Length scales in the tear resistance of soft tissues and elastomers: a comparative study based on computational models

Abstract Fracture toughness describes a material’s ability to resist failure in the presence of defects. In case of soft biological tissues, a reliable determination and interpretation of the fracture properties is essential to estimate the risk of fracture after clinical interventions. Here we perform a comparative computational study between soft biological tissues and compliant elastomers to discuss the influence of material non-linearity on the crack tip nearfield. Using detailed finite element simulations, singular near-tip stress fields are obtained, and a so-called nonlinear region is identified. Additional focus is put on the effect of material nonlinearity on the phenomenon of elastic crack blunting, by analysing the deformed crack profile and extracting a radius of curvature at the tip. Through concepts of traditional fracture mechanics, we identify the size of the process zone and nonlinear elastic zone in biological tissues, juxtaposed with that of elastomers, demonstrating the limitations of the traditional metrics in capturing the remarkable defect tolerance of this highly nonlinear material class.