FEM analyses for influences of stress corrosion and pressure solution on THM coupling in dual-porosity rock mass

With the models of stress corrosion and pressure solution, by Yasuhara et al., two computation conditions were designed for a hypothetical nuclear waste repository in an unsaturated dual-porosity rock mass: (i) the fracture apertures are changed with the stress corrosion and pressure solution (the porosity of rock matrix is also a function of stress); (ii) the fracture apertures and the porosity of rock matrix are constants. Then the corresponding two-dimensional FEM analyses for the coupled thermohydro-mec...     

Communication simulation of on-board diagnosis network in high-speed Maglev trains

The on-board diagnosis network is the nervous system of high-speed Maglev trains, connecting all controller, sensors, and corresponding devices to realize the information acquisition and control. In order to study the on-board diagnosis network’s security and reliability, a simulation model for the on-board diagnosis network of high-speed Maglev trains with the optimal network engineering tool (OPNET) was built to analyze the network’s performance, such as response error and bit error rate on the network load, throughput, and node-state response. The simulation model was verified with an actual on-board diagnosis network structure. The results show that the model results obtained are in good agreement with actual system performance and can be used to achieve actual communication network optimization and control algorithms.

     

Key techniques for predicting the uncertain trajectories of moving objects with dynamic environment awareness

Railway Engineering Science - Emerging technologies of wireless and mobile communication enable people to accumulate a large volume of time-stamped locations, which appear in the form of a...     

Performance study of combined test rig for metro train traction

This paper deals with a combined test rig for a traction system in the laboratory environment. An experimental system was designed and implemented to verify the performance of the traction system for a metro train. For a highly accurate control of the system, a hybrid control algorithm combining vector control and slip frequency control was applied to control the traction inverter. The design method of the flywheels, which represent the equivalent model of the train moment inertia, was elaborated. A train runtime diagnosis system was completed by adopting the multifunction vehicle bus (MVB) protocol. The dynamic performance of the metro power traction system was emulated under the control of the train runtime diagnosis system. Using the combined test rig, the performances of the traction system in traction, braking, temperature rise, etc., were verified through traction and breaking experiments.

     

An improved algorithm for fluid-structure interaction of high-speed trains under crosswind

Based on the train-track coupling dynamics and high-speed train aerodynamics, this paper deals with an improved algorithm for fluid-structure interaction of high-speed trains. In the algorithm, the data communication between fluid solver and structure solver is avoided by inserting the program of train-track coupling dynamics into fluid dynamics program, and the relaxation factor concerning the load boundary of the fluid-structure interface is introduced to improve the fluctuation and convergence of aerodynamic forces. With this method, the fluid-structure dynamics of a high-speed train are simulated under the condition that the velocity of crosswind is 13.8 m/s and the train speed is 350 km/h. When the relaxation factor equals 0.5, the fluctuation of aerodynamic forces is lower and its convergence is faster than in other cases. The side force and lateral displacement of the head train are compared between off-line simulation and co-simulation. Simulation results show that the fluid-structure interaction has a significant influence on the aerodynamics and attitude of the head train under crosswind conditions. In addition, the security indexes of the head train worsen after the fluid-structure interaction calculation. Therefore, the fluid-structure interaction calculation is necessary for high-speed trains.

     

汽车维修车间作业排序的优化模型及调度算法*

针对汽车维修车间调度缺乏科学规划,导致较长的客户等待时间和较低的设备利用率的问题,在结合优化调度理论的基础上, 对这一实际调度问题的特性、模型和算法进行了研究。首先从最小化目标、机器环境、加工特征和约束几方面分析了问题的特征,建立了对应的数学模型;然后根据问题特性设计了分解法与约束引导的启发式算法相结合的调度算法;最后以实例分析验证了算法的可行性。仿真结果表明了所用算法在优化目标函数值上的优越性。     

面向产业链协同商务平台的权限控制模型研究*

分析了产业链企业间协作关系和支持产业链企业间业务协同商务平台的特点,建立了面向动态联盟的四级授权控制模型,对联盟授权管理、企业按联盟协作类别的权限继承管理、企业部门授权管理和部门内具体操作人员的授权管理进行了研究,提出了产业链协同商务平台权限控制算法,并在汽车产业链协同商务平台权限管理中进行了应用验证。     

基于STM32的轨道方向不平顺检测系统设计

轨道不平顺是影响列车乘坐舒适性和平稳性的主要激励源,对轨道不平顺信号进行准确检测和有效的分析处理,以尽可能提高铁路维修效率,保障高速列车行车安全。为了准确检测轨道方向不平顺信号,基于惯性基准法原理,研制了以STM32F103 Cortex-M3 ARM处理器为控制核心的自动化检测系统。系统调理采集包括伺服加速度计、陀螺仪、倾角仪等多路传感器转换而来的模拟信号,然后传输到车载服务器中分析处理。检测结果以实时波形图的形式显示,能够准确有效地判断不平顺状态。     

决策表中基于对象的μ-约简方法研究

研究了不协调决策表中基于对象的μ-约简问题,给出了μ-约简的一些性质及等价定义,得到了μ-约简的判定定理和相应的可辨识矩阵及辨识公式,从而提供了不协调目标信息系统知识约简的新方法。并通过实例将决策表中基于对象的约简与整体约简进行了对比,结果表明前者可以得到更简洁的知识。该方法也适用于协调目标信息系统。     

基于微藻培养的沼液处理相关耦合技术进展

基于微藻培养的沼液处理相关耦合技术是近些年沼液资源化处理利用领域的研究热点。本文综述了沼液处理与CO₂固定耦合技术、沼液处理与高值生物质生产耦合技术、沼液处理与生态农业耦合技术等耦合技术的研究发展现状与优缺点，并指出了各耦合技术发展的关键问题，如沼液处理与CO₂固定耦合技术中高CO₂耐受性藻株选育与固碳影响机理研究问题、沼液处理与高值生物质生产耦合技术中低成本、低能耗高值生物质生产技术开发问题、沼液处理与生态农业耦合技术系统性评价体系缺乏问题等。最后，为促进耦合技术突破现有瓶颈，从微藻选育、微藻培养、沼液处理与沼气工程综合经济性4个角度提出相关的建议。