大型油轮船体结构的疲劳寿命评估

疲劳破坏是工程结构或构件失效的主要原因之一，疲劳破坏也是船舶结构失效的一种主要形式。近几年，国内外开始重视船舶结构的疲劳问题，并展开了这方面的理论和设计规范的研究工作。由于船体节点的多样性和荷载的复杂性，使得船体结构的疲劳计算也相当复杂。为此，工程中采用了大量的简化方法和经验公式。文中阐述了船体结构疲劳强度校核的基本原理和基于S-N曲线的线性累积损伤方法。针对油轮的特点，确定了疲劳校核方法，参照DNV规范编制了船体结构疲劳强度校核程序，并利用该方法完成了大型油轮（VLCC）典型节点处的疲劳寿命评估。

Fatigue Strength Assessment of Oil Tank Structures

The fatigue is the main failure mode in ship structures. Fatigue strength assessment procedures have been implemented in the ship design rules by many classification societies. Generally, the simplified methods are employed in the engineering because the variable structure details and the different load conditions make the problem very complicated. The general principles of the fatigue life assessment of ship structures are reviewed and a practical method to assess the oil tank structures is proposed. A program for calculating fatigue loads, stresses and cumulative damages as well as fatigue life are compiled. As an example, the fatigue life of an oil tank structures are analyzed, and the program are proved to be effective and reasonable.