FG Hybride Konstruktionen - Massivbau
To reduce wind-induced vibrations, Tuned Mass Dampers (TMD) are widely used in high-rise buildings. However, traditional TMD system requires large additional damping mass and huge installation space at the top floors of the building. In this paper, a novel distributed-Multiple Tuned Facade Damping (d-MTFD) system is investigated. This system employs the outer skin mass of the Double-Skin Facade (DSF) as the damping mass. In the upper stories, the DSF’s outer skin, mounted on a guide rail system, is designed to be parallel moveable. The passive/semi-active d-MTFD system, which is assumed to be installed on a 76-story benchmark building under across-wind excitation, is optimized using multi-objective Genetic Algorithms (GA) for two defined objectives: minimizing the peak top floor acceleration and controlling the maximum peak relative displacement of all the moveable DSF’s outer skins. On-off groundhook control and displacement-reducing bang-bang control are used as semi-active control strategies. The rolling friction caused by the guide rail system has a considerable impact on the optimization results. These results are presented in the form of Pareto fronts. Optimized parameters can be selected to yield a good trade-off between both objectives. The optimized passive/semi-active d-MTFD systems can highly improve the structural response. Compared with the optimized passive d-MTFD system, the use of semi-active control can reduce the vibration of the DSF’s outer skin significantly. Comparing the selected optimized cases with similar peak top floor acceleration, the peak top floor facade relative displacement using displacement-reducing bang-bang control decreases 58.3%, and the Root Mean Square (RMS) value decreases 61.4%.
This paper presents a sustainable semi-active distributed-Multiple Tuned Facade Damping (d-MTFD) system that utilizes the existing mass of the Double-Skin Facade's outer skin as damping mass to mitigate structural vibrations caused by wind excitation. Based on this concept, a prototype with one full-scale parallel moveable facade element has been developed, built, and validated. A stepper motor working together with its connected energy harvesting circuit is innovatively applied as an adjustable electrical damper and simultaneously as an energy harvester. Its feasibility has been proven through experiments using Hardware-in-the-Loop (HiL) simulations. An energy harvesting efficiency of 75% was achieved by using a two-stage power converter as the energy harvesting circuit. The self-sufficiency of the semi-active d-MTFD system was achieved.
Model-based active vibration control for next generation bridges using reduced finite element models
(2017)
Elastic kinetics are an approach to design transformable lightweight structures with a stable transformation process. The transformation is realized through elastic bending of structural members by exploiting the compliant material behavior. This lightweight and flexible design comes at the cost of increased sensitivity to static and dynamic disturbances. However, most of the current research focuses on the principles of elastic kinetic transformation instead of effective disturbance mitigation. This work focuses on dynamic disturbance mitigation for such transformable lightweight structures using active control. Modeling and controller synthesis are performed in the linear parameter-varying (LPV) framework, since the dynamics of elastic kinetic structures are transformation-state dependent due to geometric nonlinearities. Based on an LPV model in a grid-based representation, an LPV output-feedback control can be designed and synthesized via a gridding approach. This methodology is experimentally tested and validated for the example of an active hybrid roof structure prototype.
Linear Parameter-Varying Models for Convertible Structures in Civil and Structural Engineering
(2019)
This paper investigates the feasibility of the linear parameter-varying (LPV) framework for modelling the dynamic behaviour of ultra-lightweight convertible structures based on the elastic kinetic motion mechanism with a focus on civil and structural engineering applications. Model building is carried out for the example of a Fin Ray structure. In a first step local linear time-invariant (LTI) models are derived from a finite element model of the structure for different transformation states. On the basis of this collection of local LTI models, a grid-based LPV model is established. The derived LPV model is validated in simulation by comparison with data from a finite element model.