随机海况下的船体结构疲劳裂纹扩展

Hull structural fatigue crack propagation under random sea state

传统的疲劳问题一般都是采用S—N曲线及Miner累计损伤理论进行的,文章在基于断裂力学的基础上,通过权函数法来计算应力沿裂纹面的非线性效应力强度因子,鉴于船舶在海洋环境中受到载荷的随机性,充分考虑加载次序、过载峰和应力比等对裂纹扩展的影响,给出了船舶结构疲劳裂纹在随机载荷下的扩展寿命的计算过程。

Traditionally, fatigue are generally analyzed by S-N curve and Miner cumulative damage theory. The nonlinear stress intensity factors of the stress along the crack surface are calculated by the weight function method based on the fracture mechanics. In view of the random load for ships in sea state, the impact of load order, peak overload and stress ratio on the crack propagation are fully considered for the calculation of the ship structure fatigue crack propagation life under the random loads.