A substructuring approach based on mechanical admittances to solve vibro-acoustic problems in the mid-frequency range

In the low frequency range, discretization methods such as the Finite Element Method are the preferred techniques to solve vibro-acoustic problems. The main limitation of such approaches is that the mesh needs to be refined when the frequency increases, leading to prohibitive calculation costs. This paper presents the Condensed Transfer Function (CTF) method for substructuring vibro-acoustic problems. The problem is split in several structural, acoustic or vibro-acoustic subsystems that are studied individually before being assembled. The vibro-acoustic behavior at the boundaries of the subsystems is expressed in terms of mechanical admittance for structures and acoustic impedance for fluid domains. A set of condensation functions is used as a basis to express the values at the boundaries. The coupling between subsystems is written through the continuity equations of mechanics. Compared to classical reduction methods such as Craig-Bampton, this approach does not require the prior knowledge of the modal basis of the subsystems. Also, the CTF method allows coupling subsystems that are described by different techniques, i.e., analytically, numerically or experimentally. The principle of the method will be recalled and example of applications will be given. In particular, numerical and experimental results on a stiffened cylindrical shell will be compared.In the low frequency range, discretization methods such as the Finite Element Method are the preferred techniques to solve vibro-acoustic problems. The main limitation of such approaches is that the mesh needs to be refined when the frequency increases, leading to prohibitive calculation costs. This paper presents the Condensed Transfer Function (CTF) method for substructuring vibro-acoustic problems. The problem is split in several structural, acoustic or vibro-acoustic subsystems that are studied individually before being assembled. The vibro-acoustic behavior at the boundaries of the subsystems is expressed in terms of mechanical admittance for structures and acoustic impedance for fluid domains. A set of condensation functions is used as a basis to express the values at the boundaries. The coupling between subsystems is written through the continuity equations of mechanics. Compared to classical reduction methods such as Craig-Bampton, this approach does not require the prior knowledge of the modal ba...