Martin Trautz

Flexible Manufacturing of Double-Curved Sheet Metal Panels for the Realization of Self-Supporting Freeform Structures

Product development is complex due to the manifold requirements resulting from various perspectives, such as design, production, safety and sales. A concurrent engineering (CE) approach permits to respect all perspectives in the early development stage. However, in the architecture and construction sector for example, CE is particularly difficult to realize, because the central steering for this collaboration process is missing. Thus, the application of CE in the research sector can promote technical progress and cost reduction. In the specific field of freeform architecture, in most cases an individual shape of single components is unavoidable and the use of standard components impossible. Due to missing universal and mature construction concepts for freeform buildings, they are mostly realized with customized solutions often including material-consuming substructures, while the visible skin has only limited structural and functional properties.In this context the present paper proposes a novel universal panel system made of double-curved sheet metal layers enabling the assembly of self-supporting lightweight structures for the realization of freeform surfaces. The panel system has been developed in cooperation of architects, construction and production engineers, successfully applying an interdisciplinary CE approach. As a result, the concept allows for material and cost efficient solutions applicable for a wide range of freeform applications. The detailed development of the panel system is still in progress.Besides the general panel concept, the paper presents in particular the corresponding manufacturing chain and the tooling concept. Accounting for the varying part geometries in this application a flexible manufacturing chain based on the combination of stretch forming and incremental sheet forming has been developed. The entire production process is implemented in a single machine setup and successfully tested on a small-scale prototype.

Analysis into Differences between the Buckling in Single-Point and Two-Point Incremental Sheet Forming of Components for Self-Supporting Sheet Metal Structures

In the architecture and construction sector the trend for individualization is often expressed in complex-shaped freeform buildings. Due to missing universal and mature construction methods for freeform buildings, they are usually realized with customized solutions that often include massive, material-consuming substructures, while the visible skin has neither structural nor functional properties. In this context a new concept for self-supporting lightweight structures for the realization of free-form surfaces and the production of the corresponding components has recently been proposed. Taking into account the large part dimensions and the varying part geometries in this application a flexible production chain based on incremental sheet forming has been developed and optimized. It has been validated by producing six-sided large-scale pyramids in 140 similar variants which were assembled to a self-supporting free-form demonstrator. Two-point incremental sheet forming (TPIF) was used with a universal partial supporting tool with the goal to produce all variants without dedicated tooling. Although the majority of pyramids was produced successfully with the applied TPIF strategy, there was a small number of parts with a very asymmetric shape that showed severe buckling in the side walls. For a detailed analysis of this observation the asymmetry was quantified using a wall angle ratio. Subsequently, a single-point incremental sheet forming (SPIF) strategy was successfully applied as an approach to avoid buckling. The results confirm the assumption that the circumferential expansion in SPIF suppresses buckling due to tensile stresses in the side walls, whereas the circumferential compression in TPIF triggers buckling due to the compressive stresses in the side walls.

Determination of the Stress Distribution in Timber Elements Reinforced with Self-Tapping Screws Using an Optical Metrology System

The use of self-tapping screws with continuous threads to reinforce and join timbers in addition to glulam elements represents an effective, simple and economic method. The high withdrawal resistance of the screws as well as its continuous bond with the wood enables an effect similar to steel reinforcement in concrete structures. Within the framework of a research project, funded by the German Research Foundation (DFG) at the Chair of Structures and Structural Design in cooperation with the Institute for Building Material Research of the RWTH Aachen University, several tests have realized to investigate the bond behaviour, the force transfer and the anchorage length of the screws. Herewith the stress distribution will be determined with an optical 3D field measuring system, based on the digital image correlation (DIC) method, which measures the strain by observing the surface of the test specimens. To ensure the accuracy of the measurements for a wide measuring field of wood surface, a comparison study was conducted involving traditional electrical sensors (i.e. strain gauges and LVDTs). The results of this study, which confirm the accuracy regarding the determination of stress distribution for small deformations on the wood surface with optical 3D field measuring system, will be presented in this article.

