13. Real-Time Hybrid Simulation Study of a Physical Duffing Absorber Attached to a Virtual Nonlinear Structure

In structural dynamics, real-time hybrid simulation is used for physical testing of critical components. When compared to traditional testing methods, the approach is very efficient and reliable, if important surrounding effects can be included in a virtual model (simulation model) which is interacting with the physical component (physical model). The virtual model must be processed in real time, and proper coupling is essential for reliable and consistent test results. Consequently, the physical interface conditions must be satisfied, and therefore, a transfer system is generally required for component testing. In the work presented, a real-time hybrid simulation experiment is used to study the influence of a Duffing absorber on the dynamics of the fundamental mode of vibration of a nonlinear host structure. Only standard hardware components are used, e.g., electrodynamic shaker, force, displacement and acceleration sensors, as well as a real-time processing unit. The study is currently limited to periodic forcing, and consequently, only the steady-state response is studied. Since the physical absorber investigated behaves nonlinear elastic, all measurements can be collected sequentially to generate high-precision force response diagrams for different amplitudes and frequencies. So far, the experimental results agree well with theoretical predictions and confirm that nonlinear dynamic absorbers are particularly suited to mitigate vibrations of nonlinear host structures. As the properties of the nonlinear absorber are adjustable, existing design rules can be verified by the proposed experimental setup.