Modeling and estimation of hole-type flaws on cracking mechanism of SiC ceramics under uniaxial compression: A 2D DEM simulation
Ceramic materials usually contain a large number of hole-type flaws or defects with different characteristics. These flaws are closely related to the fracture failure of materials. Based on the discrete-element method (DEM), three different hole-type flaws were constructed by the super-ellipse equation for SiC ceramics in 2 dimensions. The relationship between the flaw with different characteristics and the failure of SiC ceramic specimens was studied. Further, the crack evolution and the two important parameters (distance from the tip of flaw d and the initiation angle α) to describe the crack initiation position were investigated. Lastly, the stress fields around the hole-type flaw were analyzed. The results show that with the increase of inclination angle of the flaws, the crack initiation position moves from the center position to the flaw tips and the crack initiation angle α increases. Moreover, when the aspect ratio is large and the inclination angle is small, the maximal-tensile stress region around the hole-type flaw is large. Moreover, as the inclination angle increases, the maximal-tensile-stress region moves clockwise around flaws. Finally, the critical dimension of the hole-type flaw affecting the material strength is discussed.
Keywords: Hole-type flaws, Cracking mechanism, Ceramic materials, DEM simulation