Three‐dimensional sequential multiscale damage modeling of graphene nanocomposites based on an innovative mixed‐mode interface model

Abstract In this paper, a Lennard‐Jones potential based three‐dimensional cohesive zone model (LJCZM3D) is proposed, and its correctness is verified through various loading combinations of patch tests. Based on MD, the phase‐field model, and LJCZM3D, a three‐dimensional sequential multiscale damage modeling approach for graphene reinforced epoxy nanocomposites is established. The MD simulations are employed to calibrate the parameters of LJCZM3D. Additionally, a 3D graphene‐reinforced epoxy RVE model is developed using a complex Python program. The process involves randomly placing graphene in 3D space, identifying and extracting graphene elements, inserting zero‐thickness cohesive elements on both sides of the graphene, and applying 3D periodic boundary conditions. Thereafter, the phase field damage model and LJCZM3D are used to simulate the damage of epoxy resin and the mechanical behavior of the graphene‐epoxy interface, respectively. Finally, the effects of graphene volume fraction, aspect ratio, orientation, and surface buckling on the mechanical performance of the 3D RVE model are analyzed through a detailed parameter study. Highlights A new 3D Lennard‐Jones potential‐based cohesive zone model is proposed. A 3D sequential multiscale damage modeling approach is established. Extensive MD simulations are employed to obtain the key parameters of the model. The model is implemented and validated through the development of the UMAT subroutine. The influences of several graphene morphological factors are investigated.