The concrete armour units used widely for harbour breakwaters are largely made with unreinforced concrete. There therefore is a risk, especially from dynamic loading as units may become loosened or dislodged or rock during storm action, that fracturing of units as seen in lower photo from Crescent City Breakwater in California, could compromise the protective armour layer.
Solidity employs a validated 3D tensile and shear failure fracture model that can be applied to investigate such problems.
Guo, L., Latham, J. -P., & Xiang, J. (2014). Numerical simulation of breakages of concrete armour units using a three-dimensional fracture model in the context of the combined finite-discrete element method. Computers and Structures, 146, 117-142. doi.org/10.1016/j.compstruc.2014.09.001
Guo, L., Latham, J. -P., Xiang, J. & Izzuddin. (2015). A numerical investigation of mesh sensitivity for a new three-dimensional fracture model within the combined finite-discrete element method. Engineering Fracture Mechanics, EFM-D-15-00399R1. doi.org/10.1016/j.engfracmech.2015.11.006