Pm Patrick Teuffel

Towards smart building structures: adaptive structures in earthquake and wind loading control response – a review

This article is a review about applications for non-passive control response of buildings (namely active, hybrid and semi-active systems), wherein the degree of integration between control devices and structural system is explored. The purpose is to establish the current state-of-the-art in the development of ‘smart building structures’. A proper framework is proposed, therefore, for concepts such as ‘intelligent’, ‘smart’ and ‘adaptive’ while they make reference to a building which possesses an actively controlled response. Geometrical integration between control device and structural system is addressed as the key to allow further improvements in the achievement of truly ‘smart’ structures. Conclusions point out the fact that despite the advances done – especially in the field of structural control technology – there is no integration of devices within the host structures, and the reasons why further research must be developed in this direction.

Mechanical characterization of a shape morphing smart composite with embedded shape memory alloys in a shape memory polymer matrix

This article presents a smart composite that shows a reversible bending deformation from an initial flat configuration into a 90° angle controlled by local thermal activation. The novelty lies within the structural fixation of the deformation at room temperature without continuous energy input. The new structural architecture of antagonistic performing shape memory alloy actuators embedded in a shape memory polymer matrix is presented. The shape memory polymer is locally heated from the rigid glassy state to the easily deformable rubbery state by integrated heating wires. By subsequent activation of the different shape memory alloy actuators by resistive heating, the reversible performance can be realized. By deactivation of the heating wires in the shape memory polymer, the shape memory polymer fixates the deformation in its rigid condition. The actuation characteristics of the smart composite are investigated by thermo-mechanical experiments. The performance of the smart composite was investigated by thermo-mechanical experimentation of the individual components. The results show that a 90° bending deformation is feasible with the current material dimensions, but repeated deformation is restricted due to fatigue of the alloy. By superposition of the bending forces of the individual components, it is possible to estimate the bending angle of the composite material.

Adaptive structures and design concept of transformable joints

This article describes the research framework for adaptive structures and the design concept of transformable joints. The research of adaptive structures can be splitted into different scales: deformation mechanisms (whole structure), cooperation mechanisms (inter-component) and actuation mechanisms (intra-component). This research will focus on transformable joints, which are based on special material properties (actuation) to accomplish the change of joint stiffness between locked and released states (transformation). Thereby, the control of DOF can be achieved, in order to finally realise the whole structure’s form change (deformation). Alternatively under shock loads, the joints release and the structure occur certain deformation to dissipate energy and adjust to external loads. Afterwards, the structure recovers its original shape and removes residual strain through special/smart materials. Then the released joints relock again. By comparison of natural role models and adaptive structures, there are many similarities between them that we can learn from nature. In future research, e.g. adaptive stiffness, the experimental tests of potential materials and prototypes will be the main research methods. While for adaptive geometry, the knowledge of robotics, especially the part of geometric representations and transformations, will help to express this problem in mathematical way. This part will be mostly in conceptual level, so computer simulation will be used. The final goal of this research is to develop energy dissipation and shape-morphing strategies using transformable joints under varying loads as well as shock impact. These kinds of joints can not only be applied to tessellated shell structures, but also introduced to active facade systems.

Fully bio-based-composite footbridge : strain monitoring during use phase

Last year a bio based pedestrian bridge, first in its kind, has been installed at the TU/e University campus in Eindhoven. Material test formed the basis for the innovative design and the research project resulted in the production and installation of the bridge. Because there are still a lot of unknowns in the material behaviour of the used bio-composites, it was decided to monitor and test the bridge further after production. For this purpose optical FBG sensors have been installed. The FBG sensors show the material strains in good detail and the results of the thus measured strains in load tests are shown. The test results are compared with results from earlier material tests. The short term structural behaviour follows closely the used elastic models based on calculated as well as measured stiffnesses. The long term time dependent behaviour however shows a number of different influences from creep, temperature and moisture content that can not yet be fully explained by earlier measurements and tests.

Functional-layered textiles in architecture

In this chapter, new concepts are explored toward the development of multifunctional textile membranes, which are able to fulfill different architectural and aesthetic criteria, control the environmental conditions of the interior spaces or produce energy, while remaining lightweight. Through three case studies, the possibility of integrating new aspects into textile architecture, such as vegetation mats, aerogel granules insulation or algae cultures, to enhance the performance of the textiles is presented.

Adaptive Liquid Lens and Sunlight Redirection

The paper describes a novel system to alter and redirect sunlight under large roofs with the help of a liquid lens system. Focus lies on the computational design, testing, measurement and evaluation of the performance of a physical prototype. The results in terms of daylight and illumination of the interior, as well as the possibility for sunlight redirection, lead to an array of adaptive natural light spotlights, which are rather promising. The journal article is an extension of previously reported work[1].