PSI - Issue 52

Thi Ngoc Diep Tran et al. / Procedia Structural Integrity 52 (2024) 366–375 Thi Ngoc Diep Tran/ Structural Integrity Procedia 00 (2019) 000 – 000

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4.3. Models with rotated particle corners As observed in section 4.2, long and horizontally oriented reinforcement particles have caused cracks at various locations in the models. For this reason, the effect of particles with sharp corners is investigated by rotating the corners of different particles in the model from micrograph (compare model 1 in Fig. 8 versus model 1 in Fig. 10) and in the model with sharp-edged particles (compare model 5 in Fig. 8 versus model 2 in Fig. 10), so that they are oriented perpendicular to the tensile loading. During loading, these sharp edges are under tension. The rotated particles are marked with circles. As expected from the results in Fig. 10, cracks develop where the corners are rotated, since they define the sites of stress concentration under tension, which leads to crack formation. Since more crack formations occur in the new models, their tensile strengths must be lowered compared to the models without rotated particle corners as shown in Fig. 11.

Fig. 10. Models with rotated particle corners, the rotated particles are in the circles.

Fig. 11. Tensile strengths of models with rotated particle corners (models in Fig. 10) versus without rotated particle corners (models 1 and model 5 in Fig. 8). 5. Conclusions The failure of the particle-reinforced composites under tensile loading is investigated in the presented paper. The effect of particle shape, size, and orientation on crack propagation is studied using 2D finite element models of the particle-reinforced composite, where the particle is much stiffer than the matrix. From the original model obtained from the real material microstructure, various structure realizations are created for each particle parameter variation and compared with each other. This study brings forth the following major conclusions: • Varying the particle geometry cause different crack propagations. Crack formation is characterized by the detached particle-matrix interface and then growing around the particle. Particle with higher aspect ratio as well as cluster of large particles may deflect the crack, and therefore it deviates from its path. • Crack initiation tends to start at long and horizontally oriented particles by tensile loading in the vertical direction. This observation occurs particularly with particles whose sharp corner is oriented perpendicular to the tensile