Together with Mathias Gmachl (Loop.pH), Daniel Piker (Kangaroo), John Harding (University of Western England) and Will Pearson (McNeel), I will be leading "The Archilace" workshop at the 2015 Design Modelling Symposium in Copenhagen.

DESIGNING, SIMULATING AND MAKING LIGHT COMPOSITE FIBRE STRUCTURES

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This workshop examines the concept of molecular connectivity as model for bending active structures. Participants will be working with state of the art modelling (Grasshopper / Kangaroo 2) as well as second-order FE analysis (Plankton / Karamba FE). The workshop will translate small-scale experiments to architectural design and construction of freeform surfaces.

Methodology:

There are two fundamental approaches to create a stable discretised surface structure: a set of nodes connected into a lattice or an assembly of flat plates, both related to each other through the principle of the lattice-plate dualism: a stable lattice structure can be translated into a stable plate structure by creating its geometrical dual and vice versa (first described by Ture Wester).

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The approach described here is a hybrid of these two principles where a straight, flexible rod is bent into a circle. The bending energy momentum locked into the circle exerts a strong planar force, to create a lattice like building block with a plate potential. By interweaving a number of circles into a continuous surface, a self-supporting, semi-rigid membrane structure can be created that is able to visualise internal stresses and respond to large external stresses without catastrophic failure. Using the technique membranes of highly complex nature can be constructed by hand using only a small set of standard parts. By following a simple ruleset that links surface curvature to member connectivity freeform surfaces, arise from the interaction of bending forces of adjacent parts. Using a realtime physics engine such as Kangaroo it is possible to simulate this process in a digital model or modify the connectivity of triangular meshes, so their duals follow the same rules.

The half-edge library Plankton provides an ideal framework to store and process such meshes as all the core relationships and transformations needed can be implemented by reading the mesh data in different ways without the need to create additional geometry or complex calculations. Using Plankton it is also possible to quickly transform the cellular principle of interwoven circles into a related structure using linear elements woven in three directions. A traditional technique called Kagame from Japan uses a similar logic and has inspired research in carbon nano-structures. The circular and linear technique can also be combined to reinforce each other. Furthermore, the team at Ramboll Computational Design created a FEA model using second-order analysis conducted in real-time with the plug-in Karamba. This integrated approach to modelling and analysis enables the design team to understand buckling behaviour during design exploration as well as inform an intelligent pattern of reinforcement.

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Context:

Archilace is the name of a structural fabrication technique based on lacemaking developed by Loop.pH (Mathias Gmachl & Rachel Wingfield) since 2003. Composite fibres are woven in both continuous lengths and shorter ‘hooped’ lengths into complex geometries based on carbon nano science to create strong, lightweight and flexible adaptive structures.

Loop.pH explore this technique in an architectural context for use as temporary structures, facade technologies and green walls. Archilace is used as a construction and research strategy that explores an eco-mimetic building as a set of hyperbolic, semi-permeable membranes, each enclosing a complex habitat and encouraging exchange with each other and the surrounding environment. Elements specific to the site such as the local ecology, the human community’s skill set and available resources inform a co-authored, open-ended design process. By combining research into resilience theory, topology, new composite materials and traditional textile techniques we aim for the construction of self-supporting, textile membranes of complex geometry without specialist machinery using only a small number of modular parts. This is facilitated by a continuous workflow from parametric drawing to physical simulation to material fabrication.

