Brake systems are essential for the speed regulation or braking of a high-speed train.The vehicle dynamic performance under braking condition is complex and directly affects the reliability and running safety.To revea...Brake systems are essential for the speed regulation or braking of a high-speed train.The vehicle dynamic performance under braking condition is complex and directly affects the reliability and running safety.To reveal the vehicle dynamic behaviour in braking process,a comprehensive trailer car dynamics model(TCDM)considering brake systems is established in this paper.The dynamic interactions between the brake system and the other connected components are achieved using the brake disc-pad frictions,brake suspension systems,and wheel-rail interactions.The force and motion transmission from the brake system to the wheel-rail interface is performed by the proposed TCDM excited by track irregularity.In addition,the validity of TCDM is verified by experimental test results.On this basis,the dynamic behaviour of the coupled system is simulated and discussed.The findings indicate that the braking force significantly affects vehicle dynamic behaviour including the wheel-rail forces,suspension forces,wheelset torsional vibration,etc.The dynamic interactions within the brake system are also significantly affected by the vehicle vibration due to track irregularity.Besides,the developed TCDM can be further employed to the dynamic assessment of such a coupled mechanical system under different braking conditions.展开更多
The UNESCO label of World Heritage can attract a high number of tourists to heritage properties for their Outstanding Universal Values(OUV).Although international studies have demonstrated the World Heritage system ca...The UNESCO label of World Heritage can attract a high number of tourists to heritage properties for their Outstanding Universal Values(OUV).Although international studies have demonstrated the World Heritage system can contribute to stimulating cultural tourism and boosting the local economy,how this heritage-led development process promotes urban conservation and morphological changes in cities is yet to be explored adequately.This paper aims to explore the urban morphology of a historic Chinese city after its inscription on the UNESCO World Heritage List,taking the Old Town of Lijiang as case.The methods of spatial plan analysis and discourse analysis are used to analyse the data.The research findings have demonstrated that,theoretically,the Conzenian approach of urban morphology can be an effective framework for World Heritage OUV-monitoring.Methodologically,the analysis of spatial plans and multi-stakeholder interviews can reveal local urban morphology from macro to micro levels.Case-specifically in Lijiang,urban physical characteristics and building structures have been well maintained while traditional social fabric and neighbourhood networks have almost vanished.This research has incorporated the urban morphology approach into(world)heritage management in China,as well as worldwide,in order to maintain the balance between urban conservation and economic growth.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52205217 and U22A20181)the Natural Science Foundation of Sichuan(No.2022NSFSC1964).
文摘Brake systems are essential for the speed regulation or braking of a high-speed train.The vehicle dynamic performance under braking condition is complex and directly affects the reliability and running safety.To reveal the vehicle dynamic behaviour in braking process,a comprehensive trailer car dynamics model(TCDM)considering brake systems is established in this paper.The dynamic interactions between the brake system and the other connected components are achieved using the brake disc-pad frictions,brake suspension systems,and wheel-rail interactions.The force and motion transmission from the brake system to the wheel-rail interface is performed by the proposed TCDM excited by track irregularity.In addition,the validity of TCDM is verified by experimental test results.On this basis,the dynamic behaviour of the coupled system is simulated and discussed.The findings indicate that the braking force significantly affects vehicle dynamic behaviour including the wheel-rail forces,suspension forces,wheelset torsional vibration,etc.The dynamic interactions within the brake system are also significantly affected by the vehicle vibration due to track irregularity.Besides,the developed TCDM can be further employed to the dynamic assessment of such a coupled mechanical system under different braking conditions.
基金This work was supported by the Fundamental Research Funds for the Central Universities[2682022CX044]the China Postdoctoral Science Foundation[2021M702616].
文摘The UNESCO label of World Heritage can attract a high number of tourists to heritage properties for their Outstanding Universal Values(OUV).Although international studies have demonstrated the World Heritage system can contribute to stimulating cultural tourism and boosting the local economy,how this heritage-led development process promotes urban conservation and morphological changes in cities is yet to be explored adequately.This paper aims to explore the urban morphology of a historic Chinese city after its inscription on the UNESCO World Heritage List,taking the Old Town of Lijiang as case.The methods of spatial plan analysis and discourse analysis are used to analyse the data.The research findings have demonstrated that,theoretically,the Conzenian approach of urban morphology can be an effective framework for World Heritage OUV-monitoring.Methodologically,the analysis of spatial plans and multi-stakeholder interviews can reveal local urban morphology from macro to micro levels.Case-specifically in Lijiang,urban physical characteristics and building structures have been well maintained while traditional social fabric and neighbourhood networks have almost vanished.This research has incorporated the urban morphology approach into(world)heritage management in China,as well as worldwide,in order to maintain the balance between urban conservation and economic growth.
