PSI - Issue 68

Xingling Luo et al. / Procedia Structural Integrity 68 (2025) 694–700 Xingling Luo et al. / Structural Integrity Procedia 00 (2025) 000–000

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was implemented in simulations with models with real, simplified, and random inclusions. Additionally, a layer around the inclusion was introduced to represent the interface between the matrix and the graphite particles in the models with real and simplified morphology to reduce the edge effect. The thickness of the cohesive interface was set to zero. All unit cells and RVEs were modelled with triangular finite elements (3-node linear plane strain triangle – CPE3) in ABAQUS as quadrilateral elements would generate sawtooth particle boundaries, causing stress concentrations (Zhang et al., 2018). The main details of the models are summarised in Table 3.

Table 3. Model details.

Volume fraction of graphite (%) 7.1 - 11.2%

Element type

Analysis type Dynamic explicit

Domain length

Mesh size

Loading

Boundary conditions

Software

Abaqus

Tension

0.1 mm - 0.5 mm

Average 2 µm

Triangular (CPE3)

fixed & displacement on opposite sides and PBCs or free on other sides

2.2. Constitutive relations The graphite particle and the matrix were assigned elastoplastic behaviours. The detailed constitutive relations of graphite and matrix phases are given in (Luo et al., 2024), with the JC damage parameters in (Luo et al., 2024a). The cohesive-zone modelling method employed in this study used the traction-displacement relations to describe the onset and growth of damage along the inclusion-matrix interface [121]. 3. Results In this section, a comparison between the model predictions on crack initiation and propagation is presented (Fig. 3).

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Fig. 3. Crack paths and von Mises stresses under tensile loading for four types of models (N - nodular graphite; V - vermicular graphite; F - flake graphite; R - real morphology; R i – (i=1, 2, 3, 4) - random morphology for different statistical realisations of microstructure).