Fracture modeling of CNT/epoxy nanocomposites based on phase-field method using multiscale strategy

The computational modeling of fracture, particularly in structures with complex crack topologies, remains challenging due to significant computational costs, especially in simulating two- and three-dimensional brittle fracture. This study presents an efficient phase-field model to address these challenges. By leveraging the user (UMAT) subroutine in ABAQUS and establishing an analogy between the phase-field evolution law and the heat transfer equation, the method efficiently tackles complex fracture problems. The model is verified through analysis of typical 2D and 3D fracture benchmarks with different failure modes, demonstrating accuracy and efficiency compared to experimental and numerical data. Additionally, the model is applied to explore brittle fracture in carbon nanotubes (CNTs)/epoxy nanocomposites, revealing insights into the impact of CNT weight fraction on fracture phenomena prediction. The incorporated CNTs in the matrix are considered uniformly dispersed and randomly oriented. Overall, the developed model and computational implementation show promise for meeting the requirements of structural-level engineering practices.