Life cycle assessment and sustainable engineering in the context of near net shape grown components: striving towards a sustainable way of future production

Technical product harvesting (TEPHA) is a newly developing interdisciplinary approach in which bio-based production is investigated from a technical and ecological perspective. Society‘s demand for ecologically produced and sustainably operable goods is a key driver for the substitution of conventional materials like metals or plastics through bio-based alternatives. Technical product harvesting of near net shape grown components describes the use of suitable biomass for the production of technical products through influencing the natural shape of plants during their growth period. The use of natural materials may show positive effects on the amount of non-renewable resource consumption. This also increases the product recyclability at the end of its life cycle. Furthermore, through the near net shape growth of biomass, production steps can be reduced. As a consequence such approaches may save energy and the needed resources like crude oil, coal or gas. The derived near net shape grown components are not only considered beneficial from an environmental point of view. They can also have mechanical advantages through an intrinsic topology optimization in contrast to common natural materials, which are influenced in their shape after harvesting. In order to prove these benefits a comprehensive, interdisciplinary scientific strategy is needed. Here, both mechanical investigations and life cycle assessment as a method of environmental evaluation are used.

Interdisciplinary Factory Planning in the Education of Mechanical Engineers and Architects

The current and future challenges in the field of factory planning result from social, political and economical developments and exceed solely technical advances of production engineering. An interdisciplinary approach that achieves results in the fields of social sciences as well as engineering is inevitable to respond to future challenges in factory planning. Only by merging the special knowledge of different disciplines, the field of factory planning will be prepared for future needs. In order to pursue this interdisciplinary approach, a multidisciplinary research group was founded at RWTH Aachen University. The Chair of Production Management (Faculty of Mechanical Engineering) and the Chair of Structures and Structural Design (Faculty of Architecture) at the RWTH Aachen University are part of this research group. Besides research activities, one goal of the research group is to encourage an interdisciplinary education in the field of factory planning in which production technology and building technology are integrated. Up to now, the cooperation in teaching was implemented in three projects in the topics of Automotive Industry, Solar Energy and Machine Tools offered for master students at the faculty of architecture. In the course of these projects, teachers of both chairs gave lessons and guided students of architecture in the process of planning industrial buildings. The interdisciplinary formation of teachers and students fosters learning from each other’s expert knowledge and prepares students for future tasks in interdisciplinary planning teams. The abilities to work in a team and to find solutions in a creative dialogue are encouraged in real or fictional projects. The different levels of knowledge of the students and the various methods in the field of factory planning pose particular challenges. The essential knowledge is imparted by a collective lecture to facilitate the communication between the disciplines. At the end of the course, each project is the result of different disciplines whose exigencies have been synchronized.

Mechanism Theory in Architecture Education

In mechanical engineering tasks concerning motion and moving parts are very common, thus of course topics like kinematics and mechanism theory are content of teaching in various lectures, exercises and laboratories. At RWTH Aachen University besides mandatory basic courses for all engineering students, continuative courses for students specialized on engineering design or automotive engineering impart profound knowledge. In architecture education the focus lies on the design of buildings in consideration of social, functional, esthetical and statical aspects. Although due to the demand of sustainable and adapting buildings the importance of deployable structures and kinematic parts is increasing, these topics are rarely found in education. Suitable opportunities to bring interested prospective architects in touch with mechanism theory are design projects scheduled for master students. Following an existing cooperation in the research field of foldable structures the Chair of Structures and Structural Design (Faculty of Architecture) and the Department of Mechanism Theory and Dynamics of Machines (Faculty of Mechanical Engineering) offered in the winter semester 2012/13 an interdisciplinary task of designing a foldable bridge to a group of architecture students. The focus of this student project was on the design of a new foldable bridge, but in order to enable the students to solve this unusual task some preliminary activities were performed. The project started with analyses and presentations of existing solutions followed by lectures and workshops providing contents from architecture, arts and mechanism theory. Observations of the project showed that thanks to this preparation students considered kinematic issues as well as architectural ones from the very beginning. The aim of this paper is to present how mechanism theory can be integrated into Interdisciplinary education, which content the authors consider being important for students and which influence can be observed in students’ results.

