Bus mass is an important factor that affects fuel consumption and one of the key input parameters associated with automatic shift and hybrid electric vehicle （HEV） energy management strategy. A city bus mass estimat...Bus mass is an important factor that affects fuel consumption and one of the key input parameters associated with automatic shift and hybrid electric vehicle （HEV） energy management strategy. A city bus mass estimation method based on kinetic energy theorem was proposed in this paper. The real-time data including vehicle speed and engine torque were collected by a remote data acquisition system. The samples in the process of being accelerated were selected to conduct vehicle mass estimation at the same bus stop with the same gear. The average estimation error is 2. 92% after the verification by actual data. Compared with the method based on recursive least squares, the algorithm based on kinetic energy theorem requires less sample length and the estimation error is smaller. Therefore, the method is more suitable for the bus mass estimation. The influences of gear, rolling resistance coefficient, wind resistance coefficient and road slope on mass estimation accuracy were analyzed.展开更多
The initiating condition for the accelerated creep of rocks has caused difficulty in analyzing the whole creep process.Moreover,the existing Nishihara model has evident shortcomings in describing the accelerated creep...The initiating condition for the accelerated creep of rocks has caused difficulty in analyzing the whole creep process.Moreover,the existing Nishihara model has evident shortcomings in describing the accelerated creep characteristics of the viscoplastic stage from the perspective of internal energy to analyze the mechanism of rock creep failure and determine the threshold of accelerated creep initiation.Based on the kinetic energy theorem,Perzyna viscoplastic theory,and the Nishihara model,a unified creep constitutive model that can describe the whole process of decaying creep,stable creep,and accelerated creep is established.Results reveal that the energy consumption and creep damage in the process of creep loading mainly come from the internal energy changes of geotechnical materials.The established creep model can not only describe the viscoelasticeplastic creep characteristics of rock,but also reflect the relationship between rock energy and creep deformation change.In addition,the research results provide a new method for determining the critical point of creep deformation and a new idea for studying the creep model and creep mechanical properties.展开更多
基金National International Cooperation in Science and Technology Special Project(No.2013DFG62890)
文摘Bus mass is an important factor that affects fuel consumption and one of the key input parameters associated with automatic shift and hybrid electric vehicle （HEV） energy management strategy. A city bus mass estimation method based on kinetic energy theorem was proposed in this paper. The real-time data including vehicle speed and engine torque were collected by a remote data acquisition system. The samples in the process of being accelerated were selected to conduct vehicle mass estimation at the same bus stop with the same gear. The average estimation error is 2. 92% after the verification by actual data. Compared with the method based on recursive least squares, the algorithm based on kinetic energy theorem requires less sample length and the estimation error is smaller. Therefore, the method is more suitable for the bus mass estimation. The influences of gear, rolling resistance coefficient, wind resistance coefficient and road slope on mass estimation accuracy were analyzed.
基金This work was supported by the National Natural Science Foundation of China(Grant No.41941018)the Science and Tech-nology Service Network Initiative of the Chinese Academy of Sci-ences(Grant No.KFJSTS-QYZD-174),and the Guangxi Natural Science Foundation(Grant No.2020GXNSFAA159125).
文摘The initiating condition for the accelerated creep of rocks has caused difficulty in analyzing the whole creep process.Moreover,the existing Nishihara model has evident shortcomings in describing the accelerated creep characteristics of the viscoplastic stage from the perspective of internal energy to analyze the mechanism of rock creep failure and determine the threshold of accelerated creep initiation.Based on the kinetic energy theorem,Perzyna viscoplastic theory,and the Nishihara model,a unified creep constitutive model that can describe the whole process of decaying creep,stable creep,and accelerated creep is established.Results reveal that the energy consumption and creep damage in the process of creep loading mainly come from the internal energy changes of geotechnical materials.The established creep model can not only describe the viscoelasticeplastic creep characteristics of rock,but also reflect the relationship between rock energy and creep deformation change.In addition,the research results provide a new method for determining the critical point of creep deformation and a new idea for studying the creep model and creep mechanical properties.
