Analysis of Stress Relaxation and Creep Curves for a Log‐Normal Distribution of Relaxation Times

Abstract

AbstractA procedure to determine the characteristic parameters of a log‐normal distribution of relaxation times, both for stress relaxation and creep tests, is presented. The method is based on the use of either the normalized stress relaxation or creep functions and their first derivatives. Furthermore, the limiting stress or strain can be obtained directly from the experimental data. Finally, the procedure developed is applied to actual stress relaxation curves reported for aluminum and polysulphide rubber and the results are compared with those obtained by approximate methods, based on the use of the error function.