PSI - Issue 31

R. Balokhonov et al. / Procedia Structural Integrity 31 (2021) 58–63 R. Balokhonov et al. / Structural Integrity Procedia 00 (2019) 000–000

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3. Three dimensional analysis Materials are three-dimensional in nature. Ceramic particles (Figs. 1 b and c) are very similar in their shape to chip stones. That is why assuming the scale invariance of the natural mechanical frag-mentation we propose a technique for computer simulation of three-dimensional structures of materials with reinforcing particles of complex irregular shapes observed in the experiments. 3D camera shooting of stone surfaces was performed to transform the real stone shapes into their three-dimensional finite-element models (Fig. 4). 3D microstructure models of metal-matrix composites and composite coated materials were created by random distribution of the stone-particles in micro volumes to satisfy the required volume fraction of the particles.

Fig. 4. Numerical models of chip stones – ceramic particles.

The three-dimensional computational analysis fully supports the conclusions made on the results obtained by the plane strain calculations. Numerical simulation of cooling the composite RVE with a single boron carbide particle embedded into the Al6061T6 matrix are shown in Fig.5 as an example. Volume fraction of the boron carbide material is 10%. Plastic deformation localizes around the particle (Fig.5a) in the local regions of the matrix material experiencing bulk compression (Fig.5b), with the maximum value of the plastic strain localization being observed near the particle corners. Bulk tension regions in the matrix locate at a certain distance from the particle and near the interfacial concavities of the matrix into the particle. There is no plastic deformation of the aluminum in these regions. Particle material experiences bulk compression during cooling of the composite, with the maximum stress concentration being observed near the concavity (Fig 5c).

Fig. 5. Cooling induced residual strains and stresses in composite RVE with the particle shown in Fig. 4a. Plastic strain localization % (a) and pressure (Mbar) in the matrix (b), pressure (Mbar) in the particle (c).