3. Modeling A

3.1. Characteristics of modeling

Figure 3.1-a: Modeling of the anti-seismic device

The jaws that insert the device are each modeled by a discrete element with 3 degrees of freedom DIS_T.

The anti-seismic device is simulated using the keyword factor ANTI_SISM of the operator DYNA_VIBRA.

Node \(\mathrm{NO1}\) is subject to enforced acceleration \({\gamma }_{1}(t)\), node \(\mathrm{NO11}\) to \({\gamma }_{2}(t)=0\). We calculate the relative displacement of node \(\mathrm{NO2}\) and its absolute displacement.

The time integration is carried out with the Euler algorithm and a time step of \(\mathrm{1,25}\mathrm{.}{10}^{-5}\) seconds. The calculations are archived every 80 steps.

We consider reduced damping \({\xi }_{i}\) to zero for all of the two calculated modes.

3.2. Characteristics of the mesh

The mesh consists of 4 knots and 4 DIS_T meshes.

3.3. Tested sizes and results

The absolute displacement of the node \(\mathrm{NO2}\): NO2_DX_A and the force in the anti-seismic device are calculated. The values are compared to those calculated by a MATLAB function.

	Reference
Maximum effort (N)	1,266E+04
Effort — RMS	7,912E+03
NO2_DX_A max (m)	1.670E—02
NO2_DX_A — RMS	1,180E—02
NO2_DX_R max (m)	1.266E—06
NO2_DX_R — RMS	7,798E—07

We trace the evolution of the force that is exerted in the device as a function of the absolute displacement of the node \(\mathit{NO2}\). Comparisons are made to the measured quantities.

Taking into account the approximation of the excitation imposed on the vibrating table in one sine, the model implanted in*Code_Aster* is representative of the device tested.

The temporal evolution of the movement of the device is also traced:

Time (s)