Creep and the Retardation Spectra Generalized Kelvin-Voigt Model

3 Creep and the Retardation Spectra Generalized Kelvin-Voigt Model 

Let us consider a simple uniaxial creep response. If a creep stress a is given by 

In the same way as we did for stress relaxation, we combine the instantaneous elastic, viscous and pure stress-relaxation properties, and write the response as 

Substituting (2.264) into (2.262) and changing the order of integration, we have 

The response of a simple one-unit Kelvin-Voigt model shown by Fig. 2.14b can be written in a form similar to (2.269) as 

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