轨道车辆EVA电缆剩余寿命快速评估研究

Study on the Quick Evaluation of the Remaining Life of EVA Cables for Rail Vehicles

随着科技的发展,我国的交通运输水平已处于世界前列,特别是轨道车辆的发展,为我国人员流通、物资运输和经济的发展作出重大贡献。轨道交通列车运行过程中,车辆内部运行控制信号及电力的输送保障至关重要。在轨道交通列车上使用的薄壁控制电缆的外层护套绝缘材料种类中,有一种为乙烯-醋酸乙烯共聚物(EVA),该材料在酸性、潮湿等恶劣条件下易发生黄变、开裂、鼓包等现象,从而影响电缆的剩余寿命,使得电缆出现传输异常,影响列车正常运行,严重时可能出现短路发生火灾造成重大事故及人员伤亡。为对轨道车辆用乙烯-醋酸乙烯共聚物(EVA)电缆的剩余寿命进行快速评估,文章采用热重分析法(TGA)研究了不同老化程度的EVA绝缘材料的热分解特性,计算出了其对应的热分解活化能。在此基础上,参照ASTM E 1877-00:2021标准中的方法建立了EVA绝缘材料的热寿命方程。研究结果表明:热分解特性能够用来评估轨道车辆用EVA电缆的实际老化情况,结合建立的热寿命方程能完成电缆使用状况的快速评估,与传统评估方法相比,该方法操作更加简单。

With the development of science and technology,China’s transportation level has been in the forefront of the world,especially the development of rail vehicles,which has made a significant contribution to China’s personnel circulation,material transportation and economic development.In the process of rail transit train operation,the control signal and power transmission guarantee of vehicle internal operation are very important.Among the outer sheath insulation materials of thin-wall control cables used on rail transit trains,one is ethylene-vinyl acetate(EVA).This material is prone to yellowing,cracking,and bulging under harsh conditions such as acidity and humidity,thus affecting the remaining life of the cable,causing abnormal transmission of the cable and affecting the normal operation of the train.In severe cases,short-circuit fires may occur and cause major accidents and casualties.To quickly evaluate the remaining life of ethylene-vinyl acetate(EVA)cables for rail vehicles,this article uses the method of thermogravimetric analysis(TGA)to study the thermal decomposition characteristics of the EVA insulating material of different ageing degrees and work out the corresponding thermal decomposition activation energy.On this basis,the article makes reference to the method described in ASTM E 1877-00:2021 to establish the thermal life equation for the EVA insulating material.According to the study result,the thermal decomposition characteristics can be used to evaluate the actual ageing condition of EVA cables for rail vehicles,and combining the established thermal life equation,it’s possible to quickly evaluate the use condition of the cables.Compared with the conventional evaluating method,this method is easier to operate.