

Dynamic Shear Behavior of Soft Biological Tissues
Abstract
The characterization of the mechanical behavior of soft biological tissues has been an active area of research for many years. In particular the determination of the mechanical properties of brain tissue, especially at high strain rates, has become of considerable importance due to the increased incidence of traumatic brain injury due to automotive, sports and military accidents. Compressive response of soft biological tissues at high strain rates was determined using a Kolsky compression bar. The high-rate elastic modulus was found to be significantly greater than the shear modulus. An analysis indicates that modulus discrepancy is due to very small perturbations in the radial strain in the Kosky-bar experiments due to factors such as non-ideal slippage at the specimen-bar interface or transverse inertia. The analysis also shows that the discrepancy is a function of the ratio of the bulk modulus to the shear modulus, where the shear modulus can be orders-of-magnitude lower than the bulk modulus in soft tissues. The analytical results were verified by experiments using a lightly cross-linked poly(dimethyl siloxane) based polymer gel, which was developed with similar mechanical properties to soft biological tissues, where the modulus of the gel can be adjusted via the amount of low molecular weight diluent in the synthetic gel.
Keywords
high-rate response; soft biological tissuesText