The continuous relaxation time spectrum can be extracted by fitting following model with n terms to either oscillation (G’(w), G”(w)) or Relaxation (G(t)) data.
For the numerical computation the spectrum H(lnt) is discretized (typical in the order of 100 steps). The spectrum represents all the pairs of fitted {Hi,ti} parameters and can be extracted into a new file if desired.
Use this model to extract the Continuous Relaxation time spectrum. The Relaxation time spectrum is used to interconvert linear viscoelastic material functions such as G’, G” to G(t); G’, G” to h(t) and y1(t); etc.
The calculation of the Relaxation Time Spectrum from experimental data is an ill-posed problem, in that small differences in the data can result in large differences in the spectra. Sophisticated mathematical techniques, such as the regularization technique, are used to counter this problem. Although the obtained spectrum has sometimes a peculiar shape, it is mathematically correct to use the spectrum for converting the viscoelastic functions.
