Creep Modelling of a Material by Non-Linear Modified Schapery’s Viscoelastic Model

Abstract

This research work aims at modeling the creep behavior of a material by a non-linear schapery's viscoelastic model. We started with analytical part where three powerful methods of creep modeling have been developed and compared. That is the Heaviside, the Nordin and Varna and lastly our own proposed methods. From this preliminary study, it came out that our method is different to the two others because we took into account the loading time at the creep beginning. Besides we studied several loading programs and retained a five order non-linear polynomial which is the program that gave us satisfactory results. The other loading functions led to divergent results and wasn't present here as consequence. In the second part of this work, we devoted ourselves to the determination of non-linear parameters in the schapery's viscoelasticity equation, through a well developed and illustrated methodology. From this study, it is straight forward that non-linear parameters are stress dependent; confirming the results of several authors that preceded us in this studying field.