Detroit has been one of the leading cities in the 20th century in the US. Manufacturing, especially, automobile industry created and continued the thriving economy in Detroit, MI in the early to mid-1900s. When outso...Detroit has been one of the leading cities in the 20th century in the US. Manufacturing, especially, automobile industry created and continued the thriving economy in Detroit, MI in the early to mid-1900s. When outsourcing impacted the industry, people began to leave the city. That turned into a demographic catastrophe in Detroit. Economy had continuously fallen and many of the properties were foreclosed. After the housing market crash in 2008, a big economic crisis effected all country. After such a strong economic crisis, Detroit has been desperately in need of economic revival which has begun to turn around very slowly in last 10 years. In this paper, Detroit has been investigated through the experienced constructional problems. Sustainable solutions for Detroit are discussed in a broader aspect. The main purpose of the research is to understand the current problems in construction in Detroit after a decade of the economic crisis and bring sustainable solutions for urban redevelopment and rehabilitation for Detroit. Paper also details the problems in Detroit area, reasons behind the complications, components/parameters, constraints/limitations, solutions, people involved and expected results.展开更多
With the development of vehicle gearbox to high-power-density and high-speed, how to predict and optimize the dynamic characteristics of vehicle gearbox becomes increasingly prominent. Aiming at the vehicle gearbox, t...With the development of vehicle gearbox to high-power-density and high-speed, how to predict and optimize the dynamic characteristics of vehicle gearbox becomes increasingly prominent. Aiming at the vehicle gearbox, this paper comprehensively and deeply studies the dynamic characteristics under the multi-boundary conditions. The generation mechanism of the multi-source excitations triggering the gearbox vibration is analyzed firstly. The vibration transfer path of the gearbox is explored. Secondly, the engine excitation, the gear meshing excitation and the bearing support load are numerically calculated. According to the finite element method,a fluid-solid coupling finite element model of the gearbox body is established to predict the gearbox dynamic responses based on the Galerkin method and the Hamiltonian variational principle. Finally, the effects of the excitation condition, oil height and reinforcement forms on the vibration responses of the gearbox body are thoroughly studied by simulation. The analysis indicates that it not only helps to modify and improve the method of forecasting the gearbox dynamic response, and also provides the theoretical and technical guidance for the gearbox design and optimization.展开更多
文摘Detroit has been one of the leading cities in the 20th century in the US. Manufacturing, especially, automobile industry created and continued the thriving economy in Detroit, MI in the early to mid-1900s. When outsourcing impacted the industry, people began to leave the city. That turned into a demographic catastrophe in Detroit. Economy had continuously fallen and many of the properties were foreclosed. After the housing market crash in 2008, a big economic crisis effected all country. After such a strong economic crisis, Detroit has been desperately in need of economic revival which has begun to turn around very slowly in last 10 years. In this paper, Detroit has been investigated through the experienced constructional problems. Sustainable solutions for Detroit are discussed in a broader aspect. The main purpose of the research is to understand the current problems in construction in Detroit after a decade of the economic crisis and bring sustainable solutions for urban redevelopment and rehabilitation for Detroit. Paper also details the problems in Detroit area, reasons behind the complications, components/parameters, constraints/limitations, solutions, people involved and expected results.
基金the National Natural Science Foundation of China(Nos.51505402 and 51405410)the Education and Scientific Research Projects of Young and Middle-Aged Teachers in Fujian Province in 2014(No.JA14245)
文摘With the development of vehicle gearbox to high-power-density and high-speed, how to predict and optimize the dynamic characteristics of vehicle gearbox becomes increasingly prominent. Aiming at the vehicle gearbox, this paper comprehensively and deeply studies the dynamic characteristics under the multi-boundary conditions. The generation mechanism of the multi-source excitations triggering the gearbox vibration is analyzed firstly. The vibration transfer path of the gearbox is explored. Secondly, the engine excitation, the gear meshing excitation and the bearing support load are numerically calculated. According to the finite element method,a fluid-solid coupling finite element model of the gearbox body is established to predict the gearbox dynamic responses based on the Galerkin method and the Hamiltonian variational principle. Finally, the effects of the excitation condition, oil height and reinforcement forms on the vibration responses of the gearbox body are thoroughly studied by simulation. The analysis indicates that it not only helps to modify and improve the method of forecasting the gearbox dynamic response, and also provides the theoretical and technical guidance for the gearbox design and optimization.
