摘要
给出简化载荷谱法和雨流计数统计载荷谱法2种估算柔性接触网疲劳寿命的方法,并比较二者所得疲劳寿命的差别。简化载荷谱法将接触线单元的应力时程简化为一个最大的应力循环,经Goodman直线修正后由S-N曲线直接得到接触线各单元的疲劳寿命;雨流计数统计载荷谱法对接触线单元的应力时程进行雨流计数,得到各单元的各级应力循环;经Goodman直线修正之后,使用S-N曲线得到各单元在各级应力幅下破坏的循环次数,然后基于Miner线性累积损伤理论得到接触线各单元的疲劳寿命。简化载荷谱法忽略最大应力循环之外的其他应力循环,所得疲劳寿命偏高。针对一组参数用2种算法得到接触线的最终寿命差别很小。可以近似使用简化载荷谱法分析接触线的疲劳寿命,2种算法寿命差别较大的接触线单元用雨流计数法分析疲劳寿命更为精确。
This paper gives two methods to estimate fatigue life of the flexible overhead catenary system: simplified load spectrum method and rain-flow counting method,and compares their differences of fatigue life.In the simplified load spectrum method,stress-time curve of contact wire unit is simplified as a maximum stress cycle;after the correction of Goodman straight-line,the fatigue life of each unit on contact wire is gained directly through the S-N curves.In the rain-flow counting method,the rain-flow counting is utilized for stress-time curve of each contact wire unit,and each stress cycle of each unit at all levels is obtained;after the correction of Goodman straight-line,the cycle number of the unit when fractured in different stress amplitudes is gained through the S-N curves;then based on Miner linear cumulative damage theory,the fatigue life of contact wire unit is estimated.In theory,the simplified load spectrum method ignores other stress cycles except the maximum stress cycle,so the fatigue life gained is higher.Aiming at a set of parameters,this paper calculates final fatigue life of contact wire through two methods respectively,and the difference is very small.In conclusion,the simplified load spectrum method can be used approximatively,but in those positions where the difference of two methods is greater,the rain-flow counting method should be adopted to analyze the fatigue life of the catenary more accurately.
出处
《铁道标准设计》
北大核心
2012年第4期116-119,共4页
Railway Standard Design
基金
国家科技支撑计划(2009G09-1-7)
关键词
柔性接触网
疲劳寿命
简化载荷谱
雨流计数法
flexible overhead catenary
fatigue life
simplified load spectrum method
rain-flow counting method
