Textile buildings – innovation for the future

The EU funded research project contex-T has been continuing to develop lightweight, fire-safe, eco-friendly textile materials for buildings since its initiation in September 2006. This multi-disciplinary consortium is made up of 29 selected companies, institutes and universities from 10 EU countries.

With the Project entering the final phase of its 4 year programme many objectives of this wide-ranging research project on textile architecture have been successfully achieved.

Multifunctional inner and outer membranes
Promising results have been reached in optical properties for reflection of heat radiation. The surfaces have been modified by deposition of metals/metal oxides with PVD and CVD (Physical Vapour Deposition and Chemical Vapour Deposition). Surface treatment by fluorination, siliconisation and sol-gel formulations on membrane coatings have been developed to create easycleaning or even self-cleaning surfaces which would guarantee a life-span with an attractive optical impression of up to 60 years.

The bulk and surface properties of membrane materials for sound control, thermal insulation and moisture control could be enhanced by integrating aerogels. It is further applicable to intelligently combine different material types, in particular 2D/3D non-wovens or foamed materials for active thermal properties. Super absorbing materials are also integrated in the membrane composition to solve the condensation problem. The use of modifiedfunctionalised nano-particles and intumescent systems have proven very encouraging to dramatically improve the fire retardancy, but only if translucency is not required. Integration of thin solar cells and joining techniques like HF-welding and gluing into the new membrane materials were successfully optimised. In support of designing and combining many different features, artificial aging and large scale tests have been made and further tests of the functional properties are currently being studied.

Textile building: Konigsberg Jazz Festival
Source: Messe Frankfurt

Use of novel textile based components for textile architecture
A new composite combining a mineral matrix (phosphatic binder: Vubonite®) and Eglass fibres textile reinforcements has been developed. Two manufacturing processes are considered for industrial production: pultrusion and compression. The composite plates are bonded together and allow for the realization of different geometries of beam. The modification of flexural behaviour and particularly shear resistance are obtained by braiding technology. The optimization of the confinement depends on the different parameters (braiding angle, nature of fibres, volumic percentage, etc...) and the impregnation of external reinforcement by Vubonite® maintains the adhesion with the initial support.

As new cables using high modulus and high tenacity fibres and specific anchorage have been developed for textile architecture, they can be valorised for pre-stressing the confined hollow beams. The mechanical performance of sub-structural elements (beam and column) has been confirmed through experimental tests. Meanwhile, it is very important to note that failure is shown at a large deformation level due to specific cracking mechanism. The main interest of this new composite corresponds to a high level of fire safety associated to an innovative and effective construction process.

Modelling building physics and fire safety
To obtain good acoustical comfort in membrane based buildings, calculation models are written for single- and double layered membrane systems<, incorporating impervious membranes, permeable membranes and microperforated membranes. Permeable and especially micro-perforated membranes can be easily designed and tuned to have high sound absorbing properties in certain frequency regions. However, extra layers of poro-elastic (higher damping) or rigid elastic (higher mass) materials are necessary for good sound insulating systems.

Textile building: Winterbadeschiff, Berlin
Susanne Lorenz and AMP arquitectos, Gil Wilk Architekten and Thomas Freiwald, Berlin/Spain
Source: Messe Frankfurt

The evaluation of the thermal comfort in spaces covered with translucent membranes requires an accurate modelling of the radiant and convective heat transfer at the surfaces. A coupling strategy covering a building energy simulation program (EnergyPlus) and a CFD program (Fluent) has been studied and codes have been written to import the geometry from CAD tools and to generate input files for all programs.

EC fire safety regulations and performance-based fire safety engineering methods are taken into consideration to ensure the overall fire safety of the textile building. A LES (Large Eddy Simulation) type CFD code and a sub-model for hole opening in membranes have been validated against small-scale tests. Further validation of the modelling is planned by full-scale testing. Presimulations of the large-scale validation experiments have been conducted.

Testing and modelling structural behaviour and architectural aspects of tensile structures
There are four innovative elements in the new design for fiber cable terminations, which were validated through extensive fatigue and creep testing:

• the fibers are inserted on a male “conical” element, which is compressed and heated against a female casing causing radial pressure all around the cable, as it is tensioned. The special geometry of the “conical” and casing elements ensure uniform shearing along the entire cable length.
• Under compression, bonding of the fibers by an autogenous binding is succeeded by controlled melting of a small fraction of their periphery.
• The cable termination design has the ability of accommodating microsliding and flexing within a PET-arnite suitable busing, located at the termination entrance.
• The synergy in stiffness between the casing, the matrix produced by epitaxial crystallization of the melted fraction of the initial fibers, together with the fibers and the final conical element, result in an essentially improved fatigue strength and creep resistance.

Set-up of demonstration
Six different demonstrators have been developed to present some technologies and/or materials newly developed:

• Demonstrator 1 – a foldable structure for kinetic architecture, which is characterized by variable location, mobility, geometry or movement. It is to create spaces and objects that can physically reconfigure themselves to meet changing needs. The kinetic behaviour was investigated through construction of a ¼ scaled model made by plywood.
• Demonstrator 2 – it consists of a one story, one bay three-dimensional frame whose elements are made by Vubonite® reinforced by glass fibre fabrics. It is to investigate the possibility using this new material to build supporting structures with good fire resistance properties. The demonstrator was tested with satisfactory results.
• Demonstrators 3 & 4 – both demonstrators consist in thermo-boxes to evaluate membrane thermal properties but differ in their dimensions. It is possible to perform a quick preliminary assessment of the newly developed membrane materials through the small thermo-boxes and successively testing the selected materials through the large thermo-boxes. The materials will be mounted on the Demonstrators 5 and 6.
• Demonstrator s 5 & 6 - they are sufficiently large structures specifically thought to demonstrate membranes, cables, and belts. The supporting steel structure of one of the demonstrator has been realized while the other demonstrator is still in the design stage.

Knowledge management in Smart Innovation Networks
The effective management of knowledge – which is constantly acquired, developed and exchanged throughout the project – has been established in order to enable the deliberate sharing of knowledge as a valuable but intangible resource. To achieve this, several methods and technologies for knowledge management have been carefully selected and implemented.

From the beginning of the project, available knowledge has been analyzed and knowledge requirements of the different partners have been identified to derive a domain-specific knowledge structure. Together with models of knowledge and information flows between partners, this structure has been input for the design of a collaboration platform which enables partners to share their knowledge effectively. This platform allows, e.g. the exchange of documents and contact data, the presentation of new ideas and developments to, as well as the ordering of materials from other partners, or the coordination of the various tasks of the innovation activities.

In order to facilitate knowledge exchange and the coordination of innovation activities, smaller sub-groups (contex-T Innovation Networks) have been established focusing on the development of specific product features. The creation of these networks not only provides an efficient knowledge flow within the networks, but also supports an easy exchange of experiences across networks. Additionally, services regarding Life Cycle Assessment and Intellectual Property Rights are provided to support the networks.

Further Information:
Monique Thienpont
Project coordinator
Bexco NV
Tel.: +32 52 499367
Fax: +32 52 499380
eMail: mthienpont@bexco.be
web: www.contex-t.eu