Frequency dependent viscoelastic properties of porcine brain tissue

Brain tissue is vulnerable and sensitive, predisposed to potential damage under complicated loading conditions. Its material properties have been investigated, but the characterization of its viscoelastic properties is currently limited. The aim of this study was to investigate the viscoelastic properties of brain tissue. Porcine brain samples, dissected ex vivo in the coronal plane, were tested under compression using dynamic mechanical analysis over a range of frequencies between 0.1 and 35 Hz. Indenters with varying diameters of 8, 12 and 16 mm were used to study the effect on viscoelastic properties under a sinusoidally varying displacement with varying mean displacements (10%, 15% and 20% of a specimen height). As the indenter size increased, the storage and loss stiffness significantly increased (p < 0.05). The storage stiffness decreased significantly as the mean displacement decreased (p < 0.05). The average storage modulus was found to be 8.09 kPa and the average loss modulus was found being 4.85 kPa. Frequency dependent viscoelastic properties of brain are important to improve the accuracy in the computational modelling of the head to develop the prediction of brain injuries.