压路机液压系统污染问题探讨

压路机污染物主要来源于污染物入侵系统和维护保养不当.评定污染度有三种方法.我国等效采用IS04406污染物等级标准.在控制污染方面,主机生产厂家和用户均应采取相应措施.     

高水压、大流量高原隧道富水区治理技术

详细介绍了关角隧道4号斜井高水压、大水量区域的治理方案，内容包括新型堵水材料选择、注浆堵水技术、投入机械设备，以及针对相应情况采取的技术措施。施工实践表明，该施工方案合理可行，效果良好。     

沥青洒布车液压系统参数设计

在确定沥青洒布车液压系统驱动方案的基础上,进行了沥青洒布车液压传动系统原理设计,并分别对沥青泵驱动系统和导热油泵驱动系统进行了设计.计算结果证明,所设计的液压系统能满足沥青洒布车的要求,能使得系统工作在高效区.     

梯形渠道工程及水力最佳断面的研究

笔者从各方面分析论证了梯形渠道水力最优断面宽深比为b/h =2 (1+m2 -m) ,对进一步认识梯形渠道水力最优及其应用具有一定意义 .     

自卸汽车液压系统故障2例

针对实际工作中出现的2例自卸汽车液压系统的故障,介绍了一种可以根据经验和借助适当的检测工具,对相关零部件进行从简单到复杂的逐一排查方法,以及使故障得以快速排除的分析思路。     

基于液压技术的地铁防淹门系统方案

地铁防淹门系统是一种防灾设备。国内使用的防淹门有升降式和平开式两种。通过对两种地铁防淹门系统的功能和现状的分析,提出了采用液压启闭机形式的升降式防淹门系统的新设计思路。介绍了该方案的系统构成和性能特点,并通过对启闭机液压原理、控制特性以及液压技术发展情况的描述论证了方案具备可实施性。     

On the scattering of test data and the significance of the standard coefficients ‘dynamic stiffness’ and ‘loss angle’ for hydraulic engine mounts

Based on the test results, a study on the scattering of the standard coefficients c _dyn and δ within the test cycles on a standard testing machine as well as within the samples of a batch of hydraulic engine mounts is performed; furthermore, an estimate for the systematic error caused by the testing machine is given. By a simulated example, the pronounced sensitivity of the response of the engine to the scattering of c _dyn and δ as well as to even small deviations of the hysteresis curves for otherwise identical values of the standard coefficients is demonstrated. As a main result, it is found that the most important source of uncertainty is scattering within the batch, which, in conjunction with the observed sensitivity of the response of the engine, raises the question for the meaningful level of sophistication of a model for predictive purposes.     

Identification of nonlinear systems using modified particle swarm optimisation: a hydraulic suspension system

This paper presents a novel modified particle swarm optimisation (MPSO) algorithm to identify nonlinear systems. The case of study is a hydraulic suspension system with a complicated nonlinear model. One of the main goals of system identification is to design a model-based controller such as a nonlinear controller using the feedback linearisation. Once the model is identified, the found parameters may be used to design or tune the controller. We introduce a novel mutation mechanism to enhance the global search ability and increase the convergence speed. The MPSO is used to find the optimum values of parameters by minimising the fitness function. The performance of MPSO is compared with genetic algorithm and alternative particle swarm optimisation algorithms in parameter identification. The presented comparisons confirm the superiority of MPSO algorithm in terms of the convergence speed and the accuracy without the premature convergence problem. Furthermore, MPSO is improved to detect any changes of system parameters, which can be used for designing an adaptive controller. Simulation results show the success of the proposed algorithm in tracking time-varying parameters.     

基于复杂网络的列车辅助驾驶危险致因传播模型

为了解预期功能安全(SOTIF)相关危险致因在基于智能感知的列车辅助驾驶系统 (IATDAS)中的传播特性，提升针对该类系统的危险控制能力，本文提出基于复杂网络的IATDAS 系统危险致因传播模型。该模型在SOTIF危险致因网络的基础上，提供了全局容量-负载传播机制，能有效刻画IATDAS系统的危险致因传播机制。案例分析结果表明：本文所提模型能够解决复杂致因关系下既有模型与系统实际情况不符的问题，如对于具有较长后续传播路径的致因，本文模型能够刻画其较难导致危险的实际特征；依据本文模型实施传播控制，可以显著降低危险致因的传播速度，如对影响节点范围大、前期影响节点数量增加快的危险因素进行控制时，可使其平均传播速度降低68%，比随机控制策略多降58%。该模型可以为IATDAS系统的SOTIF相关危险控制提供决策基础。     

基于细-宏观数据交互的桥梁水毁数值仿真

为精细化探究桥梁水毁倒塌机理，基于计算流体力学与泥沙动力学数值仿真，得到桥梁冲刷形态演变与波流力时程数据，构建桥梁水毁全过程的连续倒塌数值模型；通过开发细-宏观数据交互接口，将冲刷所致边界条件改变与波流力对桥梁结构作用效应实时传递至结构域桥梁连续倒塌数值模型，高精度连续仿真冲刷发展与波流力作用下桥梁水毁全程力学响应与结构形态演化；最后，通过河源东江大桥倒塌案例分析，验证该仿真方法与数据交互接口的正确性和有效性。结果表明：河源东江大桥连续倒塌可能由冲刷掏空基础后倾斜、拱脚薄弱节点失效以及非制动墩承受不平衡水平推力所致；所提出的仿真方法可实现冲刷仿真、波流力计算与结构倒塌分析的同步交互实施，可为从水文源头探究桥梁水毁失效机理与倒塌模式提供精准高效的分析工具，为桥梁抗水设计、评估以及未来规范修订提供理论基础与技术手段。