【摘要】 断裂破坏是海工结构主要的失效模式之一。对船用灰铸铁构件的裂纹扩展和断裂行为进行模拟研究，对于预防船体设备脆性破坏和结构安全性有重要意义。传统连续介质力学方法在模拟破坏时存在先天不足，而新兴的近场动力学方法（Peridynamics,PD）已证实能模拟材料中裂纹自发的萌生和扩展。本文通过修正PD的长程力尺寸效应和边界效应问题，并根据临界能量释放率推导出对应的裂纹损伤扩展准则，提出一种改进的PD方法。通过薄板的连续变形和破坏实例验证它的准确性，并研究不同预制裂纹灰铸铁构件的裂纹扩展现象。结果表明，改进的PD方法计算结果与试验的裂纹扩展结果吻合较好，其用于预测分析船用灰铸铁构件从连续体到非连续体的整个破坏过程是可行的。更多还原

【Abstract】 Fracture failure is one of the major failure modes in offshore structures. It is significant to investigate the crack propagation and fracture behavior of gray cast iron materials to prevent the brittle failure and structural safety of ship equipment. The classical continuum mechanics has congenital shortcomings in simulating the fracture of solid materials while Peridynamics(PD) theory has been proved capable of simulating the spontaneous initiation and propagation of cracks. In present work, an improved PD method was proposed by considering the long-range force effect and correcting the surface effect of PD, and deducing the corresponding fracture criterion according to the critical energy release rate. The validity and accuracy of the improved model were illustrated by the plate deformation and the brittle plate fracture. Furthermore, the crack propagation of gray cast iron members with different prefabricated cracks was studied. It is indicated that the results of the proposed PD method coincide well with experimental ones, showing that the proposed method is feasible to predict and analyze the entire failure process of marine gray cast iron members from continuum to non continuum.更多还原