含中心穿透裂纹加筋板低周疲劳裂纹扩展研究

Study on Low Cycle Fatigue Crack Propagation of Stiffened Plate with Central Penetration Crack

针对船舶大型化发展过程产生的船体结构疲劳强度问题,使用有限元分析软件ABAQUS中节点释放裂纹扩展方式对不同工况下含裂纹加筋板的应力、应变场进行分析。以AH32钢材为原材料开展了含裂纹缺陷加筋板的低周疲劳裂纹扩展实验研究,利用实验结果对有限元分析结果进行合理性分析。采用拉伸引伸计测定裂纹张开位移,以高清摄像头采集裂纹扩展全过程,并通过实验方式对裂纹扩展速率与裂纹张开位移的关系展开讨论。引入裂纹扩展速率与裂纹张开位移关系曲线,对加筋板的裂纹扩展特性进行分析。结果证明,加筋板裂纹扩展特性与应力比、最大外载荷、过载比、加强筋刚度比有着密切联系。同时,引入的裂纹扩展速率与裂纹张开位移关系曲线能更为直观地反应加筋板在裂纹扩展过程中的各项特性。

In order to introduce the fatigue problem of hull structure caused by large-scale development of ships,finite element software ABAQUS was used to simulate the stress field and strain field of stiffened plate under different working conditions.Crack propagation was controlled by node release method.The rationality of the numerical simulation was verified by a series of experiments on stiffened plates made of AH32 material.The crack opening displacement was measured by an extensometer,and the whole process of crack propagation was collected by a high-definition camera.The relationship between crack propagation rate and crack opening displacement was discussed.The crack propagation rate and crack opening displacement curve were introduced to analyze the characteristics of stiffened plates during crack propagation.The results showed that the crack propagation characteristics of the stiffened plates are closely related to the stress ratio,the maximum external load,the overload ratio,and the stiffener stiffness ratio.The relationship between the crack propagation rate and the crack opening displacement can be more intuitively reflected in the crack propagation process.