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拓展虚内键(Augmented Virtual Internal Bond,AVIB)是基于虚内键理论的一种多尺度力学模型,采用Xu-Needleman势函数来描述虚内键中的能量势,将脆性材料的断裂问题归结为虚内键能量势的问题,由于势函数中已经包含了材料的微观断裂机理,不需要额外的断裂准则,因此在模拟脆性材料断裂方面具有显著的优势。采用AVIB模型对多裂纹简支梁在冲击荷载作用下裂纹的扩展过程进行了数值模拟,模拟结果表明当冲击点荷载达到最大值时,梁中裂纹开始起裂,对称双裂纹梁形成两条主裂纹并同时向冲击点扩展,梁呈对称破坏模式;非对称双裂纹以及对称多裂纹梁均形成一条主裂纹,并向冲击点扩展,直到梁发生断裂,呈非对称破坏模式。
Augmented Virtual Internal Bond (AVIB) is a multi-scale mechanical model based on the virtual internal bond theory. The energy potential in the virtual internal bond is described by using the Xu-Needleman potential function. The fracture problem of brittle materials is summarized as Since the potential function contains the microscopic fracture mechanism of the material and does not require additional fracture criterion, it has significant advantages in simulating the fracture of brittle material. The AVIB model was used to simulate the propagation of crack under multi-cracked simply supported beams under impact loads. The simulation results show that when the load reaches the maximum point, the crack begins to crack and the symmetrical double-cracked beam forms two main The crack propagates to the impact point at the same time. The beam presents a symmetrical failure mode. The asymmetric double crack and the symmetrical multi-crack beam form a main crack and extend to the impact point until the beam breaks down and presents an asymmetrical failure mode.