1. Reference problem#
1.1. Geometry#
We consider a system composed of a spring fixed at one end and provided with a point mass at the other end.

1.2. Material properties#
Spring stiffness: \(k\mathrm{=}10N\mathrm{/}m\)
Mass: \(m\mathrm{=}1\mathit{kg}\)
Wall stiffness: \(K\mathrm{=}50N\mathrm{/}m\)
1.3. Boundary conditions and loads#
The mass is attached to one end of the spring and the other end is fixed. It moves in the u direction and can impact against the wall which is \(e\mathrm{=}0.01m\) from its equilibrium position.
1.4. Initial conditions#
For nonlinear mode calculations, the behavior depends on the energy stored in the system.