爆破荷载作用下岩石破坏特性的“共轭键”基近场动力学数值模拟研究

近场动力学是一种基于非局部弹性理论的积分形式的无网格数值方法.本文为克服传统近场动力学模型中的固定泊松比问题,建立了"共轭键"基近场动力学模型,实现了岩石爆破破坏特性的近场动力学数值模拟.通过引入"共轭键"转动角度及建立微观和宏观变形能的等效关系,推导了"共轭键"基近场动力学模型中的法向刚度参数及切向刚度参数与宏观力学参数之间的关系.另外,通过对影响域中每根"键"所储存的能量密度与临界"键"能量密度进行对比,判断近场动力学模型中的"键"是否断裂,从而实现裂纹起裂、扩展及连接过程的数值模拟.三个数值算例说明:该模型能有效地模拟岩石爆破破坏特性.数值算例与试验结果对比表明,本文所提出的数值方法可以预测岩石材料的爆破破坏模式及特性.

Numerical simulations of failure characteristics of rock materials under blasting loads using the conjugated bond-pair-based peridynamics

Peridynamics is a new meshfree numerical method based on the nonlocal continuum theory.To overcome the limitation of fixed Poisson’s ratio in the standard bond-based peridynamics,the conjugated bond-pair-based peridynamic model is developed to simulate rock fracture characteristics under blasting loads.The microscopic parameters in the conjugated bond-pair-based peridynamic model can be calibrated by the equivalent relation between the strain energy density at both macroscopic and microscopic scale.In addition,the strain energy stored in the bond is implemented into the fracture criteria to simulate the crack initiation,propagation and coalescence.Three numerical simulation examples show that the present numerical algorithm effectively simulate the failure characteristics of rock materials under the impact loads.It can be found that the present numerical results are in good agreement with the previous experimental observations and the previous numerical predictions,which demonstrate that the proposed numerical method can simulate and predict the failure mode and failure characteristics of rocks subjected to blasting loads.