Finite Element Method pre and post processing tool FAST and a self-programmed software optim3.f are used for structural optimization analysis for main parts of a railway locomotive support vehicle. For best structure optimization, a program code which has considered 3D structure optimization was added to original program to automatically erase nodes whose effective stress was smaller than a given value. Detailed analysis are undertaken to main causes of stress concentration, and using optimized design methods, effective measure for reforming stress concentration and a new structure were proposed.

In this paper, based on traffic flow characteristics of urban highways and discreteness 才 theory of numerical analysis, a series of traffic models including traffic generation model, car-following model, and lane changing models were built to study microscopic traffic flow simulation and calculation methods of urban road signal controlled intersections. Then a numerical simulation C++ program was coded on Linux platform using discrete mesh method after determining a reasonable traffic flow simulation parameters, and simulation results were verified using traffic survey data analysis. Finally, the basis for how to optimize urban road intersections congestion state and how to make decisions about traffic management and control of signalized intersections were provided, and the optimized way to solve traffic delay was hereby recommended.

In this paper, based on survey data of delays on intersections in urban highways and in accordance with theoretical capacity of each traffic lane, various reasons of delay in intersections are analyzed numerically. A discrete traffic model to simulate traffic in intersections using Gaussian mesh method is built. After modifying intersection properties, weight of each factor in terms of their effect to capacity is acquired. An optimized way to solve traffic delay is hereby recommended.

In this research, 2D and 3D FEM model of one stringer of a semi-trailer was built. Mesh generation and boundary conditions definition was processed on FAST software. Effective stress distribution diagram was obtained after FEM analysis to stringe structure under various working conditions. Main stress concentration area was defined and causes for stress concentration was analyzed. After all, suggestion for improvement and structure optimization was given.

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