Apparatus and method for determining the fundamental viscoelastic properties of a material

摘要

A method of determining the fundamental viscoelastic properties of a viscoelastic material includes the steps of imparting a torsional stress in a viscoelastic material; measuring the relaxation of the torsional stress over time and converting the relaxation stress to a representative analog waveform; digitizing the representative analog waveform to produce a representative digital waveform; and, determining the frequency dependant fundamental viscoelastic properties of the material based on the shape of a portion of the representative digital waveform. To facilitate automating the method, the shape of the waveform may be analyzed to detect the start of a test, the end of the test, and whether the test is a valide test. Preferably, the fundamental viscoelastic properties of the test material are determined by converting the torque based amplitudes of the waveform to shear relaxation modulus values, such as by multiplying the torque amplitudes by the geometric form factor of the test material, and then by transforming the shear stress modulus values to frequency dependant fundamental viscoelastic properties through the known Yagii/Maekawa approximation. A related apparatus is also disclosed.