船舶结构疲劳评估设计波法

Research on the design wave approach for the fatigue assessment of ship structures

以散货船船舯内底与底边舱斜板折角处节点为例,对船舶结构疲劳评估的设计波法进行研究.论述了设计波法的基本原理,给出了确定设计波的流程。通过分析该节点的受力情况,确定5个控制载荷参数及设计波参数。以谱分析法得到的参考应力范围为目标值,对5个控制载荷参数对应的设计波作用下的节点应力范围结果进行回归分析,从而得到了用于疲劳评估的设计波组合,并利用该方法对1艘散货船的船舯内底与底边舱斜板折角处的节点进行了计算。结果显示,设计波法与谱分析法的结果吻合较好,计算量大幅减少。

The design wave approach for the fatigue assessment of ship structures is studied. Principles of the design wave approach are discussed and the procedures for the determination of the design wave are given. Five dominant loads and corresponding design wave parameters are identified by analyzing the loads acting on the structural detail of the knuckle between inner bottom and hopper sloping plating. A combination of the design waves for fatigue assessment is achieved by fitting the stress ranges of the structural details under the five design waves to the reference stress ranges obtained from the spectral fatigue analysis. As an example, the fatigue assessment of the structural detail of another bulk carrier is performed by using the combination of the design waves. The results have a good agreement with those from the spectral fatigue analysis and the workload is reduced substantially.