Fatigue Strength Analysis of Ship’s Welded Structures Based on Method of Notch Stress

doi:10.16183/j.cnki.jsjtu.2023.307

Abstract

Abstract:

To address the fatigue strength problem of ship structures, the notch stress method is applied to typical structural joints focusing on weld toe and weld root. First, the basic principles of notch stress method and the notch fatigue analysis process of ship structure are introduced. Then, six typical joint types are set up for the double bottom structure of a product oil tanker. The local notch stress analysis of the fatigue hot spot is conducted using the finite element sub-modeling technology, allowing the determination of the notch stress concentration factor at the weld toe and weld root. Finally, based on the harmonised common structural rules (HCSR), the fatigue load and load condition of the ship structure are calculated, and the fatigue analysis of six typical joint types is performed. The results show that under the same load conditions, the notch stress concentration factor at the weld toe of each hot spot is smaller than that at the weld root, and the joint type 3 has the lowest fatigue damage value among the joint types, which suggests this type can improve the fatigue resistance of the hull.

Key words: ship structure, fatigue strength, notch stress, sub-model method, harmonised common structural rules (HCSR)

CLC Number:

U661.43

ZHEN Chunbo, LIU Shihao, ZHANG Aifeng, XING Shizhu, ZHANG Runze. Fatigue Strength Analysis of Ship’s Welded Structures Based on Method of Notch Stress[J]. Journal of Shanghai Jiao Tong University, 2025, 59(4): 458-465.

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References 16

[1]	张爱青, 薛鸿祥, 唐文勇. 晃荡载荷作用下液化天然气船泵塔结构疲劳寿命分析方法[J]. 上海交通大学学报, 2012, 46(3): 363-367.
	ZHANG Aiqing, XUE Hongxiang, TANG Wen-yong. Fatigue life analysis method of pump tower structure of liquefied natural gas ship under sloshing load[J]. Journal of Shanghai Jiao Tong University, 2012, 46(3): 363-367.
[2]	余宏淦, 黄小平, 张永矿. 基于谱分析和裂纹扩展方法的舱口角隅疲劳寿命预报方法[J]. 上海交通大学学报, 2019, 53(2): 153-160. doi: 10.16183/j.cnki.jsjtu.2019.02.005
	YU Honggan, HUANG Xiaoping, ZHANG Yong-kuang. Fatigue life prediction method of hatch corner based on spectral analysis and crack propagation method[J]. Journal of Shanghai Jiao Tong University, 2019, 53(2): 153-160.
[3]	HOBBACHER A F. Recommendations for fatigue design of welded joints and components[M]. Cham, Switzerland: Springer, 2016.
[4]	FRICKE W. Round-robin study on stress analysis for the effective notch stress approach[J]. Welding in the World, 2007, 51(3): 68-79.
[5]	FISCHER C, FRICKE W, RIZZO C M. Fatigue assessment of web-stiffened corners in plated structures by local approaches[J]. Ship Technology Research, 2018, 65(2): 69-78.
[6]	NGUYEN K T, GARBATOV Y, SOARES C G. Fatigue damage assessment of a tanker structural detail based on the effective notch stress approach[C]// Maritime Technology and Engineering. London, UK: Taylor & Francis Group, 2012: 363-373.
[7]	FRICKE W, VAN A, PAETZOLD H. Fatigue strength investigations of welded details of stiffened plate structures in steel ships[J]. International Journal of Fatigue, 2012, 34(1): 17-26.
[8]	FRICKE W, PAETZOLD H. Full-scale fatigue tests of ship structures to validate the S-N approaches for fatigue strength assessment[J]. Marine Structures, 2010, 23(1): 115-130.
[9]	严仁军, 何丰, 谌伟. 基于缺口应力法的焊接接头疲劳强度评估[J]. 武汉理工大学学报(交通科学与工程版), 2017, 41(5): 766-769.
	YAN Renjun, HE Feng, CHEN Wei. Fatigue strength evaluation of welded joints based on notch stress method[J]. Journal of Wuhan University of Technology (Transportation Science and Engineering), 2017, 41(5): 766-769.
[10]	刘旭, 张开林, 姚远, 等. 基于缺口应力法的焊接接头疲劳分析[J]. 工程力学, 2016(6): 209-214.
	LIU Xu, ZHANG Kailin, YAO Yuan, et al. Fatigue analysis of welded joints based on notch stress method[J]. Engineering Mechanics, 2016(6): 209-214.
[11]	胡鑫, 李艳青, 黄进浩. HFMI处理的钢制焊接接头疲劳评估模型探讨[J]. 焊接学报, 2022, 43(3): 80-86. doi: 10.12073/j.hjxb.20210703003
	HU Xin, LI Yanqing, HUANG Jinhao. Discussion on fatigue assessment model of HFMI treated steel welded joints[J]. Welding Institution, 2022, 43(3): 80-86.
[12]	周张义, 王雨舟, 杨欣. 基于不同应力法的焊接构架纵向角接头疲劳累积损伤评估[J]. 焊接学报, 2018, 39(8): 18-22. doi: 10.12073/j.hjxb.2018390193
	ZHOU Zhangyi, WANG Yuzhou, YANG Xin. Fatigue cumulative damage assessment of longitudinal fillet joints of welded frame based on different stress methods[J]. Welding Institution, 2018, 39(8): 18-22.
[13]	姜朝勇, 赵鑫源, 魏苇, 等. 基于有效缺口应力的地铁构架疲劳损伤研究[J]. 机车电传动, 2022(2): 135-140.
	JIANG Chaoyong, ZHAO Xinyuan, WEI Wei, et al. Research on fatigue damage of subway frame based on effective notch stress[J]. Locomotive Electric Transmission, 2022(2): 135-140.
[14]	NEUBER H. Theorie der technischen Formzahl[J]. Forschung Im Ingenieurwesen, 1936(7): 271-274.
[15]	RADAJ D, LAZZARIN P, BERTO F. Generalized Neuber concept of fictitious notch rounding[J]. International Journal of Fatigue, 2013, 51(6): 105-115.
[16]	IACS. Harmonised commom structural rules: HCSR[S]. Beijing, China: International Association of Classification Societies, 2015.

位置	(D_x, D_y, D_z)/m		(R_x, R_y, R_z)/(°)
位置	海水动压力	船体梁载荷	海水动压力	船体梁载荷
左侧截断面	(0, 0, 0)	(0, 0, 0)	(-, 0, 0)	(0, 0, 0)
右侧截断面	(0, 0, 0)	(0, 0, 0)	(-, 0, 0)	(0, 0, 0)
后端截断面	(0, -, -)	(0, -, -)	(-, 0, 0)	(-, 0, 0)
前端截断面	(0, -, -)	(0.001, -, -)	(-, 0, 0)	(-, 0, 0)