The numerical calculation of storage and loss compliance from creep data for linear viscoelastic materials

Numerical formulae are given for calculation of storage and loss compliance from the course of the creep compliance for linear viscoelastic materials. These formulae involve values of the creep compliance at times which are equally spaced on a logarithmic time scale. The ratio between succeeding times corresponds to a factor of two. A method is introduced by which bounds for the relative error of those formulae can be derived. These bounds depend on the value of the damping, tan δ. The calculation of the storage compliance is easier with the lower damping values. This calculation involves the value of the creep compliance at time t0=1/ω, and that of its derivative with respect to the logarithm of time in a rather narrow region around t0. In contrast the calculation of the loss compliance is more difficult with the lower damping values. This calculation involves the value of the derivative of the creep compliance with respect to the logarithm of time in a broad interval around t0. © 1969 Dr. Dietrich Steinkopff Verlag