The new filling system is smooth filling without gas gap. It works well in avoiding the generation of defects such as porosity and inclusion. The pouring basin, sprue, runner and the gate of the bolster casting were d...The new filling system is smooth filling without gas gap. It works well in avoiding the generation of defects such as porosity and inclusion. The pouring basin, sprue, runner and the gate of the bolster casting were designed according to the principle of the new filling system. The filling and solidifciation process of the bolster casting were also simulated. It was found that the filling process was smooth, and air entrapment and shrinkage were avoided. Finally, a further validation of the new filling system of bolster casting was carried out in a foundry.展开更多
Sixteen operating conditions were determined by the standards JIS-7105 and JIS-7106. The strength under complex operating conditions was calculated with HyperWorks and the strength analysis confirmed eight dangerous p...Sixteen operating conditions were determined by the standards JIS-7105 and JIS-7106. The strength under complex operating conditions was calculated with HyperWorks and the strength analysis confirmed eight dangerous points of the metro bolster beam. Since the metro did not consider the impact of traffic lights and sudden road conditions, the load spectra at eight dangerous points were established by counting the running time,passenger flow,site layout,site quantity and turning situations. The fatigue life of the metro bolster beam was projected by the von Mises stress method and the critical plane method. The results of these two methods revealed that the maximum damage occurred at the dangerous point 7,and the fatigue life based on the critical plane method was shorter than that based on the von Mises stress method.Since the McDiarmid model considered the effect of the magnitude and direction of the normal stress and the amplitude of the shear stress,it is closer to the actual situations of the metro. Hence,the McDiarmid model based on the critical plane method is more reasonable,and the method of fatigue life prediction is also suitable to the metro bolster beam of other lines.展开更多
China Zambia diplomatic relations have a long history dating back to as early as 1964, and many cooperative milestones have been celebrated along the way. One that symbolizes the friendship and unity between the two n...China Zambia diplomatic relations have a long history dating back to as early as 1964, and many cooperative milestones have been celebrated along the way. One that symbolizes the friendship and unity between the two nations is the recent two-decade anniver sary of Bank of China （Zambia） Ltd. （BOC （Z） Ltd.）.展开更多
In the wake of the rapid economy and society development, phenomena such as industri-alisation, urbanisation, marketisation and the ageing of the population have shown an accelerating trend. As a result, mental health...In the wake of the rapid economy and society development, phenomena such as industri-alisation, urbanisation, marketisation and the ageing of the population have shown an accelerating trend. As a result, mental health issues due to these phenomena are increasingly serious, making mental health both concerning public health and societal issues that have a great impact on economic and social development.^1 In 2014, there were 16 million persons with severe mental disor-ders in China.展开更多
A simulation-driven design method which uses multiple optimization methods can effectively promote innovative structural design tion analysis can enormously improve the efficiency of modelling and solving.This study e...A simulation-driven design method which uses multiple optimization methods can effectively promote innovative structural design tion analysis can enormously improve the efficiency of modelling and solving.This study establishes a general workflow of structural and reduce the product development cycle.Meanwhile,the sub-model technology which has more detailed simulation and optimizaoptimization for a stainless-steel metro bolster by combining the simulation-driven design method and sub-model technology.In the sub-model definition phase,the end underframe sub-model which contains the bolster is obtained based on the whole car body finite element(FE)model,and the effectiveness of the end underframe sub-model is also proved.In the conceptual design phase,the is determined according to manufacturing processes and design experiences.In the detailed design phase,the thickness of each topology path inside the bolster is obtained by the topology method and the optimized structure of the inner ribs inside the bolster part of the bolster is determined by size optimization.The simulation analyses indicate that the requirements of static strength and can be decreased by 17.79% compared with the original bolster structure,which means that not only the lightweight design goal fatigue strength are fulfilled by the optimized bolster structure.Besides,the weight can be reduced by 11.18% and the weld length is achicved.but also the welding auantity and manufacturing difficulty are geatly reduced.The results show the effectiveness of the simulation-driven design method based on the sub-model technology in the structural optimization for key parts of rail transit vehicles.展开更多
Making every attempt to boost the sluggish U.S.economy, U.S.President Barack Obama has pledged incentive programs including tax cuts for the middle class that have "for generations,made our economy the envy of th...Making every attempt to boost the sluggish U.S.economy, U.S.President Barack Obama has pledged incentive programs including tax cuts for the middle class that have "for generations,made our economy the envy of the world." But the program may not be a panacea as income inequality in the United States becomes entrenched.Zhang Monan,a researcher with the State Information Center,discussed this issue in an article recently published in the China Securities Journal.Edited excerpts follow.展开更多
基金supported by the Natural Science Foundation of Liaoning Province (20092061)
文摘The new filling system is smooth filling without gas gap. It works well in avoiding the generation of defects such as porosity and inclusion. The pouring basin, sprue, runner and the gate of the bolster casting were designed according to the principle of the new filling system. The filling and solidifciation process of the bolster casting were also simulated. It was found that the filling process was smooth, and air entrapment and shrinkage were avoided. Finally, a further validation of the new filling system of bolster casting was carried out in a foundry.