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Key characteristics:

Strong & Lightweight: Composite fibres combined with smart geometry results in architectural scale structures weighing equal to a person and able to withstand external forces

Modular & Reconfigurable: Made from a small number of modular parts that can be assembled in infinitely different ways

Repairable & Reusable: All parts are temporarily fixed so structures can quickly and easily be taken down and rebuilt elsewhere

Minimal Transportation & Construction: All parts are shipped as linear material assembled by hand on site. No heavy machinery is needed to build on an architectural scale

The workshop will allow participants to:

Learn 2 simple hand-crafting techniques that allow the construction of self-supporting textile membranes using natural and composite materials

Create physical models of such bending active structures using Kangaroo/Joey

Create and modify the underlying n-gon meshes using Plankton for further processing and experimentation

Use Karamba to conduct second-order analysis in real-time and to understand buckling behaviour during design exploration

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Requirements:

Workshop participants are expected to bring laptops and working gloves along. The workshop leaders will provide further material and software prior to the workshop. Participants will work with Carbon and glass-fibre reinforced rods, 3D printing and 2-axis CNC to prepare strip/reel based material for Kagome style weaving.

ComStruct workshop, Tehran, 1-10 August 2015

About ComStruct workshop

The ComStruct workshop was a 10 day workshop on Rhino / Grasshopper / Karamba on computational structures as form generators. It was held in Tehran, Iran at the Contemporary Architecture Association of Iran in early August 2015. The goal of the workshop was to use the finite element plugin Karamba to explore the behaviour of various structural concepts in a digital parametric environment. The work resulted in the design of a pavilion that combined several structural methods made from laser cut aluminium sheets and leather bands as cables.

Introduction

The workshop started with a three day introduction course to parametric design in Grasshopper. Workshop participants were introduced to general computational design methods and grasshopper beginners were taken through the basic principles of NURBS, common shapes and evaluations of curves and surfaces, and scripting with data trees.

The grasshopper introduction was followed by a two day introduction course to the structural analysis software Karamba. Participants were taught how to design stick models for analysis and set up support conditions for various calculation models. Using evolutionary solving algorithms participants learned to optimise several common structural and architectural challenges; from minimising internal forces as bending moments to optimal column layout in a high-rise. Design tools to shape geometry according to structural parameters were introduced to the participants who learned funicular form finding; tension structures and tensegrity; increasing the stiffness – inertia - through geometrical optimisation. Finally participants learned to design with a two-way analysis approach, using structural analysis of an initial design to shape the form of a final design.

The final 3 days participants designed and build a prototype pavilion structure covering a unused and empty swimming pool at the venue. The design development of the temporary pavilion structure incorporated multiple design methods described below.

Concept idea; opposite forces

A design competition amongst the workshop participants lead to the conceptual idea of opposite and reflecting forces; a surface with positive and negative curvature; a shell and a cantilever.

Form finding; a funicular shape that is made to carry its own weight

Optimised forms is often linked with minimising the bending moment. If a structure can carry a load to its supports only by transferring it as axial loads, the thickness of the material can be minimised. To find geometrical forms that work in this way an inverse approach to the problem is often used. In Robert Hooke’s hanging chain principle, a structure that has no bending stiffness hangs from the boundary supports creating a funicular shape as the gravity pulls the chain down. This principle can be extended to work for complex systems, creating structurally efficient vaults and shells when the hanging geometry is inverted.

Many tools are available to perform this simulation, generally known as dynamic relaxation. The most known tools for Rhino / Grasshopper to perform dynamic relaxation are Rhino Vault (BLOCK research group) and Kangaroo (Daniel Piker). In Karamba the simulation and form finding of funicular structures is also possible using the large deformations analysis. Further it is possible to not only find the best shape to respond to the gravity load of a structure, but other external loads can also be used. This can be used to find optimised forms to any given load condition, including multiple load combination situations often found in the real world.

Shaping logics; create a stiff cantilever from

An example that was analysed during the Karamba introduction days was Eduardo Torroja’s “Frontón Recoletos” roof structure. The structure consists of two intersecting barrels, creating a highly efficient two-way spanning structure. In the sort direction the forces are led to the supports through the funicular arch forms of the barrels; more interesting the forces are in the other direction led to the intersection between the barrels that act as a tension area with the top of the barrels acting as the counter compression. The pure geometry with two intersecting barrels makes the geometry hard to deform.

