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Articles

by Kangning Yang
79 Views, 0 PDF Downloads

Analyzed the fatigue crack characteristics near the safety lifting seat hole of the speed-up passenger car bogie,proposed the hypothesis that structural vibration fatigue caused by resonance phenomenon is the most important cause of crack in this part. through finite element simulation, the front 1-10 order mode shape,analyzed the measured acceleration and dynamic stress tests of each order mode frequency on the line.Obtains Equivalent Stress,Acceleration and Its Main Frequency ,and carries out comparative analysis with finite element simulation results. Based on mastering the failure mechanism of safety hanger.Optimize the structure of safety hanger and its fixing mode through structural improvement and adjustment of connection mode, and carry out line test on new structure,and evaluate its safety and economy.The research results show that:is affected by normal bus line conditions,safety boom vibration frequency(acceleration main frequency is 91.78Hz Main frequency of dynamic stress 91.00Hz and 4 Mode Frequency of Order(95.Calculated by Finite Element Method 79Hz.)The power spectral density of longitudinal acceleration of the safety boom which is close to each other and generates resonance is much larger than its transverse value and vertical value,which is consistent with the running direction of the train.Therefore,Vibration fatigue causes cracks to be generated at the edge of the safety suspension seat hole and 5mmthick gasket,is added on both sides of the bolt hole, and the safety boom is changed from a steel plate bending structure to a steel wire rope flexible structure.The equivalent stress amplitude at the bolt hole can be reduced to the greatest extent,and the fatigue damage accumulation is reduced. The improved safety boom meets 120010,000 kilometer usage requirement,and achieves better economic effect.

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Articles

by Deyu Li
68 Views, 0 PDF Downloads

Aiming at the problem of tram cross-line bridge construction,comprehensively compares and selects 4 cross-line bridge schemes,selects a design scheme suitable for engineering practice.from the perspectives of economy,urban planning,structural safety,,implementation difficulty, landscape requirements,traffic impact, etc. The analysis results show that,when trams need to pass through existing overpass bridges ,small bridges are preferred to be demolished for new construction or width reconstruction,medium and large bridges are recommended to consider bypass scheme.

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Articles

by Jun Zhao
85 Views, 0 PDF Downloads

Cities are densely populated, economically developed, and highly concentrated in social wealth. They are also areas with high social vulnerability to natural disasters. The unpredictability and randomness of unexpected events put forward higher requirements for urban emergency transportation under natural disasters. In order to reduce the losses caused to the city by natural disasters, implement traffic management in an orderly way and improve the efficiency of emergency evacuation, the traffic behavior and the application of traffic simulation technology in emergency evacuation of emergencies at home and abroad are compared and analyzed. Focus on natural disasters and post-disaster related research in economically developed areas of China, and explore the reference of advanced research methods abroad in China's actual environment.

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Articles

by Xiangchen Wang
74 Views, 0 PDF Downloads

Essentials Freight Carrying Capacity of Middle Reaches of Yangtze River is Data Base of Shipping Development Planning.Connecting segments of different sizes in the middle reaches of the Yangtze river to form a multi-stage waterway,taking the cargo flow between any port of departure and the port of destination as a variable,the maximum sum of cargo flow as an objective function ,taking the cargo network, OD matrix and the capacity of each segment as limiting conditions ,using the maximum value of the objective function to characterize the cargo carrying capacity of the middle reaches of the Yangtze river waterway .Applying Complex Network Theory and Method,Combining Port Throughput Data, Calculating Freight Network, OD and Matrix;Applying Ship Following Theory ,Combining Ship Domain Parameters, Calculating Passage Capacity of Each Segment.The research results show that,has a freight carrying capacity of 68 in the middle reaches of the Yangtze River8 billion and T,Among them, the freight carrying capacity of the downstream channel in the middle reaches of the Yangtze River 36.9 billion and T,Restricted leg to Yue yang-Wuhan leg, Freight,Restricted leg to Huangshi-Jiujiang leg.

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Articles

by Shengrong Wu
64 Views, 0 PDF Downloads

Based on the overlapping tunnel between Huancheng south road station and Kunming railway station in the first phase of Kunming metro project, the influence of excavation face support pressure and grouting pressure on the tunnel is studied.By means of finite element numerical simulation, the effects of soil chamber pressure and grouting pressure on the surface subsidence and the structural stress of the lining of the tube piece in the lower hole are analyzed.The study shows that the influence of grouting pressure is more significant, the shield driving should ensure that the excavation face support pressure is not less than the original horizontal stress of the stratum, and the grouting pressure should be controlled within the range of 0.8- 1.0 times the original stress of the stratum.

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