# 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 ${\displaystyle a_{1}}$, ${\displaystyle a_{2}}$, ${\displaystyle a_{3}}$, and ${\displaystyle a_{4}}$, the Burgers model has the constitutive equation

${\displaystyle \sigma +a_{1}{\dot {\sigma }}+a_{2}{\ddot {\sigma }}=a_{3}\gamma +a_{4}{\dot {\gamma }}}$

where ${\displaystyle \sigma }$ is the stress and ${\displaystyle \gamma }$ is the rate of deformation.[1]