1. But

Calculate added mass [R4.07.03], damping, or stiffness matrices.

The matrices are induced by a perfect, incompressible fluid, at rest or in potential flow, on a 2D, 2D axisymmetric or 3D structure.

The terms of these matrices are calculated on the modal basis of the structure in a vacuum.

The calculation of the terms of the matrices is carried out by solving the equations of LAPLACE in the context of a thermal analogy. The calculated temperature plays the role of pressure in the fluid domain. It is therefore necessary to take care to define the fluid material by thermal characteristics, and assign a thermal model to the part of the mesh that represents the fluid.

Thanks to this operator, it is possible to determine, for example, the matrices added to a bundle of tubes, considered as a single structure immersed in the same fluid.

As part of a calculation by dynamic substructuring, it is also possible to evaluate the mass matrix added on a generalized model.

For systematic uses of this command and to simplify the writing of the command file, we will effectively use the macro command MACRO_MATR_AJOU [U4.66.11].

Produces a data structure of type Matr_asse_gene_r.

The following test cases show examples of how to use this operator:

• • • • FDLV100 [V8.01.100],

      • FDLV101 [V8.01.101],

      • FDLV102 [V8.01.102],

      • FDLV103 [V8.01.103],

      • FDLV104 [V8.01.104],

      • FDLV105 [V8.01.105],

      • FDLV106 [V8.01.106],

      • FDLV107 [V8.01.107],

      • FDLV109 [V8.01.109],

      • FDLV110 [V8.01.110].