This principle was used in the design development, where several options for curving surfaces of a cantilevering barrel shaped shell structure were tested and which could be instantly analysed in karamba. This instant feedback to the modifications of the design gives the design a fast and effective tool to make informed design decisions.

Folding; increasing inertia of a thin surface

Precedents of origami folding of shell structures includes FOA’s “Yokohama ferry terminal”. Using the same structural logic as the cantilevering barrel, folding a surface in the right way creates inertia and in the same time geometrically interlocking elements. Different folding techniques were tested and analysed and an optimised solution that included both constructability and structural behaviour was derived. The sizes of the panels were optimised for a best fit on the aluminium sheet measuring 1x2m.

Cable truss; using cables to create a truss with thin surface

Cables have been used in engineering design since the first suspension bridges by Thomas Telford and Isambard Brunel; however cable trusses are a relatively new invention from the middle of the 20th century. Cable trusses can be formed in various shapes, many often pre-stressed. By combining a compressive surface layer and compression verticals, cables can form the tension part of a truss.

The concept for this design is to use the thin aluminium plates as compression layer - at it is already form found to be mainly working in compression – and convert it into a truss with a grid of cables offset from the surface. To fix the cables at a set distance from the surface, and acting as the truss “verticals”, cut shapes of the aluminium is bended away from the surface’s plane.

Depth of truss as a function of initial analysis of the thin surface

To set out the height of the truss verticals the initial surface was analysed and the utilisation mapped to surface. The utilisation – the ratio between stress and strength - was then used as a scalar to set the height of the cut triangles on the original surface and then bended to form the truss verticals. The stress utilisation of the aluminium surface shape can therefore be read directly on the geometry as the hole size and height of the folded triangles.

Cable calculations; using the tension/compression eliminator

The folded triangles are connected in a diagrid of thin steel cables. Not all cables are put into tension under ordinary load as self-weight. To check which cables goes slack, Karamba’s tension/compression eliminator was used to remove cable elements from the analysis model that went slack. Several load cases was checked to ensure that all cables are needed.

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In July 2014, together with Klaas de Rycke (Bollinger+Grohmann Paris), Matthew Tam (Bollinger+Grohmann Vienna) and Robert Vierlinger (Bollinger+Grohmann Vienna), I was cluster leader of the 4 day workshop named "The Bearable Lightness of Being" as a part of the Smartgeometry '14 Hong Kong conference hosted at the Chinese University of Hong Kong (CUHK).

The SG Workshop was a unique creative cauldron attracting attendees from across the world of academia, professional practice as well as many of the brightest students. The Workshop was open to 100 applicants who come together for four intensive days of design and collaboration.

The annual Workshop is organised around Clusters. Clusters are hubs of expertise comprising of people, knowledge, tools, materials and machines. The Clusters provide a focus for Workshop participants working together, within a common framework.

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The Bearable Lightness of Being takes its origin in the reflection upon several items; the context of Hong Kong’s urbanity and history, parametric design and open systems, flexible lightweight structures, and Chinese tradition. The goal of the cluster is to design and construct a hyper-flexible, super light-weight and multi-optimised pavilion, through the use of state-of-the-art planning tools as karamba and octopus.

The design must be so light-weight - so optimized - that the pavilion can easily be carried around or take off. The idea of a floating design is based on the tradition of the lit up sky lanterns, an ancient Chinese tradition allegedly originated from Kongming, who is said to have used a message written on a sky lantern to summon help on an occasion when he was surrounded by enemy troops. This cluster is also sending a message; using the city as a platform of events and bringing people together, in a more poetic way countering the hyperindividual through the tactics of events. The modern urbanite is a space in- and e- vader. He does not work out top down solutions but works with and from within the system. The modern urbanite uses the event of being together.

The Bearable Lightness of Being is about designing and producing an event structure, so light-weight that it will be able to be taken for a walk or even fly away.