基金National Key Technology Research and Development Program of China(No.2014BAF08B01)Collaborative Innovation Center of Major Machine Manufacturing in Liaoning,China
文摘Sixteen operating conditions were determined by the standards JIS-7105 and JIS-7106. The strength under complex operating conditions was calculated with HyperWorks and the strength analysis confirmed eight dangerous points of the metro bolster beam. Since the metro did not consider the impact of traffic lights and sudden road conditions, the load spectra at eight dangerous points were established by counting the running time,passenger flow,site layout,site quantity and turning situations. The fatigue life of the metro bolster beam was projected by the von Mises stress method and the critical plane method. The results of these two methods revealed that the maximum damage occurred at the dangerous point 7,and the fatigue life based on the critical plane method was shorter than that based on the von Mises stress method.Since the McDiarmid model considered the effect of the magnitude and direction of the normal stress and the amplitude of the shear stress,it is closer to the actual situations of the metro. Hence,the McDiarmid model based on the critical plane method is more reasonable,and the method of fatigue life prediction is also suitable to the metro bolster beam of other lines.
文摘China Zambia diplomatic relations have a long history dating back to as early as 1964, and many cooperative milestones have been celebrated along the way. One that symbolizes the friendship and unity between the two nations is the recent two-decade anniver sary of Bank of China （Zambia） Ltd. （BOC （Z） Ltd.）.
文摘In the wake of the rapid economy and society development, phenomena such as industri-alisation, urbanisation, marketisation and the ageing of the population have shown an accelerating trend. As a result, mental health issues due to these phenomena are increasingly serious, making mental health both concerning public health and societal issues that have a great impact on economic and social development.^1 In 2014, there were 16 million persons with severe mental disor-ders in China.
基金supported by the Science and Technology Research and Development Program of CRRC Cor por ation Limited(Gr ant No.2021CKB030)the Science and Technology Major Project of CRRC Corporation Limited(Grant No.2021CKZ008-3).
文摘A simulation-driven design method which uses multiple optimization methods can effectively promote innovative structural design tion analysis can enormously improve the efficiency of modelling and solving.This study establishes a general workflow of structural and reduce the product development cycle.Meanwhile,the sub-model technology which has more detailed simulation and optimizaoptimization for a stainless-steel metro bolster by combining the simulation-driven design method and sub-model technology.In the sub-model definition phase,the end underframe sub-model which contains the bolster is obtained based on the whole car body finite element(FE)model,and the effectiveness of the end underframe sub-model is also proved.In the conceptual design phase,the is determined according to manufacturing processes and design experiences.In the detailed design phase,the thickness of each topology path inside the bolster is obtained by the topology method and the optimized structure of the inner ribs inside the bolster part of the bolster is determined by size optimization.The simulation analyses indicate that the requirements of static strength and can be decreased by 17.79% compared with the original bolster structure,which means that not only the lightweight design goal fatigue strength are fulfilled by the optimized bolster structure.Besides,the weight can be reduced by 11.18% and the weld length is achicved.but also the welding auantity and manufacturing difficulty are geatly reduced.The results show the effectiveness of the simulation-driven design method based on the sub-model technology in the structural optimization for key parts of rail transit vehicles.
文摘Making every attempt to boost the sluggish U.S.economy, U.S.President Barack Obama has pledged incentive programs including tax cuts for the middle class that have "for generations,made our economy the envy of the world." But the program may not be a panacea as income inequality in the United States becomes entrenched.Zhang Monan,a researcher with the State Information Center,discussed this issue in an article recently published in the China Securities Journal.Edited excerpts follow.
