The extended finite element method combined with a modal synthesis approach for vibro-acoustic problems

Antoine Legay (1)

1 LMSSC - Laboratoire de Mécanique des Structures et des Systèmes Couplés

The optimization of a vibro-acoustic problem is of main importance for passengers' comfort in transportation vehicles in terms of interior noise. Engineers use numerical tools to predict the response of this coupled problem, but it may lead to a prohibitive computational time. Based on FEM, this work aims at reducing the computational time. The first idea is to keep the same mesh of the acoustic cavity for all the structure configurations and to enrich the pressure approximation by using the extended FEM (XFEM). The enrichment is based on a Heaviside function completed at the structure tip by a continuous ramp function. The second idea is to build reduced basis. The structure basis is composed of its eigenmodes, whereas a modal synthesis method with a fixed interface is used to build the fluid basis. The interface DOFs are the enriched DOF of the XFEM, whereas the internal domain corresponds to the acoustic cavity with no structure. These two combined ideas enable to minimize the computational time in the study of the influence of the structure positions in an acoustic cavity. The method is implemented for shell structures embedded in a 3D acoustic domain.

Mots clés: XFEM; modal synthesis method; reduced order model; vibro-acoustics

Domaines: Mécanique [physics.med-ph]; Vibrations [physics.class-ph]; Acoustique [physics.class-ph]

Antoine Legay. The extended finite element method combined with a modal synthesis approach for vibro-acoustic problems. International Journal for Numerical Methods in Engineering, 2014, 101, pp.329 - 350. ⟨10.1002/nme.4798⟩. ⟨hal-01422329⟩