjin area being the three most important regions of the country. The coastal provinces as a whole rose to prominence on China's economic map while the Northeast has diminished its clout. The coast-interior gap not only remains but may have widened. The north-south disparity also still exists but there has been a role reversal with the south now in the lead position. Virtually all inland provinces now find themselves at or near the low end of the development spectrum. We argue that the major reason for the recent shifts in Chinese space economy is the spatially differentiated economic growth resulted from the reform and open door policy and from the new, uneven development strategy adopted by the Chinese government. The paper discusses four specific factors that have reshaped China's spatial development patterns.展开更多
The metro door system is one of the high failure rate subsystems of metro trains. The Failure Mode, Effects and Criticality Analysis (FMECA) method is applied to analyze the reliability of metro door system in this pa...The metro door system is one of the high failure rate subsystems of metro trains. The Failure Mode, Effects and Criticality Analysis (FMECA) method is applied to analyze the reliability of metro door system in this paper. Firstly, failure components of the door are statistically analyzed, and the major failure components are determined. Secondly, failures are classified according to their impacts on operation, and methods of calculating failure mode criticality and the related coefficients are illustrated. Finally, the FMECA is detailed in the selected 12 failure modes, and the failure modes are discovered that they have the most significant effect on metro door system. The obtained results can be used for optimal design and maintenance of the metro door system.展开更多
Current practice in analysis and design of blast doors subjected to blast loading considers only simple boundary conditions and material properties. The boundary conditions and material properties, in fact, have consi...Current practice in analysis and design of blast doors subjected to blast loading considers only simple boundary conditions and material properties. The boundary conditions and material properties, in fact, have considerable influence on the response of blast doors subjected to blast loading. In this paper, the dynamic responses of a reinforced concrete arched blast door under blast loading were analyzed by the finite element program ABAQUS, combined with a previously developed elasto-viscoplastic rate-sensitive material model. And the effect of the surrounding rock mass and contact effect of the doorframe were also taken into account in the simulation. It is demonstrated that the strain-rate effect has considerable influence on the response of reinforced concrete blast door subjected to blast loading and must be taken into account in the analysis.展开更多
A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless s...A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless structure of the forcer to improve the stability of the thrust. The influence of two major dimensions, the pitch and radius of the permanent magnet (PM), on magnetic field was studied and the best values were given by the finite element analysis (FEA). The magnetic field, back EMF and thrust of the motor were analyzed and the PM size was optimized to reduce the harmonic components of the magnetic field and improve the performance of the motor. Predicted results are validated by the experiment. It is shown that the performance of the motor and the novel elevator door system is satisfying.展开更多
A method for optimizing automotive doors under multiple criteria involving the side impact, stiffness, natural frequency, and structure weight is presented. Metamodeling technique is employed to construct approximatio...A method for optimizing automotive doors under multiple criteria involving the side impact, stiffness, natural frequency, and structure weight is presented. Metamodeling technique is employed to construct approximations to replace the high computational simulation models. The approximating functions for stiffness and natural frequency are constructed using Taylor series approximation. Three popular approximation techniques,i.e.polynomial response surface (PRS), stepwise regression (SR), and Kriging are studied on their accuracy in the construction of side impact functions. Uniform design is employed to sample the design space of the door impact analysis. The optimization problem is solved by a multi-objective genetic algorithm. It is found that SR technique is superior to PRS and Kriging techniques in terms of accuracy in this study. The numerical results demonstrate that the method successfully generates a well-spread Pareto optimal set. From this Pareto optimal set, decision makers can select the most suitable design according to the vehicle program and its application.展开更多
The interfacial status of the steel-aluminum solid to liquid bonding plates (their steel plate surfaces were or were not immersed in flux aqueous solution) were measured by using SEM (Scanning Electron Microscope) and...The interfacial status of the steel-aluminum solid to liquid bonding plates (their steel plate surfaces were or were not immersed in flux aqueous solution) were measured by using SEM (Scanning Electron Microscope) and X-ray diffraction . The results showed that the layer of flux (the minimum thickness was 15 μm on the steel plate surface) could protect the steel plate surface from oxidizing effectively at high temperature in solid to liquid bonding. The melt temperatUre of the flux should be lower than 580 ℃ so that it could be melted and removed completely. No. 1 flux (patent product made by the author) made up of halogeindes could also force liquid aluminum to infiltrate into steel plate surface and thus the interfacial shear strength of the bonding plate was rather large.展开更多
