小水线面双体船连接桥结构多轴疲劳分析方法

A multi-axial fatigue assessment method for the connecting bridge of a small waterplane area twin hull craft

针对小水线面双体船(SWATH)连接桥处承受多轴应力这一现象,开展了此结构的多轴疲劳分析方法研究.在传统S-N曲线法的基础上利用基于Tresca准则的等效应变方法和Brown-Miller临界面法,给出了2种多轴疲劳评估的简化方法,推导出了每种方法的疲劳寿命计算公式.参照规范工况采用提出的新方法对某SWATH进行了疲劳强度评估,并将计算结果和现有规范方法进行了比较,结果表明多轴应力的影响不容忽略.

The connecting bridge structure of a small waterplane area twin hull（SWATH） craft is subject to complex sea loads and experiences multi-axial stress in the actual service process.In view of this phenomenon,multi-axial fatigue analysis for the connecting bridge structure of SWATH was carried out.Equivalent strain method based on Tresca yield criterion and Brown-Miller critical plane model were used to develop simplified multi-axial fatigue analysis using a stress life（S-N） curve theory,and the formulas of fatigue life calculation for simplified multi-axial fatigue were derived.As an example,these developed methods were used to calculate the fatigue life of SWATH based on the loading conditions of rules given by ship classification societies,and results were compared with those methods of current rules.The results show that the effect of multi-axial stress can not be neglected.