3. Modeling A

3.1. Characteristics of modeling

The geometric and material properties of the model are those presented above. The pipe is modelled using Timoshenko straight beam elements: POU_D_T. It is broken down into 60 elements spread over six sections.

Nodes \(A\) and \(C\) are stuck in the directions \(x\), \(y\), and \(z\) in translation and rotation.

The amortization of the fluid structure at rest is 0.499%.

3.2. Characteristics of the mesh

The total number of nodes used for this mesh is 61.

The meshes are 60 in number and of type SEG2.

The mesh file is written in ASTER format.

3.3. Calculation steps

The flow speed profile and the parameters taking into account fluid-structure coupling are defined using operators DEFI_FONC_FLUI and DEFI_FLUI_STRU. The modal parameters of the structure are calculated taking into account fluid-elastic forces using the operator CALC_FLUI_STRU. The definition of random excitation is carried out using the operator DEFI_SPEC_TURB. Excitation is projected on a modal basis using the PROJ_SPEC_BASE operator. The modal response intervals are calculated using the DYNA_SPEC_MODAL operator. The auto-spectra of movement at the nodes are deduced by using the operator REST_SPEC_PHYS.