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
Key words
Metro framework/Stress spectrum/Small stress threshold value/Fatigue damage/ISSA-VMD
维普
万方数据