VACUUMATICS; Systematic Flexural Rigidity Analysis

The structural integrity of vacuumatics relies on the principle of prestressing unbound particles inside an enclosed membrane. By introducing a negative pressure (partial vacuum) inside this airtight flexible enclosure, the membrane is tightly wrapped around the outer particles, hence effectively bonding the particle filling to create (adaptable) load-bearing structures. Analytical and numerical studies on the fundamental prestress derivation of vacuumatically prestressed structures have shown that the effective prestressing forces between the particles largely depend, apart from the differential in (air) pressure differential, on the elastic properties of the skin material. The flexural rigidity of vacuumatics is mainly determined by the material properties of the particles and membrane used. Variations in elasticity of the skin and particle filling, and with this the shape, size, compressiveness, roughness, and packing density of the individual particles, highly influence the structural behaviour of vacuumatic structures. In order to explore the influence of different particle and skin characteristics (or parameters) on the flexural rigidity, experimental research has been carried out by means of four point bending tests. Different types of particles were used to discover behavioural trends dependent on the parameters varied. The results of this study provide an enhanced understanding of the true overall structural response of vacuumatics. By systematically elaborating the different parameters, we are able to determine what specific material properties are desired to design the ‘most efficient’ vacuumatic structure for every application

Foliebekisting maakt dubbelgekromde betonconstructies betaalbaar

Dubbel gekromde betonconstructies in civiele werken zien we steeds vaker in Nederland. Technisch zijn dergelijke constructies goed te maken, maar hoe houden we het betaalbaar? De bekisting en de stalen wapening zijn de duurste onderdelen van het productieproces. Om die kosten te drukken, doet constructie adviesbureau ABT onderzoek naar een nieuw type bekisting. Die bestaat uit folie

Vrije vormen met vacuüminfusie-beton

De vraag naar vrijevormarchitectuur of free-form architecture, blijft vanuit de markt toenemen, evenals de toepassing van steeds lichtere draagconstructies en multifunctionele bouwdelen. Het ideale bouwmateriaal dat nodig is om deze architectonische trends (letterlijk) vorm te geven, zal dus nagenoeg elke gewenste vorm moeten kunnen aannemen. Hierbij moet het tevens beschikken over voldoende draagkracht, stijfheid en isolerend vermogen tegen diverse externe factoren zoals wind, temperatuur en geluid. Wellicht bestaat dit ideologische materiaal echter al: beton

Vacuumatics: 3D formwork systems : Investigations of the structural and morphological nature of vacuumatic structures so as to be used as semi-rigid formwork systems for producing 'free forms' and customised surface textures in concrete for architectural applications

One of the most important architectural trends of the last two decades is commonly referred to as ‘digital architecture’. This trend comprises digitally-generated geometrically complex, often irregular, yet fluent double-curved shapes (or rather ‘free forms’) in architecture. Although advanced digital manufacturing systems are emerging in architecture, the construction processes in general require some sort of boost to ‘keep up’ with the already heavily advanced (digital) design and analysis processes. Curable materials (such as concrete) are considered particularly useful for the realisation of the desired ‘free forms’. The formability and the adaptability of the formwork system of choice, however, are typically considered the limiting factors. Previous research by the author has indicated the potential of so-called vacuumatic structures (or simply ‘vacuumatics’) to be used as semi-rigid formwork systems. Little is known, however, about the specific structural properties and to a lesser extent the morphological formability of these types of structures. Vacuumatic structures typically consist of an (unbound) aggregate core, which is enclosed by a flexible membrane envelope and structurally stabilised by means of an internal underpressure. The research presented in this thesis aims at defining the influence of the individual characteristics of the aggregate core and the membrane envelope on the overall flexural behaviour of vacuumatic structures. Furthermore, the basic structural mechanics is explored with which the flexural behaviour of vacuumatic structures can be explained. Apart from that, this research aims at defining which shaping techniques are considered most effective for using vacuumatic structures as semi-rigid formwork systems for producing ‘free forms’ and customised surface textures in concrete for architectural applications

Vacuumatics 3D Formwork Systems: customised concrete architecture

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Vacuüm als constructief bindmiddel

‘Ongebonden’ granulaat kan nagenoeg elke geometrische vorm beschrijven. Dit biedt perspectief voor de maakbaarheid van ‘vrije vormen’ in de huidige architectuur. Door dit granulaat in een flexibele, luchtdichte omhulling te brengen en het pakket vacuüm te zuigen ontstaat een constructieve binding (of beter gezegd voorspanning), waardoor krachten door het granulaat kunnen worden overgedragen

Foliebekisting heft alle beperkingen op = Foil formwork eliminates all restrictions

Betonbekisting kwam als een van de mogelijke toepassingen naar voren uit zijn afstudeeronderzoek aan de Technische Universiteit te Eindhoven (TU/e) naar de mogelijkheden van Vacuumatics. Een inspirerende conclusie voor Frank Huijben die zijn studie voortzette in een promotieonderzoek. "Beton is een prachtig materiaal. Omdat het verse betonmengsel vloeibaar begint, zijn de mogelijkheden in vorm vrijwel onbeperkt. De bekisting bepaalt nu de grenzen." Concrete formwork as one of the possible applications of Vacuumatics – that is one of the findings presented in his thesis submitted for graduation from the Technical University of Eindhoven (TU/e). An inspiring conclusion for author Frank Huijben, who continued his study in his Ph.D. research. "Concrete is a wonderful material. Because fresh concrete starts out as a liquid mix, its applications are virtually limitless. Currently, the limits are set by the formwork.

3D vormen in beton : onderzoek naar Vacuumatics 3D-bekistingsystemen

De haalbaarheid van geometrisch complexe vormen in beton, aan de orde bij ‘blobarchitectuur’ en ‘free-form design’ wordt vooral bepaald door de flexibiliteit en aanpasbaarheid van het toegepaste bekistingsysteem. Aan de Technische Universiteit Eindhoven (TU/e) wordt onderzoek gedaan naar in vorm aanpasbare, onder invloed van vacuüm voorgespannen driedimensionale bekistingsystemen, ofwel Vacuumatics 3D-Bekistingsystemen. De constructieve werking van Vacuumatics berust op het principe dat losse vulelementen in een gesloten flexibele omhulling alzijdig worden voorgespannen tot een samenwerkend geheel in een voorgedefinieerde vorm

Vacuumatics: vacuumatically prestressed (adaptable) structures

Vacuumatics rely on a relatively "new" and therefore yet unproven structural principle of prestressing incoherent (structural) elements by means of atmospheric pressure, by creating a (partial) vacuum inside an enclosing skin (figure 1). This technique leads to rigid – but reconfigurable – load bearing structures (figure 2), quite analogue to vacuum packed coffee. In an attempt to explore the structural potential of vacuumatically prestressed structures the force distribution throughout a simplistic 2-dimensional representation of such a structure is approached by means of an analytical model. A comparable numerical approach of the technique illustrates a remarkable resemblance in prestress derivation, differentiating a so called "direct" and an "indirect" prestressing component, indicating the significance of the elasticity of the applied skin material. This paper sets out to describe the ongoing study on the structural – as well as geometrical – behaviour of vacuumatics, aiming for a fundamental understanding in and control over the underlying design principles