环境烈度因子在FPSO船体梁强度评估中的应用

The application of environmental severity factor on hull girder strength evaluation of FPSO

由于作业方式不同,用于计算FPSO与不限定航线条件下船舶设计载荷的规范计算公式不一样,如何将现有的关于普通海船的规范用于FPSO的设计评估是FPSO研究中的关键问题。基于现有常规钢质海船规范,文章采用环境烈度因子(ESF)对用于计算运营于无限航区船舶设计载荷的规范公式进行修正,将修正后的公式作为FPSO设计载荷的计算公式。利用所得FPSO载荷计算公式计算某30万吨FPSO设计载荷,并采用薄壁梁理论对船体梁强度进行校核。将校核结果与未经ESF修正的船体梁校核结果进行比较,发现未经ESF修正的船体梁校核结果明显偏大。同时,采用薄壁梁理论进行船体梁剪切强度评估,可以避免建立全船有限元模型。

The rule formulas which used to calculate the design loads of FPSO and navigating-flee ships are different because of the different operating conditions between FPSO and common ships. It is a key point that how to apply current seagoing ships rules to designing and evaluating FPSO. Based on the current seagoing ships rules, the thesis adopted environ- ment severe factors to modify the formulas which intended to calculate design loads of ships operating in unrestricted ser- vice conditions. The modified formulas were used to calculate the design loads for FPSO. Then the obtained formulas were utilized to calculate the design loads ofa FPSO with 300 000 DWT which followed by a hull girder strength check based on thin-wall theory. The check results of ESF method were compared with those which weren＇t modified with ESF and the lat- ter was greater than the former obviously. Meanwhile, it was a time-saving method to apply thin-walled theory to evaluating hull girder strength which avoided whole ship finite element model.