Fracture modeling of microscale particles in Discrete Element Method (DEM) simulations poses challenges due to the complexity of capturing grain-scale breakage. Traditional approaches often rely on global stress criteria and neglect strain localization from contact anisotropy. In this study, we investigate intra-granular fracture patterns using thin-section of rock samples and propose a computationally efficient method to mimic the observed localization phenomena. We propose a novel splitting model for 2D polyhedral particles within the open-source DEM framework Yade. The algorithm enables intra-granular fracture along critically stressed contact lines based on normal and shear force components, without requiring additional particle discretization. Validation is performed using the Jointed Cohesive Frictional Particle Model (JCFpm), which simulates brittle failure via a Mohr-Coulomb shear criterion combined with a maximum tensile stress limit [1,2]. Simulations demonstrate that microscale grains exhibit higher effective strength and tend to fracture along contact lines due to anisotropic stress localization. These observations are consistent with prior experimental and numerical studies on grain-scale crushing behavior [3,4]. The proposed method offers a realistic and low-cost approach for capturing grain-scale fracture, making it well-suited for simulating rock fragmentation. By eliminating the need for internal grain discretization, the model enables robust analysis of fracture evolution in polyhedral granular systems and paves the way for studying inter-grain crack propagation under complex loading and contact conditions. REFERENCES [1] V. Šmilauer et al., Yade Documentation 3rd ed., The Yade Project, 2015. [Available online: https://yade-dem.org/doc/] [2] L. Scholtès and F.-V. Donzé, A DEM model for soft and hard rocks: application to rock fragmentation, International Journal of Rock Mechanics and Mining Sciences, 2013, 61: 114–127. [3] T. Imseeh, D. Hurley, and C. Coop, An investigation into the breakage of single sand grains using high-speed imaging, Géotechnique, 2018, 68(3): 179–187. [4] T. Imseeh, D. Hurley, and C. Coop, Effect of contact anisotropy on the crushing strength of aggregates, Granular Matter, 20(3), 57, 2018.