Low-frequency carbody swaying phenomenon often occurs to railway vehicles due to hunting instability,which seriously deteriorates the ride comfort of passengers.This paper investigates low-frequency carbody swaying th...Low-frequency carbody swaying phenomenon often occurs to railway vehicles due to hunting instability,which seriously deteriorates the ride comfort of passengers.This paper investigates low-frequency carbody swaying through experimental analysis and numerical simulation.In the tests,the carbody acceleration,the wheel-rail profiles,and the dynamic characteristics of dampers were measured to understand the characteristics of the abnormal carbody vibration and to find out its primary contributor.Linear and nonlinear numerical simulations on the mechanism and optimization measures were carried out to solve this carbody swaying issue.The results showed that the carbody swaying is the manifest of carbody hunting instability.The low equivalent conicity and the decrease of dynamic damping of the yaw damper are probably the cause of this phenomenon.The optimization measures to increase the equivalent conicity and dynamic damping of the yaw damper were put forward and verified by on-track tests.The results of this study could enrich the knowledge of carbody hunting and provide a reference for solving abnormal carbody vibrations.展开更多
The complexity of the actual operating environment of EMU trains and the interaction between the reliability of system components have become a huge challenge for the maintenance scheduling of EMU trains. In response ...The complexity of the actual operating environment of EMU trains and the interaction between the reliability of system components have become a huge challenge for the maintenance scheduling of EMU trains. In response to these problems, the evolution of reliability and failure rate under the influence of environmental factors, failure correlations and economy correlations is analyzed. We assume bogie systems form the EMU train in series. The failure correlation matrix of the bogie systems is modeled. With the lowest total maintenance cost as the optimization objective, a decision-making model for EMU train maintenance is established. A dynamic maintenance strategy is proposed for the model, which can improve maintenance plans efficiently. Artificial bee colony algorithm is applied to further iteratively optimize the threshold parameters in the strategy. The results are calculated and verified by a numerical example. The results show the effectiveness of the maintenance decision model. The dynamic maintenance strategy in this paper is compared with the traditional opportunistic maintenance strategy. The proposed maintenance strategy outperforms the traditional opportunistic maintenance strategy in the numerical example.展开更多
针对200km/h EMU铸钢轴箱体存在的缩松、裂纹铸造缺陷问题,采用铸造模拟软件MAG-MASOFT对铸件的充型、凝固过程进行了温度场、流场的模拟计算,获得了优化的轴箱体铸造工艺方案,消除了200 km/h EMU轴箱体惯性缩松及裂纹问题。优化的铸造...针对200km/h EMU铸钢轴箱体存在的缩松、裂纹铸造缺陷问题,采用铸造模拟软件MAG-MASOFT对铸件的充型、凝固过程进行了温度场、流场的模拟计算,获得了优化的轴箱体铸造工艺方案,消除了200 km/h EMU轴箱体惯性缩松及裂纹问题。优化的铸造工艺,其工艺稳定性好,批量生产铸件成品率达到了95%以上,大大降低了铸件的制造成本。展开更多
基金supported by the National Key R&D Program of China under grant number 2018YFB1201701.
文摘Low-frequency carbody swaying phenomenon often occurs to railway vehicles due to hunting instability,which seriously deteriorates the ride comfort of passengers.This paper investigates low-frequency carbody swaying through experimental analysis and numerical simulation.In the tests,the carbody acceleration,the wheel-rail profiles,and the dynamic characteristics of dampers were measured to understand the characteristics of the abnormal carbody vibration and to find out its primary contributor.Linear and nonlinear numerical simulations on the mechanism and optimization measures were carried out to solve this carbody swaying issue.The results showed that the carbody swaying is the manifest of carbody hunting instability.The low equivalent conicity and the decrease of dynamic damping of the yaw damper are probably the cause of this phenomenon.The optimization measures to increase the equivalent conicity and dynamic damping of the yaw damper were put forward and verified by on-track tests.The results of this study could enrich the knowledge of carbody hunting and provide a reference for solving abnormal carbody vibrations.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 72061022)。
文摘The complexity of the actual operating environment of EMU trains and the interaction between the reliability of system components have become a huge challenge for the maintenance scheduling of EMU trains. In response to these problems, the evolution of reliability and failure rate under the influence of environmental factors, failure correlations and economy correlations is analyzed. We assume bogie systems form the EMU train in series. The failure correlation matrix of the bogie systems is modeled. With the lowest total maintenance cost as the optimization objective, a decision-making model for EMU train maintenance is established. A dynamic maintenance strategy is proposed for the model, which can improve maintenance plans efficiently. Artificial bee colony algorithm is applied to further iteratively optimize the threshold parameters in the strategy. The results are calculated and verified by a numerical example. The results show the effectiveness of the maintenance decision model. The dynamic maintenance strategy in this paper is compared with the traditional opportunistic maintenance strategy. The proposed maintenance strategy outperforms the traditional opportunistic maintenance strategy in the numerical example.
文摘针对200km/h EMU铸钢轴箱体存在的缩松、裂纹铸造缺陷问题,采用铸造模拟软件MAG-MASOFT对铸件的充型、凝固过程进行了温度场、流场的模拟计算,获得了优化的轴箱体铸造工艺方案,消除了200 km/h EMU轴箱体惯性缩松及裂纹问题。优化的铸造工艺,其工艺稳定性好,批量生产铸件成品率达到了95%以上,大大降低了铸件的制造成本。
