Typical multidisciplinary design optimization(MDO) has gradually been proposed to balance performances of lightweight, noise, vibration and harshness(NVH) and safety for instrument panel(IP) structure in the aut...Typical multidisciplinary design optimization(MDO) has gradually been proposed to balance performances of lightweight, noise, vibration and harshness(NVH) and safety for instrument panel(IP) structure in the automotive development. Nevertheless, plastic constitutive relation of Polypropylene(PP) under different strain rates, has not been taken into consideration in current reliability-based and collaborative IP MDO design. In this paper, based on tensile test under different strain rates, the constitutive relation of Polypropylene material is studied. Impact simulation tests for head and knee bolster are carried out to meet the regulation of FMVSS 201 and FMVSS 208, respectively. NVH analysis is performed to obtain mainly the natural frequencies and corresponding mode shapes, while the crashworthiness analysis is employed to examine the crash behavior of IP structure. With the consideration of lightweight, NVH, head and knee bolster impact performance, design of experiment(DOE), response surface model(RSM), and collaborative optimization(CO) are applied to realize the determined and reliability-based optimizations, respectively. Furthermore, based on multi-objective genetic algorithm(MOGA), the optimal Pareto sets are completed to solve the multi-objective optimization(MOO) problem. The proposed research ensures the smoothness of Pareto set, enhances the ability of engineers to make a comprehensive decision about multi-objectives and choose the optimal design, and improves the quality and efficiency of MDO.展开更多
The dashboard is the most important part of the large inner decoration of cars;it should not only have enough strength and rigidity,but also have a harmonious body model which can unify the theme.Besides,it needs to r...The dashboard is the most important part of the large inner decoration of cars;it should not only have enough strength and rigidity,but also have a harmonious body model which can unify the theme.Besides,it needs to reach the goal of lightweight.In order to achieve these three goals,the car dashboard is made by engineering-plastics and adopts the technology of injection moulding.This paper introduces the keys of design and the advanced technology of large injection moulding for car dashboard.展开更多
Will ports become less important in a post-industrial period dominated by service industries?This paper examines the impact and the spillover effects of ports on city economies.The results show that ports contribute t...Will ports become less important in a post-industrial period dominated by service industries?This paper examines the impact and the spillover effects of ports on city economies.The results show that ports contribute to city economies primarily through producer and consumer services.To be specific,ports can drive the development of port-related producer services,and port spillover effects from other cities have a broader impact on producer services;the port contributes to the development of wholesale and retail trades in the local city but the boost to consumer services comes mainly from spillover effects from other ports.This paper concludes that ports are still shaping economic geography by influencing the service sector,and inter-city coordination mechanisms are suggested because of the spillover effects.展开更多
基金supported by National Hi-tech Research and Development Program of China(863 Program, Grant No. 2007AA04Z132)National Natural Science Foundation of China(Grant No. 51175379)
文摘Typical multidisciplinary design optimization(MDO) has gradually been proposed to balance performances of lightweight, noise, vibration and harshness(NVH) and safety for instrument panel(IP) structure in the automotive development. Nevertheless, plastic constitutive relation of Polypropylene(PP) under different strain rates, has not been taken into consideration in current reliability-based and collaborative IP MDO design. In this paper, based on tensile test under different strain rates, the constitutive relation of Polypropylene material is studied. Impact simulation tests for head and knee bolster are carried out to meet the regulation of FMVSS 201 and FMVSS 208, respectively. NVH analysis is performed to obtain mainly the natural frequencies and corresponding mode shapes, while the crashworthiness analysis is employed to examine the crash behavior of IP structure. With the consideration of lightweight, NVH, head and knee bolster impact performance, design of experiment(DOE), response surface model(RSM), and collaborative optimization(CO) are applied to realize the determined and reliability-based optimizations, respectively. Furthermore, based on multi-objective genetic algorithm(MOGA), the optimal Pareto sets are completed to solve the multi-objective optimization(MOO) problem. The proposed research ensures the smoothness of Pareto set, enhances the ability of engineers to make a comprehensive decision about multi-objectives and choose the optimal design, and improves the quality and efficiency of MDO.
文摘The dashboard is the most important part of the large inner decoration of cars;it should not only have enough strength and rigidity,but also have a harmonious body model which can unify the theme.Besides,it needs to reach the goal of lightweight.In order to achieve these three goals,the car dashboard is made by engineering-plastics and adopts the technology of injection moulding.This paper introduces the keys of design and the advanced technology of large injection moulding for car dashboard.
基金Shanghai Philosophy and Social Science Fund(No.2018BJB008)Liberal Arts and Social Sciences Foundation of Ministry of Education in China(No.21YJC790060).
文摘Will ports become less important in a post-industrial period dominated by service industries?This paper examines the impact and the spillover effects of ports on city economies.The results show that ports contribute to city economies primarily through producer and consumer services.To be specific,ports can drive the development of port-related producer services,and port spillover effects from other cities have a broader impact on producer services;the port contributes to the development of wholesale and retail trades in the local city but the boost to consumer services comes mainly from spillover effects from other ports.This paper concludes that ports are still shaping economic geography by influencing the service sector,and inter-city coordination mechanisms are suggested because of the spillover effects.