Prony series

Summary

A Prony series is a finite sum of decaying exponentials plus a constant, used to represent the relaxation modulus of a linear viscoelastic material. It is exactly the relaxation modulus of a generalized Maxwell model, so each term has a mechanical meaning as a spring–dashpot arm. Measured relaxation curves are fitted by Prony series, and finite element codes use them because the hereditary integral can then be updated step by step.