A Visco-Hyperelastic Constitutive Model for Describing the Mechanical Behavior of the Spinal Cord White Matter Under Various Strain Rate Conditions

The mechanical behavior of the white matter is important for estimating the damage of spinal cord during accidents. In this study, we conduct uniaxial tension testing in vitro of spinal cord white matter under extremely high strain rate conditions (up to 100/s-1). A new visco-hyperelastic constitutive law for modeling the strain rate-dependent behavior of the spinal cord white matter was developed. A set of material constants was obtained using a fitting algorithm to match the uniaxial tension experimental data with various strain rates. These new data in terms of mechanical response at high strain rate provide insight into the spine injury mechanism caused by high-speed impact. Moreover, the proposed constitutive model will allow researchers to perform more realistic finite element modelling and simulation of spinal cord injury damage under various complicated conditions.