循环载荷下船体圆孔板塑性累积与致断特性

Plastic accumulation and fracture characteristics of hull plates with circular holes under cyclic loading

[目的]为了解初始挠度形状对循环载荷下船体圆孔板塑性累积特性的影响,采用有限元软件ABAQUS对不同柔度系数和开孔尺寸的圆孔板,开展轴向循环载荷下的非线性弹塑性大挠度数值模拟。[方法]重点研究以第一阶屈曲模态和常用初始挠度公式构造初始挠度形状时,轴向循环载荷下圆孔板的塑性累积及其致断特性。[结果]研究表明,以常用初始挠度公式作为初始挠度形状的圆孔板,在相同循环载荷幅值下的塑性累积较第一阶屈曲模态缓和。同时,循环载荷幅值较小时,以第一阶屈曲模态作为初始挠度形状的圆孔板在相同载荷下的致断循环次数少于以常用初始挠度公式构造初始挠度形状的情况,但差异随载荷幅值的增大而减小。[结论]不同的初始挠度形状对圆孔板塑性累积与断裂起始的影响取决于柔度系数、开孔尺寸以及循环载荷幅值。

[Objectives]This study seeks to grasp the effects of the initial deflection shape on the plastic ac-cumulation characteristics of hull plates with circular holes under cyclic loading.[Methods]Finite element software ABAQUS is used to carry out the nonlinear elastic-plastic large deflection numerical simulation of hull plates with circular holes of different slenderness ratios and perforation sizes under axial cyclic loading.The plastic accumulation and fracture characteristics of the plates under axial cyclic loading are studied with the initial deflection shape made by the first-order buckling mode and commonly used initial deflection for-mula respectively.[Results]The plastic accumulation of plates with the initial deflection shape made by the initial deflection formula is relatively moderate.When the axial cyclic loading amplitude is relatively low,the number of fracturing cycles of plates with the initial deflection shape made by the first-order buckling mode is relatively small,but the difference decreases as the amplitude increases.[Conclusions]The influence of dif-ferent initial deflection shapes on the plastic accumulation and fracture characteristics of plates with circular holes depends on the slenderness coefficient,perforation size and axial cyclic loading amplitude.