循环载荷下考虑累积塑性影响的含中心穿透裂纹板CTOD研究

裂纹尖端张开位移(CTOD)是评估结构材料韧性以及分析低周疲劳破坏引起的裂纹扩展的重要参量。结合Dugdale模型,以裂纹尖端累积塑性应变为控制参量,提出了一个循环载荷下含裂纹船体板的CTOD计算模型;利用有限元法模拟了裂纹尖端累积塑性应变、平均应力、裂纹长度等相关因素影响;结合最小二乘法拟合出了基于累积塑性塑性应变、平均应力比以及裂纹长度的两阶多项式。研究表明,基于累积塑性应变的CTOD计算模型为正确评估循环载荷下船体板的累积塑性破坏提供了一种新途径。

Research on CTOD for Low-Cycle Fatigue Analysis of Central-through Cracked Plates Considering Accumulative Plastic Strain

Structural components subjected to high cyclic loadings may lead to plastic deformation accumulation and result in fracture failure. The low-cycle failure is the coupling result of accumulative plastic damage and low-cycle fatigue damage. The crack tip opening displacement (CTOD) is one of the important parameters for studying the low-cycle fatigue of plate sustaining large scale yielding. The CTOD value can reflect the ability of material resistance to crack initiation and propagation, and it is an important parameter to evaluate material toughness as well as the main controlling parameter to analyze the crack propagation due to low-cycle fatigue damage.