LINEARIZED JOINT DAMPING MODEL FOR ASSEMBLED STRUCTURES WITH INHOMOGENEOUS CONTACT PRESSURE USING THIN-LAYER ELEMENTS

Damping properties of assembled structures are largely influenced by joint damping at mechanical interfaces. Therefore, numerical models must depict these dissipative effects in order to attain sufficient accuracy for vibration responses when structural dynamic simulations are carried out. Finite element models with so-called thin-layer elements (TLEs) can be efficiently applied to model joint damping. Thereby, TLEs with a linear orthotropic material model are placed on all mechanical interfaces. Stiffness and damping parameters for these elements are experimentally determined on a generic lap joint. In this approach, all TLEs contain identical damping and stiffness parameters. However, normal and tangential loads in assembled structures typically vary over the interface area. As joint damping depends, among other factors, on normal and tangential loads, a uniform parametrization of the TLEs cannot depict these conditions accurately, limiting the applicability of the original approach. In this paper an improved finite element modeling approach for structures with inhomogeneous contact pressure distributions using thin-layer elements is presented. Based on experimental data, an empirical model is derived to allow improved joint damping prediction under consideration of applied normal and tangential loads. This facilitates a load-dependent parametrization of each individual thin-layer element, resulting in a finer linearization of the nonlinear joint behavior. This method is applied to a test structure and compared to the original approach. All simulations are verified experimentally.