Burgers material

A Burgers material is a viscoelastic material which consists of a Maxwell material and a Kelvin material in series. It is named after the Dutch physicist Johannes Martinus Burgers.

Given four rheological constants a 1 , a 2 , a 3 , and a 4 , the Burgers model has the constitutive equation

where σ is the stress and γ is the rate of deformation.