VibroDamp - Optimal Vibration Reduction for Lightweight Structures with Particle Damping Using Frequency Based Substructuring Objectives
The reduction of vibrations or noise plays an important role for the design of many applications. Especially lightweight structures are prone to strong vibrations disturbances. Particle damping was found to be an efficient way to reduce vibrations of lightweight structures since not much weight has to be added.
Figure 1 Dissipation mechanisms of particle damping
However, the modelling of particle damping is still difficult due to nonlinear contact and friction effects on particle level as well as its amplitude dependence. For proposed modelling so far, either the validity is only given for a restricted range of operating conditions, the computational time is very high (e.g. discrete element method) or an extensive amount of experimental work for dynamic characterization at the final product stage must be done. Using these predictive models design optimizations for engineering decision making are not feasible. Here, instead, the use of a Frequency Based Substructuring and combined optimization approach is presented as a simple and fast design technique.
Method
The Frequency Based Substructuring (FBS) is a frequency domain method to solve linear vibration problems by decomposing a structure into several smaller parts, the so-called substructures. Each substructure can individually be characterized by its frequency response functions (FRF), that can be determined via simulation or experimental testing. This so-called experimental substructuring is one of the major advantages of this approach if experiments are carried out appropriately. Thus, real (non-linear, frequency dependent) physical effects, that cannot be modelled in an appropriate manner, can be incorporated into a frequency based assembled system response. So one can derive the transfer function matrix Y(ω) of the coupled system
with the boolean matrices B for Interface compatibility and L for the equilibrium of connection forces as well the unit load f.
Application
Interior Components for the Aircraft Cabin are subjected to a dynamic loads in terms of safety as well as comfort for passengers. The carcasse of the interior components are made of honeycomb sandwich panels. For the application of particle damping the honeycomb core can serve as particle container. Additionally hollow inserts or attachments pose a similar opportunity to apply particle damping. The goal of this research is to find an approach to efficiently optimize the application of particle damping to reduce the vibration amplification at resonance.
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