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Understanding the nonlinear dynamical contact interactions within joints is crucial for understanding and predicting the dynamics of assembled structures. In spite of this, most experimental investigations focused on the global vibration behavior, since the local interactions at the interface cannot be observed with standard techniques. In the present work, an advance contact pressure measurement system is used in a unique way to analyze, in situ, the interfacial contact pressures and the contact area inside a bolted lap joint connecting two beams (Brake-Reuß beam). An important feature of the measurement system is that it is designed for frequency ranges including the typical vibration frequency of the Brake-Reuß beam's first eigenmode, and thus permits measurement under dynamic excitation. The dynamics of the contact pressures were investigated with different bolt torque levels and with different excitation levels. The experiments found that significant variations of the contact state occurred and that the contact pressure measurement system could adequately resolve this effect. The influence of the measurement system itself on the global vibration response of the Brake-Reuß beam was shown to be tolerable.

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The numerical simulation of sheet-layered lamination stacks is a challenging task in structural mechanics due to the layout of these components. Depending on the manufacturing process, these sheets are either linked together with the help of a bonding varnish or are just packed up and basically free to slip inside of the stack, which can result in a nonlinear deformation behavior. To avoid a full FE-simulation incorporating every layer, homogenization can be applied to identify a surrogate material model to achieve the desired accuracy by gaining performance. In this paper, a transversely isotropic material model is analytically formulated for a lamination stack with isotropic sheets in contact, which is captured with the help of a linear penalty method. The resulting stress-strain relation is compared to results obtained by a numerical homogenization.