Molecular Mechanical Simulation Of Single Crystal Copper Crack’s Propagation Under Tensile

In the manufacturing production single crystal copper material will inevitably produce micro-cracks,holes and other defects in the structure,which has a great impact on the mechanical properties of materials.Therefore,the crack propagation behavior of a crystalline materials has become a hot research topic in academic today.Based on the software called LAMMPS about molecular dynamics simulation,this article simulate the crack propagation of Single crystal copper plates under different temperatures and initial crack lengths.Combined with the center symmetry parameter method and the potential energy changes comparing and analyzing the system configuration change,dislocation initiation and crack relaxation passivation during the crack propagation.At the same time,the article analyzes the crack initiation load of the single crystal copper plate under different temperatures and different initial crack lengthsIt can be seen from simulating the tensile single crystal copper plate under the different temperatures: When the temperature keeps the normal temperature stage and high temperature stage,with the temperature increasing,the atomic thermal activation increases,the atomic symmetry decreases about the atoms at the tip of the crack,the relaxation increases,and rapidly the crack tip produces the crack initiation.The higher the temperature,the more severely the potential energy changes during the loading system.There is an irregular change in the cryogenic stage about crack initiation load.When the temperature exceed the low temperature,the cracking initiation load decreases with the temperature increasing.When the temperature approaches the melting point,the cracking initiation load tends to the lowest.It can be seen from simulating the crack growth process at the different initial crack lengths.With the initial crack length increasing,the atomic symmetry in the region of the crack tip decreases,causing high stress concentration and the metal bond is more easily fractured,thus accelerating the crack initiation and propagation.As a whole,the crack initiation load decreases with the increase of the initial crack length,and the stability of the system produces unstable changes.