Matthias Bosch

Zusammenfassung

Um bei der Auslegung adaptiver Stahlbetonplatten mit integrierten fluidischen Aktoren den Lastfall „Aktuierung“ zu berücksichtigen, bedarf es zusätzlicher Kriterien für die Aktorplatzierung. Für die Diskussion derartiger Kriterien werden Finite Elemente Simulationen unter Verwendung eines bruchmechanischen Schädigungs-Plastizitätsmodell an einem Fallbeispiel durchgeführt und dem aufgebrachten Aktordruck gegenübergestellt.

Zusammenfassung

A high proportion of the CO2 emissions worldwide are caused by the construction sector or are associated with buildings. Every part of the industry needs to reduce its share of emissions, so the building sector must also do its part. One possible solution for achieving this reduction in the field of load-bearing structures is the use of adaptive structures. This research focuses on adaptive slab structures, which require specific actuators to be integrated into the system. Conventional actuators are not suitable due to the prevailing requirements, namely installation space and performance. For this investigation, the actuator is divided into different functional components. A rough description of the requirements for one component, namely the energy converter, is given. Different concepts are developed, tested, and compared with numerical results. Due to the requirements, the concepts are limited to hydraulics. The authors then present a comparison of different simulation strategies for the energy converter. Overall, this paper provides a new contribution to the design of energy converter concepts for integrated hydraulic actuators in slabs, along with experimental verification of the working principle of the energy converters to meet the requirements. A simplified numerical model is proposed to estimate the behavior of the energy converter during the early design phase.

Zusammenfassung

One possible approach for saving structural mass and related emissions is to design adaptive load-bearing structures, i.e. actively reducing deformations under changing loads through actuation. This paper describes the application of a methodology based on influence matrices to identify a feasible actuator size for actuator placement in reinforced concrete slabs under multiple load cases. The design is implemented in a physical prototype comprising a concrete slab with a clear span of 2 m x 2 m, being equipped with fluidic actuators that are controlled via a cascade controller. Experimental tests show that the displacement response of the adaptive slab under twice the design load can be kept equal to that of the passive slab under the design load. Thus, proof of concept is provided that considerable material savings can be achieved by employing integrated fluidic actuators in two-way slabs.

Zusammenfassung

Adaptive structures have the potential to play a significant role in saving resources in the construction industry in the future. For realisation, this requires actuators that meet the requirements of different buildings with their specific load-bearing structures. In the past, the actuators were mainly developed particularly for one exemplary load-bearing structure. This paper analyses the primary classifications for buildings, followed by challenges of adaptive structures, before outlining the draft of a framework for actuators for adaptive structures to speed up and simplify development.

Zusammenfassung

The construction industry is responsible for much of the global resource depletion and greenhouse gas emissions. New methods are needed to significantly reduce resources and emissions associated with load-bearing structural elements. Conventional floor slabs embody up to 50% of the total structural mass in buildings to satisfy deflection limits and provide the required bending stiffness. Significant mass savings can be achieved by reducing actively the deflection response against loading using sensors and actuators. Fluidic actuators have been therefore developed to be embedded in the compression region of reinforced concrete slabs under bending action. Through the controlled expansion of such fluidic actuators, deflections and stresses caused by vertical loads are reduced within the required limits. This paper offers a benchmark study evaluating the effect of actuator placement and actuation forces for two different objectives: reduction of displacements and reduction of bending moments. A method to fulfil both objectives simultaneously has also been investigated. Depending on the direction of the actuation forces caused by pressurized regions within the cross-section of the slab, there are two main actuation modes: uniaxial and biaxial. Results show that the efficacy of uni- and biaxial actuation modes depend on the control objective. To compensate for displacements and moments simultaneously, biaxial actuation is most effective and requires the lowest actuation forces.

Zusammenfassung

The building sector is responsible for a high CO2 footprint each year. To reduce the required resources and increase the load-bearing capacity of structural elements, designing structural elements adaptive seems to be an appropriate solution. In particular, for structural integration in adaptive slabs, conventional actuators are not suitable due to the requirements in terms of installation space and performance. Therefore, different concepts on fluidic pressure chambers for adaptive slabs are developed, tested, and compared with numerical results. The outcome of this investigation is presented in this contribution and can be used for the further development of fluidic actuators for adaptive slabs.