Viscoelastic Functions and Constants from the Spectra

CALCULATION OF VISCOELASTIC FUNCTIONS AND CONSTANTS FROM THE SPECTRA 

Equation 19 permits calculation of the relaxation modulus G t) when H is known. Similarly, the other moduli can be obtained by integrations which are equivalent to summing over all the elements of an infinite Maxwell model  

Each of these equations requires in principle knowledge of the spectrum over a wide range of time scale, depending on how fast the integrand converges. The kernel (that part of the integrand exclusive of H or L) approaches zero at low t 

An example of graphical integration of equations 19,23, and 24 for a favorable case of convergence, near the terminal zone of the spectrum H, is shown in Fig. 3-6. 

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