﻿ 单点腐蚀船体板剩余疲劳寿命的数值计算
 舰船科学技术  2021, Vol. 43 Issue (7): 5-8    DOI: 10.3404/j.issn.1672-7649.2021.07.002 PDF

1. 中国人民解放军 91404部队，河北 秦皇岛 066001;
2. 海军装备部驻上海地区军事代表局驻上海地区第一军事代表室，上海 201913;
3. 同济大学 建筑工程系，上海 200092

Numerical calculation of the residual fatigue life of a hull plate with pit corrosion
WANG Hui-ting1, WANG Jin2, ZHANG Yue-lin3, HOU Zhi-nan1
1. No. 91404 Unit of PLA, Qinhuangdao 066001, China;
2. The First Military Representative Office of the Military Representative Bureau of the Ministry of Naval Equipment in Shanghai, Shanghai 201913, China;
3. Department of Building Engineering, Tongji University, Shanghai 200092, China
Abstract: Hull plates will be subjected to alternating tension/compression under wave load, so the influence of fatigue on the residual life of the hull plate, especially on the residual life of the hull plate with pitting corrosion, must be considered. In this paper, the residual fatigue life of single point corrosion hull plate is calculated. The results show that the error of stress concentration coefficient of hull plate with corrosion pit is less than 10% and the error of linear element is up to 40%. The diameter of corrosion pit has little effect on the fatigue life of single point corrosion hull plate, but the residual fatigue life of hull plate decreases rapidly with the increase of the depth of corrosion pit. It can be seen that for the stress concentration calculation of point corrosion steel plate, using quadratic element is more accurate than the linear element, and the effect of pit depth on the residual fatigue life of single point corrosion hull plate is more significant than that of pit diameter.
Key words: pit corrosion     hull plate     fatigue life
0 引　言

1 研究对象

 图 1 研究对象的几何模型 Fig. 1 Geometry of the subject
2 网格类型的选择

3 结果与讨论

d=10 mm，h=5 mm的情况为例，使用Abaqus进行应力计算，Fe-Safe进行疲劳寿命计算。蚀坑区域的网格进行了加密，网格总数为779，如图2所示。

 图 2 网格的划分 Fig. 2 Mesh of the subject

 图 3 应力云图 Fig. 3 Stress distribution

 图 4 剩余疲劳寿命（循环次数） Fig. 4 Residual fatigue life (Cyclic number)

 图 5 载荷缩放系数 Fig. 5 Load scale factor
3.1 蚀坑直径的影响

 图 6 船体板疲劳寿命随蚀坑直径的变化 Fig. 6 Fatigue life of the bull plate vs. diameter of the pit
3.2 蚀坑深度的影响

 图 7 船体板剩余寿命随蚀坑深度的变化 Fig. 7 Residual life of the hull plate vs. depth of the pit
3.3 含蚀坑船体板疲劳寿命的经验公式

 $N = 2\;084.3\exp \left(\frac{{0.397\;5}}{{h/t}}\right)\text{，}$ (1)
 $N = 1\;890.5{(h/t)^{ - 1.5929}}\text{。}$ (2)

4 结　语

1）对于点腐蚀钢板的应力集中计算，使用而此单元比使用线性单元更准确。

2）含圆柱形蚀坑船体板剩余疲劳寿命随蚀坑深度的增大而迅速减小；蚀坑直径对船体板疲劳寿命的影响不大。

3）使用幂函数对船体板疲劳寿命-蚀坑深度曲线进行拟合比使用倒指数函数更准确。

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