As one of the main reasons causing leakage heat load in a refrigerator,mass and heat transfer through refrigerator door seal is of great importance to be studied.In this paper,a model is presented for numerical simula...As one of the main reasons causing leakage heat load in a refrigerator,mass and heat transfer through refrigerator door seal is of great importance to be studied.In this paper,a model is presented for numerical simulation of mass and heat transfer process through refrigerator door seal,and an experiment apparatus is designed and set up as well for comparison.A two-dimensional model and tracer gas method are used in simulation and experiment,respectively.It can be found that the relative deviations of air infiltration rate between the simulated results and experimental results were less than 1%,and the temperature difference errors at two special points of the door seal were less than 2.03℃.In conclusion,the simulated results are in good agreement with the experimental results.This paper initially sets up a model that can accurately simulate the heat and mass transfer through the refrigerator door seal,and the model can be used in refrigerator door seal optimization research in the follow-up study.展开更多
A new type of environmentally friendly lube additive-amide type modified rapeseed oil was synthesized and characterized by infrared spectrum. Its effect on the friction and wear behavior of steel-steel and steel-alumi...A new type of environmentally friendly lube additive-amide type modified rapeseed oil was synthesized and characterized by infrared spectrum. Its effect on the friction and wear behavior of steel-steel and steel-aluminum alloy systems were investigated with a four-ball machine and an Optimol SRV friction and wear tester respectively.The morphographies of the worn surfaces were analyzed by means of scanning electron microscopy(SEM). The worn surfaces of the 2024Al alloy block were analyzed by means of X-ray photoelectron spectroscopy(XPS). The results show that the modified rapeseed oil as additives can obviously decrease the wear rate and friction coefficient of steel pair and steel-aluminum frictional pair. Its lubrication mechanism is inferred that a high strength complex protection films form on the worn surface of the Al alloy due to the adsorption or tribochemistry reaction of a long chain additive molecule and high reaction activity of N element.展开更多
文摘The automobile industry has been searching for vehicles that use less energy and emit fewer pollutants, which has resulted in a high demand for fuel-efficient vehicles. Because of their higher strength-to-weight ratio compared to traditional steel, using fiber-reinforcement composite materials in automobile bodies has emerged as the most effective strategy for improving fuel efficiency while maintaining safety standards. This research paper examined the utilization of fiber-reinforced composite materials in car bodies to meet the increasing consumer demand for fuel-efficient and eco-friendly vehicles. It particularly focused on a carbon-aramid fiber-reinforced composite impact beam for passenger car side door impact protection. Despite the encouraging prospects of the carbon-aramid fiber-reinforced beam, the research uncovered substantial defects in the fabrication process, resulting in diminished load-bearing capacity and energy absorption. As a result, the beam was un-successful in three-point bending tests. This was accomplished by using an I cross-section design with varying thickness because of the higher area moment of inertia. Vacuum-assisted resin transfer molding (VARTM) manufacturing process was used and the finished beam underwent to three-point bending tests.
文摘矢量软件在绘制产品及工程视图时会出现数据不够准确,参数化控制偏弱等情况,另一方面专业的CAD制图软件又让普通设计师难以下手。基于Adobe Illustrator平台上的Hot Door CADtools插件在这些的问题中找到了平衡点,它能既能够像专业的CAD软件一样为图形标注提供准确的尺寸,同时又让CAD制图变得亲切和富有人性化。
文摘The study profiles and explains the significant changes that have taken place in China's spatial development patterns since the inception of its economic reform and opening two decades ago. Principal component analysis is used to delineate spatial patterns. The analyses show that prior to the reform China's spatial development pattern was characterized by the dominance of the three municipalities and the Northeast, as well as by both the coast-interior and the north-south disparities. Northern provinces were generally more industrialized and economically powerful than the southern ones. After two decades of reform, regional development has become multi-centered with South China, the Yangtze Delta and the Beijing-Tianjin area being the three most important regions of the country. The coastal provinces as a whole rose to prominence on China's economic map while the Northeast has diminished its clout. The coast-interior gap not only remains but may have widened. The north-south disparity also still exists but there has been a role reversal with the south now in the lead position. Virtually all inland provinces now find themselves at or near the low end of the development spectrum. We argue that the major reason for the recent shifts in Chinese space economy is the spatially differentiated economic growth resulted from the reform and open door policy and from the new, uneven development strategy adopted by the Chinese government. The paper discusses four specific factors that have reshaped China's spatial development patterns.
文摘The metro door system is one of the high failure rate subsystems of metro trains. The Failure Mode, Effects and Criticality Analysis (FMECA) method is applied to analyze the reliability of metro door system in this paper. Firstly, failure components of the door are statistically analyzed, and the major failure components are determined. Secondly, failures are classified according to their impacts on operation, and methods of calculating failure mode criticality and the related coefficients are illustrated. Finally, the FMECA is detailed in the selected 12 failure modes, and the failure modes are discovered that they have the most significant effect on metro door system. The obtained results can be used for optimal design and maintenance of the metro door system.
