液化天然气B型独立液货舱结构低周疲劳研究

基于某B型独立液货舱为研究对象,开展液化天然气(LNG)船码头装卸货工况下的结构应力和温度场热应力分析,重点针对液货舱水平强框处连接节点计算其因装卸货受力和温度变化所引起的疲劳累积损伤。研究结果表明,部分研究疲劳节点由装卸货产生的低周疲劳损伤在整个结构疲劳累积损伤中的占比较大,对结构疲劳损伤起主导作用,需要在液货舱疲劳强度分析中予以重点关注。因此,对此类B型独立液货舱进行结构设计必须考虑低周疲劳的影响。

Studies on the low-cycle fatigue for Type B Independent tank structure of LNG Carrier

In the process of unloading and unloading for LNG carrier, the alternately low-cycle change of the cargo pressure and temperature load in the cargo tank caused by changes in load conditions, has some influence on the fatigue strength of the liquid cargo tank structure, although the number of cycles is limited in the entire life cycle .This paper is based on the structure and thermal stress analysis of the LNG ship for the type B independent cargo tank in loading and unloading cases, and to calculate the fatigue cumulative damage in the transition area between horizontal strong frame of the cargo tank structure by change of the cargo pressure and temperature load. The results show that the low-cycle fatigue damage by changes in load conditions has relatively higher proportion in the entire structural fatigue assessment and the significant influence on fatigue life, and is proposed to focus on in the structural design and fatigue strength analysis of cargo tanks.