载荷外推作为载荷谱编制的重要技术手段，当前研究缺乏对于载荷外推总体方法的全面梳理、马尔可夫稳态分布的求解方法适应性不够、缺乏不同非参频次外推方法的比较与选用原则，导致不便生成高精度载荷谱以支撑装备性能设计。围绕坦克在高机动和极限工况下的载荷谱编制问题，基于某坦克行进间身管位移数据样本，分别使用基于雨流矩阵及核密度估计的非参数外推法、基于马尔可夫链蒙特卡洛(Markov Chain Monte Carlo，MCMC)的信号重构法以及Metropolis-Hastings(简称MH)直接采样法进行了载荷频次外推，并针对MCMC的信号重构法提出了一种改良马尔可夫稳态分布的求解方法。应用所提出的频次-极值相结合的载荷外推总体方法对坦克身管位移进行了频次扩充与极值预测，并结合实车试验结果验证了方法的准确性。研究结果表明:改良的马尔可夫稳态分布求解方法是有效的;在样本长度足够、外推精度要求不甚高的情况下，MH直接采样法可作为一种新的频次外推方法;运用频次-极值相结合的载荷外推总体方法所得结果精度较高;形成的频次外推法选用原则对于载荷谱编制过程中的方法选择具有一定的指导意义。研究工作为装备载荷谱的高质量编制提供了成熟的技术路线和参考。
Overall Load Extrapolation Method Based on Frequency and Extreme Value Extrapolation
Load extrapolation,as an important technical means for compiling load spectra,is inconvenient to generate the high-precision load spectra to support equipment performance design due to lacking of the comprehensive review of overall load extrapolation method,the insufficient adaptability of solution method for Markov steady-state distribution,and the comparison and selection principles for different nonparametric frequency extrapolation methods.Focusing on the compilation of tank's load spectrum under high mobility and extreme conditions,the nonparametric extrapolation method based on rain flow matrix and kernel density estimation,the signal reconstruction based on Markov Chain Monte Carlo(MCMC)method,and the Metropolis-Hastings(MH)direct sampling method are used to perform the frequency extrapolation according to the barrel displacement dataset of a tank in motion.Besides,an improved Markov steady-state distribution solution method is proposed for the signal reconstruction method of MCMC.Finally,the proposed overall frequency-extreme load extrapolation method is used to expand the frequency and predict the extreme values of the dataset.The accuracy of overall method is verified based on experimental results.It is shown that the improved Markov steady-state distribution solution method is effective.The MH direct sampling method can be used as a new frequency extrapolation method when the sample length is sufficient and the extrapolation accuracy is not very high.The accuracy of overall frequency-extreme load extrapolation method is relatively high.The principles for selecting frequency extrapolation methods have certain guiding significance for the selection of methods in the process of compiling the load spectra.The research work provides a mature technical route and reference for the high-quality equipment load spectra compiling.
load extrapolationkernel density estimationMarkov Chain Monte Carlo methodMarkov steady-state distributionMetropolis-Hastings sampling
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