基于自适应核密度估计的接触网吊弦疲劳程序载荷谱编制方法OA

To effectively guide the design and fatigue tests of droppers for the 400 km/h high-speed railway catenary,a compilation method for the fatigue program load spectrum of droppers based on Adaptive Kernel Density Estimation(Adaptive KDE)was proposed.Firstly,a pantograph-catenary dynamic simulation model was established to reveal the vibration characteristics of droppers at a speed of 400 km/h,and the fatigue load cycles within the vibration period of droppers were extracted using the rainflow counting method.Next,an adaptive bandwidth factor was introduced,and a fatigue load probability density distribution model for droppers based on Adaptive KDE was proposed.The Monte Carlo simulation method was used to extrapolate and obtain the working fatigue loads of droppers under all working conditions.Finally,considering the actual vibration characteristics of droppers,a simplified fatigue program load spectrum for droppers and the corresponding test loading method were developed.The research results indicated that under the 400 km/h operating condition,the droppers were subjected to alternating fatigue load cycles within the vibration period,with the maximum tensile force reaching 497.71 N,and the stress concentration areas of the droppers were prone to fatigue failure.The fatigue load distribution of droppers was obtained using the Adaptive KDE method,which not only allowed extrapolation of dropper fatigue load frequency but also predicted fatigue loads of droppers at all levels under all working conditions.The extreme fatigue load amplitude of droppers increased from 248.9 N based on linear extrapolation to 264.9 N.The dropper fatigue program load spectrum compiled by the proposed method could reflect the fatigue damage caused to droppers by working loads under all operating conditions.The fatigue life of droppers was predicted to be approximately 1.172 million pantograph passes based on Miner's linear cumulative damage theory,providing a basis for determining dropper fatigue test parameters.