Numerical Investigation of the Fracture Properties of Pre-Cracked Monocrystalline/Polycrystalline Graphene Sheets

• Published in: Materials Vol. 12; no. 2; p. 263
• Main Authors: Li, Xinliang, Guo, Jiangang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 15.01.2019; MDPI
• Subjects: Bond strength; Chemical vapor deposition; Defects; Energy; Fracture toughness; grain boundary; Graphene; Heat treating; Mechanical properties; Mechanics; Molecular structure; molecular structure mechanics; polycrystalline graphene; Polycrystals; Researchers; strain energy per unit area; Stress concentration; Theory; Timoshenko beams; strain energy per unit area; fracture toughness; polycrystalline graphene; grain boundary; molecular structure mechanics
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma12020263

The fracture properties of pre-cracked monocrystalline/polycrystalline graphene were investigated via a finite element method based on molecular structure mechanics, and the mode I critical stress intensity factor (SIF) was calculated by the Griffith criterion in classical fracture mechanics. For monocrystalline graphene, the size effects of mode I fracture toughness and the influence of crack width on the mode I fracture toughness were investigated. Moreover, it was found that the ratio of crack length to graphene width has a significant influence on the mode I fracture toughness. For polycrystalline graphene, the strain energy per unit area at different positions was calculated, and the initial fracture site (near grain boundary) was deduced from the variation tendency of the strain energy per unit area. In addition, the effects of misorientation angle of the grain boundary (GB) and the distance between the crack tip and GB on mode I fracture toughness were also analyzed. It was found that the mode I fracture toughness increases with increasing misorientation angle. As the distance between the crack tip and GB increases, the mode I fracture toughness first decreases and then tends to stabilize.