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基于随机缺陷理论和概率论方法,计算杆件的腐蚀截面积在服役时间内连续14年的均值和方差,将腐蚀截面积均值反推得到随时间变化的杆件均匀腐蚀深度,从而确定杆件连续14年的腐蚀模型。结合局部环向腐蚀钢管试验建立合理的有限元模型,对腐蚀钢管进行系统的研究,得出了考虑环向不同腐蚀深度和腐蚀面积时钢管极限承载力的近似公式。然后使用ANSYS软件对某网架工程实例进行考虑局部随机腐蚀的模拟研究。将局部腐蚀分为支座处单边、双边、三边、周边4种情况,对整体结构进行静、动力非线性分析。结果表明,在所选腐蚀参数下,该网架局部环向腐蚀引起的整体破坏发生在腐蚀第13年,结构破坏前没有明显预兆,且破坏过程的结构反应时间很短,危害性很大。
Based on the theory of stochastic defects and probability theory, the mean and variance of the corroded cross-sectional area of the bars during 14-year service life are calculated, and the mean corroded cross-sectional area is inversely estimated to obtain the uniform corrosion depth of the bars over time. Corrosion model for 14 consecutive years. In this paper, a reasonable finite element model is established based on the experiment of local circumferential corrosion of steel pipe. The corrosion of steel pipe is systematically studied. The approximate formula of the ultimate bearing capacity of steel pipe is obtained when considering the corrosion depth and area. And then use ANSYS software to simulate a certain rack engineering case considering the local random corrosion. The local corrosion is divided into four locations of unilateral, bilateral, three sides and periphery of support, and the static and dynamic nonlinear analysis of the whole structure is carried out. The results show that under the selected corrosion parameters, the overall damage caused by the local ring corrosion of the grid occurs in the 13th year of erosive and there is no obvious sign before the structural failure, and the structural reaction time of the destruction process is very short and has great danger.