There are two major techniques for determining the viscoelastic properties in general. One is the dynamic retardation measurement for sinusoidal input and the other is the static measurement under constant strain-rate. In the pervious paper, the authors developed a Prony series approximation technique for the determination of viscoelastic functions from dynamic response of materials utilizing the random searching method. The authors develop a new approximation algorithm for the determination of viscoelastic material functions by a Prony series using data obtained under constant strain-rate test. The technique proposed enables, 1) to eliminate complicated procedures, 2) to determine the coefficients in the Prony series in high accuracy avoiding the ambiguity in sign change. In order to evaluate the effectiveness of the technique, the authors determined not only the relaxation modulus but the creep compliance of an epoxy resin successfully in high accuracy standing on the concept of pseudo-elasticity.