基金Supported by National Natural Science Foundation of China(No.50525825)
文摘Current practice in analysis and design of blast doors subjected to blast loading considers only simple boundary conditions and material properties. The boundary conditions and material properties, in fact, have considerable influence on the response of blast doors subjected to blast loading. In this paper, the dynamic responses of a reinforced concrete arched blast door under blast loading were analyzed by the finite element program ABAQUS, combined with a previously developed elasto-viscoplastic rate-sensitive material model. And the effect of the surrounding rock mass and contact effect of the doorframe were also taken into account in the simulation. It is demonstrated that the strain-rate effect has considerable influence on the response of reinforced concrete blast door subjected to blast loading and must be taken into account in the analysis.
基金Project (No. 50607016) supported by the National Natural ScienceFoundation of China
文摘A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless structure of the forcer to improve the stability of the thrust. The influence of two major dimensions, the pitch and radius of the permanent magnet (PM), on magnetic field was studied and the best values were given by the finite element analysis (FEA). The magnetic field, back EMF and thrust of the motor were analyzed and the PM size was optimized to reduce the harmonic components of the magnetic field and improve the performance of the motor. Predicted results are validated by the experiment. It is shown that the performance of the motor and the novel elevator door system is satisfying.
基金Supported by National"863"Program of China (No.2006AA04Z127) .
文摘A method for optimizing automotive doors under multiple criteria involving the side impact, stiffness, natural frequency, and structure weight is presented. Metamodeling technique is employed to construct approximations to replace the high computational simulation models. The approximating functions for stiffness and natural frequency are constructed using Taylor series approximation. Three popular approximation techniques,i.e.polynomial response surface (PRS), stepwise regression (SR), and Kriging are studied on their accuracy in the construction of side impact functions. Uniform design is employed to sample the design space of the door impact analysis. The optimization problem is solved by a multi-objective genetic algorithm. It is found that SR technique is superior to PRS and Kriging techniques in terms of accuracy in this study. The numerical results demonstrate that the method successfully generates a well-spread Pareto optimal set. From this Pareto optimal set, decision makers can select the most suitable design according to the vehicle program and its application.
文摘The interfacial status of the steel-aluminum solid to liquid bonding plates (their steel plate surfaces were or were not immersed in flux aqueous solution) were measured by using SEM (Scanning Electron Microscope) and X-ray diffraction . The results showed that the layer of flux (the minimum thickness was 15 μm on the steel plate surface) could protect the steel plate surface from oxidizing effectively at high temperature in solid to liquid bonding. The melt temperatUre of the flux should be lower than 580 ℃ so that it could be melted and removed completely. No. 1 flux (patent product made by the author) made up of halogeindes could also force liquid aluminum to infiltrate into steel plate surface and thus the interfacial shear strength of the bonding plate was rather large.
基金Supported by the National Science Fund for Distinguished Young Scholar(51525604)111 project B16038
文摘As one of the main reasons causing leakage heat load in a refrigerator,mass and heat transfer through refrigerator door seal is of great importance to be studied.In this paper,a model is presented for numerical simulation of mass and heat transfer process through refrigerator door seal,and an experiment apparatus is designed and set up as well for comparison.A two-dimensional model and tracer gas method are used in simulation and experiment,respectively.It can be found that the relative deviations of air infiltration rate between the simulated results and experimental results were less than 1%,and the temperature difference errors at two special points of the door seal were less than 2.03℃.In conclusion,the simulated results are in good agreement with the experimental results.This paper initially sets up a model that can accurately simulate the heat and mass transfer through the refrigerator door seal,and the model can be used in refrigerator door seal optimization research in the follow-up study.
基金Project supported by the National Natural Science Foundation of China
文摘A new type of environmentally friendly lube additive-amide type modified rapeseed oil was synthesized and characterized by infrared spectrum. Its effect on the friction and wear behavior of steel-steel and steel-aluminum alloy systems were investigated with a four-ball machine and an Optimol SRV friction and wear tester respectively.The morphographies of the worn surfaces were analyzed by means of scanning electron microscopy(SEM). The worn surfaces of the 2024Al alloy block were analyzed by means of X-ray photoelectron spectroscopy(XPS). The results show that the modified rapeseed oil as additives can obviously decrease the wear rate and friction coefficient of steel pair and steel-aluminum frictional pair. Its lubrication mechanism is inferred that a high strength complex protection films form on the worn surface of the Al alloy due to the adsorption or tribochemistry reaction of a long chain additive molecule and high reaction activity of N element.
