基于冰载荷数值模拟的极地船舶冰致疲劳计算

Fatigue Assessment of Polar Ship Induced by Ice Loading with Numerical Calculation

极地船舶在冰区航行时,其船体结构所受冰载荷经常会出现逐渐加载之后断裂卸载,再逐渐加载的周期性特点。这种往复循环的冰载荷与极地的低温环境共同作用,会加剧船体结构的疲劳问题。由此,为了准确评估冰载荷引起的船体结构疲劳损伤,以一艘极地物探船为研究对象,采用有限元方法获得船体上的冰载荷曲线,通过线性转化和Goodman修正等方法将该载荷曲线转化为疲劳计算所需的应力循环,并基于S-N曲线和疲劳线性累计损伤理论对该极地物探船进行冰致疲劳损伤评估。计算结果表明:该极地物探船冰带区域的舷侧纵桁与横舱壁交界位置最易产生冰致疲劳,冰载荷引起的极地物探船冰带区域关键节点的疲劳损伤满足设计要求;冰载荷引起的极地船舶疲劳损伤不可忽略。

When a polar ship sails in an ice region,the ice loading on the hull structure often appears to be gradually loaded,then unloaded with ice broken,and then gradually loaded.This cyclic ice loading and the polar low temperature environment are likely to induce the fatigue problem of hull structure.Therefore,it is necessary to assess the fatigue damage of the hull structure caused by the ice loading.A polar geophysical prospecting ship is taken as the research object.The ice loading time history on the hull is obtained by the finite element method,and then the loading time history is converted into the stress cycles for fatigue calculation by methods such as linear conversion and Goodman correction.The ice-induced fatigue damage of polar geophysical prospecting ships is assessed based on S-N Curve and linear cumulative fatigue damage theory.It can provide reference for assessment of ice-induced fatigue of polar ships.