Faltung und Origami - Prinzipien für Konstruktionen in Architektur und Ingenieurwesen

Prinzip des Faltens ist allgegenwärtig und findet sich in Natur, Alltag, Design sowie in der Technik in einem großen Variantenreichtum. In der Natur wird es sowohl als optimiertes Leichtbauprinzip für immobile, tragende Strukturen als auch für wandelbare oder flexible Konstruktionen eingesetzt. So sind beispielsweise Palmenblätter aufgrund ihrer Struktur aus in Längsrichtung verlaufenden – longitudinal – verlaufenden Falten steife aber zugleich auch nachgiebige und veränderbare sowie sehr robuste Gebilde. Marienkäfer können ihre empfindlichen Flügel schützen, indem sie diese unter die Deckschalen einfalten. Im Alltag begegnen uns Faltstrukturen zum Beispiel als Faltenbälge an Zügen und Bussen. Faltkartons nutzen die Wandelbarkeit des Faltprinzips und lassen sich von einem flächigen in einen voluminösen Zustand überführen. Auch im Ingenieurwesen gibt es Faltungen. In der Bautechnik stellen Wellbleche, Trapezbleche und Spundwandprofile gefaltete Halbzeuge dar, im Fahrzeugbau werden Cabriodächer einund ausgefaltet und die Medizintechnik entwickelt Implantate wie Stents, die in den menschlichen Körper eingeführt werden und sich am endgültigen Bestimmungsort auffalten. Faltungen in der Architektur In der Architektur findet das Prinzip des Faltens Anwendung bei weit gespannten Tragwerken, temporären Bauten und bei Fassadenelementen. Bis in die 80er Jahre des letzten Jahrhunderts wurden zahlreiche großmaßstäbliche Faltwerke aus Beton realisiert. Die geodätischen Kuppeln des Architekten Buckminster Fuller (1895-1983) waren große, aus Kunststoffelementen oder aus Metallblechen zusammengesetzte facettierte Kuppeln, deren Geometrie auf Archimedischen Körpern beruhten und als Raumfaltwerke bezeichnet werden. In der zeitgenössischen Architektur findet dieses Leichtbauprinzip leider nur noch selten – manchmal noch in der Messeoder Ausstellungsarchitektur – Verwendung. Da in Zukunft angesichts sich zusehends verknappender Ressourcen dem Thema materialsparender Konstruktionen eine zentrale Bedeutung zukommen wird, lohnt sich die intensive Auseinandersetzung mit dem Strukturformprinzip der Faltung umso mehr. Faltungen und Origami Prinzipien für Konstruktionen in Architektur und Ingenieurwesen Susanne Hoffmann, Martin Trautz

Für Nietzsche konstruiert — ein Dach- und Fassadentragwerk ausgeschnitten aus Brettsperrholz

Die Dach- und Fassadenkonstruktion des Nietzsche-Dokumentationszentrum (NDZ) in Naumburg/Saale ist eine unkonventionelle Anwendung des neuartigen Werkstoffes Brettsperrholz in der Form, dass samtliche Fassaden- und Dachtragwerksteile als fugenlos zusammenhangende und abgewinkelte Rahmenschenkel aus dem Plattenwerkstoff ausgeschnitten wurden. Die Rahmenteile sind im Bereich des geschlossenen Daches im Grundriss versetzt zueinander angeordnet und uber die Dachplatte aus Brettsperrholz, die als elastisches Verbindungselement fungiert, miteinander verbunden. Auf diese Weise entsteht eine ausergewohnliche Konstruktion, die Sehgewohnheiten widerspricht und eine Architektur pragt, die in dieser Weise Bezug auf den Philosophen und seinen kritisch hinterfragenden Geist nimmt. Designed for Nietzsche — A Roof- and Facade-Structure Cut Out from Cross-Laminated Timber-Plates. The structure of the roof and the facade of the Nietzsche-Documentation-Centre in Naumburg/Saale, a small town in the heart of Germany where the philosopher Friedrich Nietzsche spent a major part of his life, is an unconventional application of cross-laminated-timber-plates. It consists of frame elements cut out from the wooden plate-material similar to puzzle-parts sawed out from plywood with a jigsaw. All parts were produced that way and put together with a roofing plate also made from cross-laminated-timber, which works as an elastic longitudinal hinge-element. The structure is a rather unconventional one and refers to the critical and non conformal ideas of the well-known philosopher Friedrich Nietzsche.