To predict complex crack propagation behavior in composite materials, we present a virtual element method (VEM)-based cohesive fracture model [1]. Crack propagation within individual constituent phases and crack interactions, such as the coalescence of multiple cracks and branching from one phase into another, are effectively captured using adaptive element splitting within a polygonal discretization. A crack propagation direction is evaluated using the maximum principal stress criterion, and polygonal elements are adaptively split along the computed crack path. Then, cohesive elements are inserted along the split edges to explicitly describe the crack surface. Due to the flexibility of element shapes in VEM, mesh modification events such as element splitting are efficiently and consistently handled while maintaining high mesh quality. For the cohesive constitutive relationship, the Park-Paulino-Roesler (PPR) cohesive fracture model [2] is modified to produce a highly convex softening curve comparable to that of the bilinear softening model commonly used for quasi-brittle materials. To demonstrate the accuracy and robustness of the proposed computational framework, three numerical examples are presented: the uniaxial tension test of a single fiber-matrix system, the three-point bending test of a mortar beam with granite inclusions, and the three-point bending test of a concrete beam at the mesoscale incorporating realistic aggregate shapes. The computational results, including global load-displacement curves and crack evolution patterns, are compared with the numerical and experimental data reported in the literature, showing good agreement. REFERENCES [1] H. Choi, H. Chi, K. Park and G.H. Paulino, Adaptive virtual element method with a modified Park-Paulino-Roesler (PPR) cohesive fracture model for complex crack propagation in heterogeneous materials, in preparation. [2] K. Park, G.H. Paulino and J.R. Roesler, A unified potential-based cohesive model of mixed-mode fracture. Journal of the Mechanics and Physics of Solids, Vol. 57(6), pp. 891-908, 2009.