Generalized Kelvin Chain Model – Total Strain

J (t) = \frac{ε (t)}{σ} = \frac{1}{E_{0}} + \sum_{k = 1}^{n} \frac{1}{E_{k}} (1 - e^{- \frac{t}{τ_{k}}}) + \frac{t}{η_{∞}}

ε	Strain
t	Time
σ	Stress
E0	Modulus of elasticity of the free spring (immediate strain)
k	Current element
n	Number of elements
Ek	Modulus of elasticity of the current element
e	Euler's number
τk=ηk/Ek	Delay time of the current element
η∞	Dynamic viscosity of the free damper (Newtonian fluid)

;