Computational modeling and simulation of spall fracture in polycrystalline solids by an atomistic-based interfacial zone model

Liqiang Lin, Xiaowei Zeng
2015 Engineering Fracture Mechanics  
The focus of this work is to investigate spall fracture in polycrystalline materials under high-speed impact loading by using an atomistic-based interfacial zone model. We illustrate that for polycrystalline materials, increases in the potential energy ratio between grain boundaries and grains could cause a fracture transition from intergranular to transgranular mode. We also found out that the spall strength increases when there is a fracture transition from intergranular to transgranular. In
more » ... ddition, analysis of grain size, crystal lattice orientation and impact speed reveals that the spall strength increases as grain size or impact speed increases. To calculate the potential energy for a crystalline solid, the Cauchy-Born rule is employed in the proposed atomistic-based interfacial zone model. The so-called Cauchy-Born can describe the material behavior from atomistic information and is widely used as a standard method in continuum mechanics [21, 22] . It refers to the following procedure: let x denote the spatial position of a material point X at the time t, thus the local continuum deformation gradient is given by . Since in a given element e(e = 1, ..., n elem ), the deformation gradient, F e , is a homogeneous tensor, the relative deformed bond vector r i in a unit cell results from the corresponding related undeformed atomic bond vector R i can be defined as: (1)
doi:10.1016/j.engfracmech.2015.05.039 pmid:26435546 pmcid:PMC4587396 fatcat:6bgwrnbvqjaffldihvwuv6teem