Brain injury resulting from exposure to blast continues to be a significant problem in the military community, often leading to death or long term disability. The presence of high frequency energy content in pressure waves generated in explosive blasts necessitates understanding the transmissibility and damping characteristics of skull bone. Current finite element models (FEM) of the skull do not include material damping and therefore fail to capture the correct attenuation spectrum or rate dependency of skull bone.

Cylindrical through-the-thickness specimens of skull bone were obtained from ten adult (55 ± 10 years old) male post-mortem human surrogates. A test apparatus was developed to apply cyclic loading to potted cores at frequencies ranging from 1 to 50 kHz using a piezoelectric shaker. High bandwidth transducers were used to record accelerations and forces at the boundary. A lumped mass model was optimized to match the recorded boundary conditions.

This paper reports composite material properties of the skull as a frequency dependent complex modulus. The calculated material loss tangent was distributed in a log-normal fashion and ranged from 0.027 to 0.194 (95 % CI). A generalized Maxwell model, represented using a Prony series has been developed and the model parameters have been reported.