螺栓结合面微观接触特性的不确定性量化

Uncertainty Quantification of Micro-contact Characteristics of Bolt Joint Surface

针对螺栓结合面微观接触特性具有不确定性,传统基于确定性理论建立的模型难以完整表征结合面微观接触特性的问题,提出了一种基于蒙特卡洛法的螺栓结合面微观接触特性的不确定性量化方法。首先,基于分形理论,表征了同一粗糙度结合面微凸体轮廓高度,并采用矩谱法求解了结合面表面形貌参数区间;其次,利用中心极限定理,将表面形貌参数区间变为符合微凸体轮廓高度分布的高斯分布函数,解决了随机抽样误差的累加造成的置信水平降低;最后,将表面形貌参数的不确定性嵌入蒙特卡洛法,获得了结合面接触特性的区间估计,通过对比分析揭示了考虑不确定性因素时接触间隙对接触特性的影响规律。研究表明,表面形貌参数的不确定性对螺栓结合面接触特性变化具有显著影响,并导致不确定性的影响不断累加。该方法为准确量化螺栓结合面的不确定性提供了理论依据与参考。

There are obvious uncertainties in the micro-contact characteristics of the bolt joint surface.Traditional models based on the deterministic theory are difficult to completely characterize the micro-contact characteristics of the joint surface.For this reason,a Monte Carlo method based on the uncertainty quantification method of the micro contact characteristics of the bolt joint surface is proposed.First,based on the fractal theory,the profile height of the asperity of the bonding surface with the same roughness is characterized,and the surface topography parameter range of the bonding surface is solved by the moment spectrum method.Then,using the central limit theorem,the surface topography parameter interval is changed to a Gaussian distribution function conforming to the profile height distribution of the asperity,which solves the reduction in confidence level caused by the accumulation of random sampling errors.Finally,the uncertainty of the surface topography parameters is embedded in the Monte-Carlo method,and the interval estimation of the contact characteristics of the bonding surface is obtained.Through comparative analysis,the influence of the contact gap on the contact characteristics is revealed when considering the uncertain factors.Studies have shown that the uncertainty of surface topography parameters has a significant impact on the change of the contact characteristics of the bolt joint surface,and causes the influence of uncertainty to accumulate.This method provides a theoretical basis and reference for accurately quantifying the uncertainty of the bolt joint surface.