Jan Knippers

Design and construction principles in nature and architecture

This paper will focus on how the emerging scientific discipline of biomimetics can bring new insights into the field of architecture. An analysis of both architectural and biological methodologies will show important aspects connecting these two. The foundation of this paper is a case study of convertible structures based on elastic plant movements.

Flectofin: a hingeless flapping mechanism inspired by nature

This paper presents a novel biomimetic approach to the kinematics of deployable systems for architectural purposes. Elastic deformation of the entire structure replaces the need for local hinges. This change becomes possible by using fibre-reinforced polymers (FRP) such as glass fibre reinforced polymer (GFRP) that can combine high tensile strength with low bending stiffness, thus offering a large range of calibrated elastic deformations. The employment of elasticity within a structure facilitates not only the generation of complex geometries, but also takes the design space a step further by creating elastic kinetic structures, here referred to as pliable structures. In this paper, the authors give an insight into the abstraction strategies used to derive elastic kinetics from plants, which show a clear interrelation of form, actuation and kinematics. Thereby, the focus will be on form-finding and simulation methods which have been adopted to generate a biomimetic principle which is patented under the name Flectofin®. This bio inspired hingeless flapping device is inspired by the valvular pollination mechanism that was derived and abstracted from the kinematics found in the Bird-Of-Paradise flower (Strelitzia reginae, Strelitziaceae).

Stability of grid shells

Abstract Grid shells exhibit different modes of stability failure. This paper explains some parameters influencing the failure load of domes and barrel vaults and makes suggestions for the imperfection shape which has to be assumed in an analysis. All computations are carried out with a commercial FE-program.

Active Bending, a Review on Structures where Bending is Used as a Self-Formation Process:

In this paper structures that actively use bending as a self-forming process are reviewed. By bringing together important material developments and various historical as well as recently built samples of such structures, the aim is to show coherences in their design approach, structural systems and behaviour. Different approaches to bending-active structures are defined and described. By making this work accessible and categorising it, this paper aims to contribute to an emerging development. A differentiation of such structures is suggested based on their design approaches. Three such approaches are differentiated: the behaviour based approach, the geometry based approach and current research that seeks to integrate the two. In this paper the nature of these approaches and some important project samples are discussed.

A methodology for transferring principles of plant movements to elastic systems in architecture

In architecture, kinetic structures enable buildings to react specifically to internal and external stimuli through spatial adjustments. These mechanical devices come in all shapes and sizes and are traditionally conceptualized as uniform and compatible modules. Typically, these systems gain their adjustability by connecting rigid elements with highly strained hinges. Though this construction principle may be generally beneficial, for architectural applications that increasingly demand custom-made solutions, it has some major drawbacks. Adaptation to irregular geometries, for example, can only be achieved with additional mechanical complexity, which makes these devices often very expensive, prone to failure, and maintenance-intensive.Searching for a promising alternative to the still persisting paradigm of rigid-body mechanics, the authors found inspiration in flexible and elastic plant movements. In this paper, they will showcase how todays computational modeling and simulation techniques can help to reveal motion principles in plants and to integrate the underlying mechanisms in flexible kinetic structures. By using three case studies, the authors will present key motion principles and discuss their scaling, distortion, and optimization. Finally, the acquired knowledge on bio-inspired kinetic structures will be applied to a representative application in architecture, in this case as flexible shading devices for double curved facades. Plant movements.Kinetic structures.Biomimetics.Facade shading.Compliant mechanisms.

Bridges with Glass Fibre-Reinforced Polymer Decks: The Road Bridge in Friedberg, Germany

In July 2008, the first road bridge in Germany using glass fibre-reinforced polymers (GFRP) was completed in Friedberg/Hessen. The structure has a span of 27 m and acts as a flyover across the federal road B3. The high durability of the new construction material and the fast assembly of the bridge were decisive factors in favour of GFRP. During the preceding years, several lightweight bridges using FRP had been constructed in the USA, Japan and also in Europe. Through these projects, valuable experience was gathered regarding construction, and the use and performance of composites could be demonstrated. The bridge in Friedberg extended this experience by taking into account the composite action between the FRP deck and the steel girders. It also followed, consequently, the approach of durable bridge construction by omitting any bearings or expansion joints and making the innovative material visible to passers-by.

Fibrous structures: An integrative approach to design computation, simulation and fabrication for lightweight, glass and carbon fibre composite structures in architecture based on biomimetic design principles ☆

Abstract In this paper the authors present research into an integrative computational design methodology for the design and robotic implementation of fibre-composite systems. The proposed approach is based on the concurrent and reciprocal integration of biological analysis, material design, structural analysis, and the constraints of robotic filament winding within a coherent computational design process. A particular focus is set on the development of specific tools and solvers for the generation, simulation and optimization of the fibre layout and their feedback into the global morphology of the system. The methodology demonstrates how fibre reinforced composites can be arranged and processed in order to meet the specific requirements of architectural design and building construction. This was further tested through the design and fabrication of a full-scale architectural prototype.

From Nature to Fabrication: Biomimetic Design Principles for the Production of Complex Spatial Structures

In the current paper the authors present a biomimetic design methodology based on the analysis of the Echinoids (sea urchin and sand dollar) and the transfer of its structural morphology into a built full-scale prototype. In the first part, an efficient wood jointing technique for planar sheets of wood through novel robotically fabricated finger-joints is introduced together with an investigation of the biological principles of plate structures and their mechanical features. Subsequently, the identified structural principles are translated and verified with the aid of a Finite Element Model, as well as a generative design system incorporating the rules and constraints of fabrication. The paper concludes with the presentation of a full-scale biomimetic prototype which integrates these morphological and mechanical principles to achieve an efficient and high-performing lightweight structure.

Biomimetic Lightweight Timber Plate Shells: Computational Integration of Robotic Fabrication, Architectural Geometry and Structural Design

The research presented in this paper pursues the development and construction of a robotically fabricated, lightweight timber plate system through a biologically informed, integrative computational design method. In the first part of the paper, the authors give an overview of their approach starting with the description of the biological role model and its technical abstraction, moving on to discuss the computational modelling approach that integrates relevant aspects of biomimetics, robotic fabrication and structural design. As part of the validation of the research, a full-scale, fully enclosed, insulated and waterproof building prototype has been developed and realized: The first building featuring a robotically fabricated primary structure made of beech plywood. Subsequently, the methods and results of a geodetic evaluation of the fabrication process are presented. Finally, as the close collaboration between architects, structural and geodetic engineers, and timber fabricators is integral to the process, the architectural and structural potentials of such integrative design processes are discussed.

Recent Developments in the Design of Glazed Grid Shells

Free-form geometries are very popular in todays architecture. Computer controlled fabrication methods allow for structures, which would not have been possible a few years ago. But how does one transfer 3D geometries into a load bearing structure without loosing the architectural vision of smoothly shaped building envelopes? An intense discussion is necessary to navigate architectural visions of elegant 3D shapes through the technical and economic constraints of realization. The role of the engineer is conceived as that of a mediator between the aesthetic ambitions of the architect, the budget of the client and the technical capabilities of the contractor. From the very early stages of form finding to the assembly on site, a consistent design process is absolutely necessary to achieve high quality free formed structures. In this paper different examples are presented to demonstrate this. The projects vary from a single layer grid shell for Westfields new shopping centre at White City, London and a large space structure in Frankfurt to a timber shell for a department store in Cologne