二轴低周疲劳载荷下船体裂纹板累积塑性与断裂性能分析

Analysis of accumulative plasticity and fracture behavior of hull cracked plates subjected to biaxial low-cycle fatigue loading

恶劣海况中在多轴高应力、低循环交变载荷作用下,船体结构不仅会出现多轴低周疲劳破坏,而且还存在着明显的累积塑性破坏。应变强度因子ΔK_(ε)、J积分是评估船体结构二轴低周疲劳裂纹扩展断裂失效的重要控制参数。本文重点研究了二轴低周疲劳载荷作用下船体裂纹板的累积塑性规律以及二轴低周疲劳裂纹断裂参数。利用有限元数值模拟分析了二轴低周疲劳载荷下不同平均应力、应力幅和二轴应力比等相关因素对应变强度因子、J积分的影响,为正确评估船体裂纹板二轴低周疲劳裂纹扩展断裂行为提供了基础。

Not only does the multiaxial low-cycle fatigue damage of a hull structure appear,but also the obvious accumulative plastic failure occurs when the hull structure is subjected to the multiaxial high stress and low-cyclic load in severe extreme sea conditions.The strain intensity factor(SIF)ΔK_(ε) and J-integral are important key parameters to evaluate the multiaxial low-cycle fatigue crack propagation failure of ship hull structures.In this study,the accumulative plasticity and fracture parameters of hull cracked plates subjected to the biaxial low-cycle fatigue loading were studied.The influence of different mean stress,stress amplitudes and biaxial stress ratios on strain intensity factor and J-integral under the biaxial low-cycle fatigue load was analyzed by finite element numerical simulation,which provides the basis for correctly evaluating the propagation and fracture behavior of hull cracked plates subjected to the biaxial low-cycle fatigue loading.