  The mechanical characterization of brain tissue at high loading velocities is
vital for understanding and modeling Traumatic Brain Injury (TBI). The most
severe form of TBI is diffuse axonal injury (DAI) which involves damage to
individual nerve cells (neurons). DAI in animals and humans occurs at strains >
10% and strain rates > 10/s. The mechanical properties of brain tissues at
these strains and strain rates are of particular significance, as they can be
used in finite element human head models to accurately predict brain injuries
under different impact conditions. Existing conventional tensile testing
machines can only achieve maximum loading velocities of 500 mm/min, whereas the
Kolsky bar apparatus is more suitable for strain rates > 100/s. In this study,
a custom-designed high rate tension device is developed and calibrated to
estimate the mechanical properties of brain tissue in tension at strain rates <
90/s, while maintaining a uniform velocity. The range of strain can also be
extended to 100% depending on the thickness of a sample. The same apparatus can
be used to characterize the dynamic behavior of skin and other soft biological
tissues by using appropriately sized load cells with a capacity of 10 N and
above.
