索道桥成桥状态确定与安全性分析验证

以积石峡1#索道桥为例,通过理论计算,确定索道桥空索与竣工两种状态下矢度的施工控制重点,并分析索道桥主要受力构件悬索与锚索的安全性,比对荷载试验结果等方面论述,表明索道桥结构的可靠性。同时也为同类索道桥施工提供了借鉴参考。     

新建包西铁路通道包头至大保当段Ⅳ级深埋砂岩段隧道支护参数研究

新包神铁路隧道Ⅳ级围岩基本为白垩系下统的泥质粉砂岩,在确保安全的前提下,为了达到较好的技术经济效果,设计前对围岩情况进行了深入细致的调查和研究,并进行准确完备的理论计算及经验类比验证,给出较为经济合理的支护参数,经施工实践检验,取得了良好的效果。     

地质雷达在莲花山隧道质量检测中的应用

结合地质雷达在广东江鹤高速公路莲花山隧道检测的工程实例,分析了隧道支护各种状况下的典型波形图像,简要介绍了地质雷达检测的应用效果。     

汽车安全气囊的使用及其注意事项

从安全气囊的工作原理着手,给出了安全气囊的控制原理,分析了其工作过程;指出了现有安全气囊在使用过程中的缺陷,提出了改进措施;最后总结了安全气囊在使用中应该注意的问题。     

高速公路沥青面层施工质量控制

沥青面层施工是高速公路工程施工中的一道关键工序,结合从事多条高速公路的施工实践,介绍了沥青面层施工过程各环节的质量控制方法,对现场施工具有一定的指导作用。     

Analysis of the car body stability performance after coupler jack-knifing during braking

This paper aims to improve car body stability performance by optimising locomotive parameters when coupler jack-knifing occurs during braking. In order to prevent car body instability behaviour caused by coupler jack-knifing, a multi-locomotive simulation model and a series of field braking tests are developed to analyse the influence of the secondary suspension and the secondary lateral stopper on the car body stability performance during braking. According to simulation and test results, increasing secondary lateral stiffness contributes to limit car body yaw angle during braking. However, it seriously affects the dynamic performance of the locomotive. For the secondary lateral stopper, its lateral stiffness and free clearance have a significant influence on improving the car body stability capacity, and have less effect on the dynamic performance of the locomotive. An optimised measure was proposed and adopted on the test locomotive. For the optimised locomotive, the lateral stiffness of secondary lateral stopper is increased to 7875?kN/m, while its free clearance is decreased to 10?mm. The optimised locomotive has excellent dynamic and safety performance. Comparing with the original locomotive, the maximum car body yaw angle and coupler rotation angle of the optimised locomotive were reduced by 59.25% and 53.19%, respectively, according to the practical application. The maximum derailment coefficient was 0.32, and the maximum wheelset lateral force was 39.5?kN. Hence, reasonable parameters of secondary lateral stopper can improve the car body stability capacity and the running safety of the heavy haul locomotive.     

A vehicle stability control strategy with adaptive neural network sliding mode theory based on system uncertainty approximation

Modelling uncertainty, parameter variation and unknown external disturbance are the major concerns in the development of an advanced controller for vehicle stability at the limits of handling. Sliding mode control (SMC) method has proved to be robust against parameter variation and unknown external disturbance with satisfactory tracking performance. But modelling uncertainty, such as errors caused in model simplification, is inevitable in model-based controller design, resulting in lowered control quality. The adaptive radial basis function network (ARBFN) can effectively improve the control performance against large system uncertainty by learning to approximate arbitrary nonlinear functions and ensure the global asymptotic stability of the closed-loop system. In this paper, a novel vehicle dynamics stability control strategy is proposed using the adaptive radial basis function network sliding mode control (ARBFN-SMC) to learn system uncertainty and eliminate its adverse effects. This strategy adopts a hierarchical control structure which consists of reference model layer, yaw moment control layer, braking torque allocation layer and executive layer. Co-simulation using MATLAB/Simulink and AMESim is conducted on a verified 15-DOF nonlinear vehicle system model with the integrated-electro-hydraulic brake system (I-EHB) actuator in a Sine With Dwell manoeuvre. The simulation results show that ARBFN-SMC scheme exhibits superior stability and tracking performance in different running conditions compared with SMC scheme.     

基于模糊物元分析法的军事运输方式选择

军事运输讲究快速性、高效性和经济性,如何合理地选择军事运输方式,是提高军事运输效率的关键。采用科学的方法对军事运输方式进行优化分析和选择,可以保证军事运输便捷高效。在分析影响军事运输方式选择的几种因素的基础上,引入模糊物元分析法,建立了军事运输方式选择模型,并通过实际应用,验证了该模型的可行性。应用模糊物元分析法能够定量评价各种军事运输方式的优劣,为运输管理决策提供理论依据。     

EPS中更精确的电机转速估计方法研究

电动助力转向系统中需要用到准确的助力电机转速信号,因此本文提出一种变内阻变反电动势系数的助力电机转速估计方法.通过测试直流电机内阻和反电动势系数随电机电流的变化曲线,从而得到电机转速更精确的估计表达式.通过对比试验验证可知,本文提出的电机转速估计方法能够显著提高估计精度.     

UGNX高级仿真在摩托车车轮设计中的应用

将摩托车车轮作为研究对象,运用UGNX高级仿真进行5种状态的受力分析,可为摩托车车轮的设计优化提供可靠依据。通过UGNX高级仿真的应用,从而提高摩托车车轮的综合性能水平,改进设计工艺,并直接应用于生产实际,从而大大提高产品的竞争力;无论是结构设计还是强度研究,运用UGNX高级仿真功能进行有限元分析都具有重要意义。