On the Analytical Determination of Relaxation Modulus of Viscoelastic Materials by Prony's Interpolation Method

A computer implementation to Prony's curve fitting by exponential functions is presented. The method, although more than one hundred years old, has not been utilized to its fullest capabilities due to the restriction that the time range must be given in equal increments in order to obtain the best curve fit for a given set of data. The procedure used in this paper utilizes the 3-dimensional capabilities of the Interactive Graphics Design System (I.G.D.S.) in order to obtain the equal time increments. The resultant information is then input into a computer program that solves directly for the exponential constants that yield the best curve fit. Once the exponential constants are known, a simple least squares solution can be applied to obtain the final form of the equation.