基于三维Copula函数的蚀坑预测模型

通过盐雾腐蚀试验研究了钢绞线在不同应力幅作用下的腐蚀规律,并且观测了钢绞线的腐蚀形态.从概率角度出发,得到了钢绞线蚀坑长度、宽度和深度的独立分布形式,然后基于三维Copula函数得到三者之间的联合分布规律,提出了三维蚀坑预测模型,并通过显著性检验对该模型进行了验证.结果 表明:Clayton Copula函数对于模拟蚀坑三维联合分布具有较高的精度;蚀坑使得钢绞线的抗拉强度和延伸率急剧下降,是钢绞线疲劳寿命下降的主要原因;三维蚀坑预测模型的提出,可以为预测钢绞线的腐蚀疲劳寿命提供参考.

Pit Prediction Model based on Three-Dimensional Copula Function

pit is an important factor to affect the fatigue life of steel strand. this paper simulate the corrosion laws of steel strands in chloride salt environment under different stress amplitudes, by the salt spray corrosion tests and the independent distribution forms of long axis, minor axis and depth of erosion pit are obtained, from the perspective of probability. Besides, the joint distribution model include the three parameters is set up, based on the three-dimensional copula function and the correctness of the model is verified by significance test.The results show that Clayton copula function has high accuracy in simulating the distribution of pits.In addition, It is find that the tensile strength and elongation of steel strands decreased mainly caused by corrosion and then the fatigue life of steel strand will be reduced. The three-dimensional corrosion pit prediction model is conducive to further study of the corrosion fatigue life of steel strands.