3. Modeling A

3.1. Characteristics of modeling

A DIS_T element on a POI1 mesh is used to model the system.

The calculation is done on a modal basis. We block movements in \(Y\) and \(Z\), so the modal base only contains one mode.

We use the dynamic calculation functionality based on the modal basis of the operator DYNA_VIBRA, with the keyword CHOC to model local nonlinearity.

An obstacle of type PLAN_Z (two parallel planes separated by a game) is used to simulate the sliding plane. We choose to use NORM_OBST: \((0.,1.,0.)\) as the generator of this plan \(\mathit{Oy}\). The origin of the obstacle is ORIG_OBST: \((0.\mathrm{,0}\mathrm{.}\mathrm{,1}\mathrm{.})\), his game that gives the half-distance between planes is \(0.5\).

We place ourselves in the relative coordinate system (single-support loading) and we apply an accelerated loading with CALC_CHAR_SEISME.

A time step of \({3.10}^{\mathrm{-}5}s\) is used for time integration to limit the calculation time. This time step is much less than

.

The tangential friction stiffness is taken as high as possible to ensure the stability of the diagram, i.e. \({K}_{T}\mathrm{=}900000N\mathrm{/}m\). The value \({K}_{T}\mathrm{=}1000000N\mathrm{/}m\) leads to numerical instability.

The normal stiffness \({K}_{N}\) should be taken equal to \(20N\mathrm{/}m\) to exactly compensate for the weight of the mass. (the value of the game is \(\mathrm{0,50}m\)). Any other value leads to outlier results.

3.2. Characteristics of the mesh

Number of knots: 1

Number of meshes and types: 1 POI1