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Experimental and numerical analysis of damage fracture mechanics of brain parenchyma

In this paper, a damage and fracture model of brain parenchyma is proposed for a haptic brain surgery simulation. It is assumed that microscopic damage begins by von Mises yield criterion, and the microscopic damage grows rate in proportion to volume strain. Tensile tests with two different strain rate were conducted using porcine brain parenchyma (tensile velocities: 0.1 (mm/s) and 1.0 (mm/s), mean length of specimens: 15 (mm)). Mechanical properties and proposed damage model parameters were identified by solving optimization problem with fitted curves of experimental data at 0.1 (mm/s). The proposed model and identified parameters were verified by comparing the simulation result and experimental data with tensile velocity of 1.0 (mm/s). A conventional damage model, simplified Lemaitre model, was implemented for comparison. Tensile simulations were performed with two models, proposed model and simplified Lemaitre model, with tensile velocity of 0.1 (mm/s). The simulation results were compared with the experimental result. It is confirmed that the proposed model well reproduce damage and fracture mechanics of brain parenchyma, while the simplified Lemaitre model could not well reproduce the ductility.