The wheel-rail force measurement is of great importance to the condition monitoring and safety evaluation of railway vehicles. In this paper, an improved indirect method for wheel-rail force measurement is proposed to...The wheel-rail force measurement is of great importance to the condition monitoring and safety evaluation of railway vehicles. In this paper, an improved indirect method for wheel-rail force measurement is proposed to evaluate the running safety of railway vehicles. In this method, the equilibrium equations of a suspended wheelset are derived and the wheel-rail forces are then be obtained from measured suspension and inertia forces. This indirect method avoids structural modifications to the wheelset and is applicable to the long-term operation of railway vehicles. As the wheel-rail lateral forces at two sides of the wheelset are difficult to separate, a new derailment criterion by combined use of wheelset derailment coefficient and wheel unloading ratio is proposed. To illustrate its effectiveness, the indirect method is applied to safety evaluation of rail- way vehicles in different scenarios, such as the cross wind safety of a high-speed train and the safety of a metro vehicle with hunting motions. Then, the feasibility of using this method to identify wheel-rail forces for low-floor light rail vehicles with resilient wheels is discussed. The values identified by this method is compared with that by Simpack simulation for the same low-floor vehicle, which shows a good coincidence between them in the time domain of the wheelset lateral force and the wheel-rail vertical force. In addition, use of the method to determine the high-frequency wheel-rail interaction forces reveals that it is possible to identify the high-frequency wheel-rail forces through the accelerations on the axle box.展开更多
工业控制系统(Industrial Control Systems,ICSs)是关系国计民生的关键基础设施系统。针对工业控制系统的网络攻击可造成严重的经济损失和社会负面效应。随着工业互联网的发展,越来越多的工业控制系统接入互联网,在提高生产效率的同时,...工业控制系统(Industrial Control Systems,ICSs)是关系国计民生的关键基础设施系统。针对工业控制系统的网络攻击可造成严重的经济损失和社会负面效应。随着工业互联网的发展,越来越多的工业控制系统接入互联网,在提高生产效率的同时,也使得工业控制系统面临着更加严峻的网络攻击威胁态势。由此,企业会部署各类安全措施,以期有效保护系统。然而,由于“攻防不对等”,防御者普遍缺乏对于攻击的有效了解,所部署安全措施的防护效果无法做出有效的评估,从而难以做出改进。ICS ATT&CK(Adversarial Tactics,Techniques and Common Knowledge)框架的提出,为工控领域提供了统一的攻击战术、技术知识库。该框架可有效指导工业控制系统的安全防护建设。本文针对工业控制系统所面临的检测能力评估、防护策略制定、威胁狩猎等难题,结合美国国家标准和技术协会(NIST)提出的IPDRR(Identify-Protect-Detection-Respond-Recover)能力模型、钻石模型(Diamond Model)等,探索利用ICS ATT&CK框架制定更加稳健的工业控制系统安全防护策略,为企业的网络安全防护体系建设提供借鉴和指导。展开更多
针对高速列车的动力学性能评价标准中所涉及的评价内容、评价方法、评价指标及限值展开综述,围绕蛇行运动稳定性、脱轨安全性和运行平稳性展开标准分析和对比,包括ISO系列、UIC系列、EN系列、TSI系列、FRA系列、APTA系列和中国国标等法...针对高速列车的动力学性能评价标准中所涉及的评价内容、评价方法、评价指标及限值展开综述,围绕蛇行运动稳定性、脱轨安全性和运行平稳性展开标准分析和对比,包括ISO系列、UIC系列、EN系列、TSI系列、FRA系列、APTA系列和中国国标等法律规范、行业标准、技术规范等,指出不足或改进建议;对具有代表性的动力学标准进行详细对比,包括新旧版本国标《机车车辆动力学性能评定及试验鉴定规范》(GB/T 5599)、国际铁路联盟Testing and Approval of RailwayVehicles from the Point of View of Their Dynamic Behaviour—Safety—Track Fatigue—Running Behaviour(UIC 518)、俄罗斯Railway Multiple Units—Durability and Dynamics Requirements(GOST/R 55495)等;对北美FRA和APTA系列标准规定的理想轨道激励下动态响应、准静态性能评价方法等进行应用示范。研究结果表明:蛇行运动稳定性均通过构架横向加速度、构架力或轮轨力进行评判,而数值仿真、台架和线路试验需选择对应适用的方法;结合现阶段中国高速列车的长期服役动力学性能,若列车以400 km·h^(-1)及以上速度运行时,建议加速度滤波带宽仍采用0.5~10.0 Hz,幅值限值建议7 Hz以内为8 m·s^(-2),而7~9 Hz放宽至10 m·s^(-2),并持续10次、2 s或100 m;针对爬轨脱轨安全性评估,现有标准均基于轮轨力和车轮抬升量进行动态和静态评判,但在指标限值、持续作用时间或运行距离上存在差异,建议采用车轮脱轨系数和轮重减载率的联合评判方法;新版GB/T 5599删除了倾覆系数和轮轨横向力指标,放宽了轮重减载率限值,轮轴横向力限值维持不变;GOST/R 55495评价方法不区分车辆类型,采用构架力而非轮轨力对运行安全性进行评价,横垂向平稳性指标计算时采用相同的频域加权,且低频段加权带宽及幅值显著比GB/T 5599大,不对平稳性指标进行分级评价;复兴号CR400BF动车组的运行安全性指标和平稳性指标同时满足GB/T 5599和GOST/R 55495标准要求;采用北美标准对某160 km·h^(^(-1))客车进行理想轨道激励下动态响应分析,8类不平顺激扰中的重复高低和单次高低不平顺工况较为恶劣,6个评价指标中的轮重减载率和车体垂向加速度容易超限。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. U1334206 and No. 51475388)Science & Technology Development Project of China Railway Corporation (Grant No. J012-C)
