Molecular dynamics simulation studies on mechanical properties of standalone ligaments and networking nodes, a connection to nanoporous material
HM Liu and LJ He and N Abdolrahim, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, 26, 075001 (2018).
Structurally, nanoporous (NP) materials can be regarded as a network of interconnected nanowires. In this study, molecular dynamics simulations are employed to investigate the deformation behavior of individual ligaments and isolated three-fold nodes, which are the two main structural components in NP materials. The shear strain tensor analysis is used to quantitatively differentiate deformation mechanisms accommodating strain among structures and capture onset of necking during stretching. Ligaments and nodes behave differently in both elastic regime and plastic regime. Our results suggest that node structure is brittle with low stiffness and yield strength, similar to NP structure, while ligament structure is ductile and exhibits high stiffness and yield strength. In isolated three-fold nodes and NP network structure, we observed similar deformation behavior exists; formation of pyramidal shape defects consisted of twinning partials and Shockley partials on different 111 planes at node region. The similarity of mechanical properties and deformation behavior between node structure and NP structure indicates that the role of node components is substantially significant in controlling structure- property relationships of NP materials. Enhancing node components is proposed as a potential method for improving mechanical properties of NP materials.
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