摘要
传统的船舶结构疲劳强度校核一般只考虑高周疲劳而忽略了低周疲劳。随着船舶结构向大型化发展以及最近海损事故的发生,低周疲劳问题引起了船舶行业的广泛关注。Urm等人于2004年对装卸载引起的油轮船体结构的低周疲劳问题进行了研究,并给出了计算方法,但具体的计算结果没有给出,许多问题没有解决,因此有必要对船舶结构低周疲劳的原因及校核方法进行深入的研究。针对这一问题,首先分析了引起船舶结构低周疲劳的原因;其次,对现有的S-N曲线外推得到低寿命区S-N曲线的可行性进行了分析,并将外推得到的低寿命区段曲线和经过试验验证的低周疲劳寿命曲线进行了比较;最后分析了波浪载荷等引起的小幅疲劳载荷以及满载和压载引起的大幅疲劳载荷导致的疲劳损伤的相互作用,从而提出了一种非线性累积计算模型。
In the traditional ship structure fatigue strength assessment only high cycle fatigue is taken into account, while the low cycle fatigue has usually been neglected. However, with the development of large-scaled ship structure and the damage of offshore structure, much attention has been focused on the low cycle fatigue. Urm et al. has investigated the low cycle fatigue of the tanker structure generated by the cargo loading and unloading and developed a simplified procedure. Since many problems have not been solved, it is necessary to further the study on the reason and assessment approach of the low cycle fatigue of the ship structure. In this paper, the reason and assessment approach have been presented and the quantitative results have been obtained. Based on the mechanism of the low cycle fatigue, the analysis of the low cycle life region extrapolated by the existing S-N curve is conducted and compared with the experiment. In addition, the fatigue damage interaction between the small amplitude fatigue load caused by the wave loads and large one owing to the full load and ballast has been analyzed, and a nonlinear cumulative damage model is developed.
出处
《中国造船》
EI
CSCD
北大核心
2007年第2期60-67,共8页
Shipbuilding of China
