One of the most frequently used experimental methods for
characterizing the viscoelastic material properties of soft
tissue is the dynamic oscillation experiment. In this test,
small periodic strains at varying frequencies are applied to
the sample and the stress response is recorded. These smallamplitude
oscillatory tests are commonly performed in shear
using a rheometer. In rheological shear measurements, a
cylindrical viscoelastic sample is placed between the plates of
a rheometer, and some amount of compression is applied
first to ensure full contact between the sample and the plates
and hence to reduce the slippage. Subsequently, small oscillatory
shear is applied to the sample in the linear viscoelastic
range (LVR) to measure its torque response. The shear stress
is then calculated from the measured torque response based
on the sample geometry. Finally, the shear stress is divided
by the shear strain in frequency domain to obtain two shear
moduli at each frequency: one in-phase with the applied