Theoretical Analysis of New Rheometers

The strain and stress distributions in the sample contained in two new rheometers, the Orthogonal Rheometer and the Balance Rheometer, are discussed. In these rheometers we can measure the complex modulus as the constant force acting on the circular plate (the Orthogonal Rheometer) or as the constant torque acting on the rotational driving shaft (the Balance Rheometer). Although our discussion is restricted to linear viscoelastic materials, any special constitutive equation does not need to be used. The driving torque for the steady rotational motion of the apparatus is also calculated.