基于ISSA-VMD的地铁构架应力谱门槛值自适应确定方法  

Adaptive Method for Determining the Threshold Value of Metro Frame Stress Spectrum Based on ISSA-VMD

作　　者：薛海[1] 叶层林 和永峰 陈江涛 XUE Hai;YE Cenglin;HE Yongfeng;CHEN Jiangtao(School of Mechatronic Engineering,Lanzhou Jiaotong University,Lanzhou Gansu 730070,China)

机构地区：[1]兰州交通大学机电工程学院,甘肃兰州730070

出　　处：《中国铁道科学》2024年第4期180-188,共9页China Railway Science

基　　金：甘肃省教育厅高校教师创新基金资助项目(2023A-043);甘肃省自然科学基金资助项目(23JRRA909);兰州交通大学青年科学基金资助项目(2022048)。

摘　　要：针对地铁构架应力谱编制过程中小应力循环舍弃缺乏标准可依的问题,提出基于改进麻雀搜索算法(ISSA)和应力-时间历程信号变分模态分解(VMD)的应力谱门槛值自适应确定方法。首先,通过融合Tent混沌映射、鱼鹰优化算法和柯西变异策略改进麻雀搜索算法,从而避免陷入局部最优,提高分析效率;其次,采用ISSA优化VMD的分解个数和惩罚因子,实现关键参数确定;最后,根据最优参数组合,对应力信号进行VMD分解,并结合疲劳损伤占比、均方根和均方误差等参数对分解得到不同分量信号的中心频率进行综合分析,提取损伤占比较大的信号频率作为截止频率,从频域层面实现小应力门槛值的确定。结果表明:采用此方法确定的小应力门槛值使得应力雨流循环总数降低17.1%,实际损伤较传统方法所得结果减少7.8%,在有效反映应力所造成疲劳效应的同时保留了应力循环特性,提高了应力谱编制效率,从而为地铁构架应力谱编制过程中小应力门槛值的合理确定提供了参考。To address the absence of standardized criteria for discarding small stress thresholds in the compilation of metro framework stress spectrum,an adaptive threshold determination method applied to stress-time history signal optimized for Variational Mode Decomposition(VMD)is proposed based on Improved Sparrow Search Algorithm(ISSA).Firstly,the Sparrow Search Algorithm is improved by integrating Tent chaotic mapping,Osprey Optimization Algorithm,and Cauchy mutation strategy to avoid local optima and enhance analysis efficiency.Secondly,ISSA is employed to optimize the decomposition number and penalty factor for determining key parameters.Finally,based on the optimal parameter combination,the stress signal undergoes VMD decomposition,followed by a comprehensive analysis of central frequencies of different component signals,incorporating metrics such as fatigue damage proportion,Root Mean Square,and Root Mean Square Error.The signal frequency accounting for a significant proportion of damage is identified as the cutoff frequency,facilitating the determination of the small stress threshold from a frequency domain perspective.The results demonstrate that the proposed method reduces the total number of stress rain-flow cycles by 17.1%and the actual damage by 7.8%compared to traditional approaches.This not only effectively captures the fatigue effects induced by stress but also preserves the characteristics of stress cycles,thereby enhancing the efficiency of stress spectrum compilation.This study provides a reference for the rational determination of small stress thresholds during the compilation of metro framework stress spectrum.

关 键 词：地铁构架 应力谱 小应力门槛值 疲劳损伤 ISSA-VMD 

分 类 号：U231[交通运输工程—道路与铁道工程]