文摘The wheel-rail force measurement is of great importance to the condition monitoring and safety evaluation of railway vehicles. In this paper, an improved indirect method for wheel-rail force measurement is proposed to evaluate the running safety of railway vehicles. In this method, the equilibrium equations of a suspended wheelset are derived and the wheel-rail forces are then be obtained from measured suspension and inertia forces. This indirect method avoids structural modifications to the wheelset and is applicable to the long-term operation of railway vehicles. As the wheel-rail lateral forces at two sides of the wheelset are difficult to separate, a new derailment criterion by combined use of wheelset derailment coefficient and wheel unloading ratio is proposed. To illustrate its effectiveness, the indirect method is applied to safety evaluation of rail- way vehicles in different scenarios, such as the cross wind safety of a high-speed train and the safety of a metro vehicle with hunting motions. Then, the feasibility of using this method to identify wheel-rail forces for low-floor light rail vehicles with resilient wheels is discussed. The values identified by this method is compared with that by Simpack simulation for the same low-floor vehicle, which shows a good coincidence between them in the time domain of the wheelset lateral force and the wheel-rail vertical force. In addition, use of the method to determine the high-frequency wheel-rail interaction forces reveals that it is possible to identify the high-frequency wheel-rail forces through the accelerations on the axle box.
文摘工业控制系统(Industrial Control Systems,ICSs)是关系国计民生的关键基础设施系统。针对工业控制系统的网络攻击可造成严重的经济损失和社会负面效应。随着工业互联网的发展,越来越多的工业控制系统接入互联网,在提高生产效率的同时,也使得工业控制系统面临着更加严峻的网络攻击威胁态势。由此,企业会部署各类安全措施,以期有效保护系统。然而,由于“攻防不对等”,防御者普遍缺乏对于攻击的有效了解,所部署安全措施的防护效果无法做出有效的评估,从而难以做出改进。ICS ATT&CK(Adversarial Tactics,Techniques and Common Knowledge)框架的提出,为工控领域提供了统一的攻击战术、技术知识库。该框架可有效指导工业控制系统的安全防护建设。本文针对工业控制系统所面临的检测能力评估、防护策略制定、威胁狩猎等难题,结合美国国家标准和技术协会(NIST)提出的IPDRR(Identify-Protect-Detection-Respond-Recover)能力模型、钻石模型(Diamond Model)等,探索利用ICS ATT&CK框架制定更加稳健的工业控制系统安全防护策略,为企业的网络安全防护体系建设提供借鉴和指导。
文摘针对高速列车的动力学性能评价标准中所涉及的评价内容、评价方法、评价指标及限值展开综述,围绕蛇行运动稳定性、脱轨安全性和运行平稳性展开标准分析和对比,包括ISO系列、UIC系列、EN系列、TSI系列、FRA系列、APTA系列和中国国标等法律规范、行业标准、技术规范等,指出不足或改进建议;对具有代表性的动力学标准进行详细对比,包括新旧版本国标《机车车辆动力学性能评定及试验鉴定规范》(GB/T 5599)、国际铁路联盟Testing and Approval of RailwayVehicles from the Point of View of Their Dynamic Behaviour—Safety—Track Fatigue—Running Behaviour(UIC 518)、俄罗斯Railway Multiple Units—Durability and Dynamics Requirements(GOST/R 55495)等;对北美FRA和APTA系列标准规定的理想轨道激励下动态响应、准静态性能评价方法等进行应用示范。研究结果表明:蛇行运动稳定性均通过构架横向加速度、构架力或轮轨力进行评判,而数值仿真、台架和线路试验需选择对应适用的方法;结合现阶段中国高速列车的长期服役动力学性能,若列车以400 km·h^(-1)及以上速度运行时,建议加速度滤波带宽仍采用0.5~10.0 Hz,幅值限值建议7 Hz以内为8 m·s^(-2),而7~9 Hz放宽至10 m·s^(-2),并持续10次、2 s或100 m;针对爬轨脱轨安全性评估,现有标准均基于轮轨力和车轮抬升量进行动态和静态评判,但在指标限值、持续作用时间或运行距离上存在差异,建议采用车轮脱轨系数和轮重减载率的联合评判方法;新版GB/T 5599删除了倾覆系数和轮轨横向力指标,放宽了轮重减载率限值,轮轴横向力限值维持不变;GOST/R 55495评价方法不区分车辆类型,采用构架力而非轮轨力对运行安全性进行评价,横垂向平稳性指标计算时采用相同的频域加权,且低频段加权带宽及幅值显著比GB/T 5599大,不对平稳性指标进行分级评价;复兴号CR400BF动车组的运行安全性指标和平稳性指标同时满足GB/T 5599和GOST/R 55495标准要求;采用北美标准对某160 km·h^(^(-1))客车进行理想轨道激励下动态响应分析,8类不平顺激扰中的重复高低和单次高低不平顺工况较为恶劣,6个评价指标中的轮重减载率和车体垂向加速度容易超限。
