A method for identifying the damage thresholds of porcine brain under low- and medium-strain rates

Abstract

Predicting the damage thresholds of brain tissue is crucial for preventing permanent pathological changes and developing therapeutic interventions. This study presents a method for determining the damage thresholds of porcine brain tissue using experimental data and theoretical modeling. By conducting loading and unloading experiments on porcine brain samples, the mechanical responses under varying strain rates and maximum compressive strains are analyzed. A constitutive model incorporating viscoelastic behavior, the Mullins effect, and residual deformation is proposed, effectively characterizing the mechanical properties of the brain tissue. By calculating the ratio of damage-induced dissipated energy and viscoelastic dissipated energy, the extent of damage under different maximum compression strain is quantified. The method’s reliability is validated through examining changes in modulus between the stress–strain curves obtained from the first and second loadings. At a strain rate of 0.3$s^{-1}$, the mild damage strain threshold is estimated to be 0.2 – 0.3, while the moderate-to-severe damage threshold falls within 0.3 – 0.4, aligning closely with values reported in the literature. Additionally, the damage strain thresholds at 200$s^{-1}$ are consistent with those at 0.3$s^{-1}$. The corresponding stress threshold at 200$s^{-1}$ranges from 5.9 to 11.4 kPa for mild damage and from 11.4 to 22.8 kPa for moderate-to-severe damage. The findings of this study are expected to contribute to brain damage prediction.