By comprehensive analysis and design optimization of barrier structure parameters, a new type of beam-and-post steel barrier was invented according to impact test condition and acceptance criteria of cross-sea bridge barrier. Full-scale impact tests and finite elements analysis were conducted to do safty evalution of the barrier. The results show that, ASI value is 1.62 for test and that is 1.67 for FEA, THIV is 30.7km/h for test and that is 31.2km/h for FEA. Working width is 0.88m for test and that is 0.62m for FEA. Occupant risk evaluation index can meet the requirements of level B and the working width can meet the requirements of level W3. Both of tracking and posture of vehicles are well. The study results above show that safety performance of cross-sea bridge barrier can meet or exceed the acceptance criteria. FEA results are consistent with Full-scale impact test, which validate the reliability of FEA. cross-sea bridge barrier can meet the highest test level for beam-and-post steel barrier, which can defend the out-of-control vehicles effectively and help to ensure the bridge safety.
Building energy consumption is huge, with the emergence of global energy crisis and environmental problems and the concept of low carbon environmental protection, in order to relieve the strained situation of world energy, energy-saving building began to get attention widely. By means of the reasonable design and material selection for architecture, energy-saving buildings reduce the operation energy consumption, through scientific methods and using environmental protection materials to raise science and technology content of construction, by internal control of building, such as temperature, lighting, noise within the range of suitable for human settlement, to provide a healthy, comfortable and ecological living space for residents.
Abstract:In order to improve the aerodynamic performance of high-speed trains running in open air, a multi-objective optimization design method of the streamlined head shape of high-speed trains is proposed. The total aerodynamic drag force of the high-speed train and the maximum surface sound power of the head coach are set as the optimization objectives and the automatic multi-objective optimization design of the streamlined head shape is carried out. The parametric model of a new type super high-speed train with three carriages is established and five design variables of the head shape are extracted. The regions of the flow fields around trains are automatically meshed by the script file of ICEM CFD software, and the aerodynamic forces and the surface sound power of noise source of high-speed trains are automatically calculated by the script file of FLUENT software. The design variables are automatically updated by non-dominated sorting genetic algorithm-II (NSGA-II) to achieve the automatic optimization design of the head shape of the super high-speed train. After optimization, the correlations between the optimization design variables and the optimization objectives are analyzed, and the key design variables which influence the optimization objectives are obtained. The results show that the correlations between the optimization design variables and the two optimization objectives are the same, and only the values of correlation coefficients are different. A set of Pareto-optimal head shapes are obtained through the multi-objective optimization design. Compared with the original train, the total aerodynamic drag force of the optimized train is reduced up to 2.91%, and the maximum surface sound power of the head coach is reduced up to 7.47%.Key words:multi-objective optimization;high-speed train;genetic algorithm;aerodynamic drag;surface sound power 0 前言 *
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