Phase-field modeling of pressure-induced soft tissue rupture with tension-compression asymmetry

Various physiological diseases and injuries, such as stroke or brain tissue concussion, are closely associated with the rupture of blood vessels, so that blood pressure plays an important role in their progression. Predicting the pressure-induced rupture of soft tissue can be challenging, however, due to the mechanical nonlinearity, tension-compression asymmetry, and softness-induced large deformations. A phase-field model (PFM) in the finite deformation regime is thus herein proposed to study the blood pressure-induced rupture, considering the tissue's tension-compression asymmetry and nonlinearity. A staggered scheme is proposed to solve the coupling of the deformation and the phase field problems, and implemented in commercial software. With a proposed regularization of the phase field inside the pressure-induced rupture region, the model's accuracy is first verified in terms of its capability to predict the crack opening displacement, and compare well with direct numerical simulation performed under the assumption of no crack propagation. Pressure-induced rupture in soft brain tissue with multiple initial tears (seen as crack-like defects) is subsequently examined in detail. This proposed PFM further incorporates blood transport during the rupture process, showing potential in predicting the realistic behavior of soft tissue.