3.1.5.30. Viscoelastic Gap Material

This command is used to construct the uniaxial Jankowski Impact Material

uniaxialMaterial ViscoelasticGap  $matTag $K $c $gap

Argument	Type	Description
$matTag	integer	integer tag identifying material.
$K	float	stiffness.
$C	float	damping coefficient.
$gap	float	initial gap

This material is implemented as a compression-only gap material, so $gap should be input as a negative value. Due to the viscous component of this material, a small tensile force is present at the end of an impact event. .. Description:: This material model follows the constitutive law

\[f_c(t) = k(\delta(t)-g) + c \dot{\delta} (t)\]

where t is time, \(f_c (t)\) is the contact force, \(k\) is the stiffness ($K), \(\delta(t)\) is the indentation, g is the initial gap ($gap), c is the damping coefficient ($C) and \(\dot{\delta}(t)\) is the indentation velocity.

Code Developed by: Patrick J. Hughes, UC San Diego