Mette Ramsgaard Thomsen

Hybrid Tower, Designing Soft Structures

This paper presents the research project Hybrid Tower, an interdisciplinary collaboration between CITA—Centre for IT and Architecture, KET—Department for Structural Design and Technology, Fibrenamics, Universidade do Minho Guimaraes, AFF a. ferreira & filhos, sa, Caldas de Vizela, Portugal and Essener Labor fur Leichte Flachentragwerke, Universitat Duisburg-Essen. Hybrid Tower is a hybrid structural system combining bending active compression members and tensile members for architectural design. The paper presents two central investigations: (1) the creation of new design methods that embed predictions about the inherent interdependency and material dependent performance of the hybrid structure and (2) the inter-scalar design strategies for specification and fabrication. The first investigation focuses on the design pipelines developed between the implementation of realtime physics and constraint solvers and more rigorous Finite Element methods supporting respectively design analysis and form finding and performance evaluation and verification. The second investigation describes the inter-scalar feedback loops between design at the macro scale (overall structural behaviour), meso scale (membrane reinforcement strategy) and micro scale (design of bespoke textile membrane). The paper concludes with a post construction analysis. Comparing structural and environmental data, the predicted and the actual performance of tower are evaluated and discussed.

A Multiscale Adaptive Mesh Refinement Approach to Architectured Steel Specification in the Design of a Frameless Stressed Skin Structure

This paper describes the development of a modelling approach for the design and fabrication of an incrementally formed, stressed skin metal structure. The term incremental forming refers to a progression of localised plastic deformation to impart 3D form onto a 2D metal sheet, directly from 3D design data. A brief introduction presents this fabrication concept, as well as the context of structures whose skin plays a significant structural role. Existing research into ISF privileges either the control of forming parameters to minimise geometric deviation, or the more accurate measurement of the impact of the forming process at the scale of the grain. But to enhance structural performance for architectural applications requires that both aspects are considered synthetically. We demonstrate a mesh-based approach that incorporates critical parameters at the scales of structure, element and material. Adaptive mesh refinement is used to support localised variance in resolution and information flow across these scales. The adaptation of mesh resolution is linked to structural analysis, panelisation, local geometric formation, connectivity, and the calculation of forming strains and material thinning.

Multiscale modeling frameworks for architecture: Designing the unseen and invisible with phase change materials

Multiscale design and analysis models promise a robust, multimethod, multidisciplinary approach, but at present have limited application during the architectural design process. To explore the use of multiscale models in architecture, we develop a calibrated modeling and simulation platform for the design and analysis of a prototypical envelope made of phase change materials. The model is mechanistic in nature, incorporates material-scale and precinct scale-attributes, and supports the design of two- and three-dimensional phase change material geometries informed by heat transfer phenomena. Phase change material behavior, in solid and liquid states, dominates the visual and numerical evaluation of the multiscale model. Model calibration is demonstrated using real-time data gathered from the prototype. Model extensibility is demonstrated when it is used by designers to predict the behavior of alternate envelope options. Given the challenges of modeling phase change material behavior in this multiscale model, an additional multiple linear regression model is applied to data collected from the physical prototype in order to demonstrate an alternate method for predicting the melting and solidification of phase change materials.

Shaping hybrids – Form finding of new material systems

Form-finding processes are an integral part of structural design. Because of their limitations, the classic approaches to finding a form – such as hanging models and the soap-film analogy – play only a minor role. The various possibilities of digital experimentation in the context of structural optimisation create new options for the designer generating forms, while enabling control over a wide variety of parameters. A complete mapping of the mechanical properties of a structure in a continuum mechanics model is possible but so are simplified modelling strategies which take into account only the most important properties of the structure, such as iteratively approximating to a solution via representations of kinematic states. Form finding is thus an extremely complex process, determined both by the freely selected parameters and by design decisions.

Enlisting Clustering and Graph-Traversal Methods for Cutting Pattern and Net Topology Design in Pneumatic Hybrids

Cutting patterns for architectural membranes are generally characterised by rational approaches to surface discretisation and minimisation of geometric deviation between discrete elements that comprise the membrane. In this paper, we present an alternative approach for cutting pattern generation to those described in the literature. Our method employs computational techniques of clustering and graph-traversal to operate on arbitrary design meshes. These design meshes can contain complex curvature, including anticlastic curvatures. Curvature analysis of the design mesh provides the input to the cutting pattern generation method and the net topology generation method used to produce a constraint net for a given membrane. We test our computational design approach through an iterative cycle of digital and physical prototyping before realising an air-inflated cable restrained pneumatic structural hybrid, at full-scale. Using a Lidar captured point-cloud model, we evaluate our results by comparing the geometrical deviation of the realised structure to that of the target design geometry. We argue that this work presents new potentials for membrane expression and aesthetic by allowing free-patterning of the membrane, but identify current limits of the workflow that impede the use of the design method across the breadth of current architectural membrane applications. Nevertheless, we identify possible architectural scenarios in which the current method would be suitable.

Prototyping Practice: Merging Digital and Physical Enquiries

This paper examines the role of the prototyping in digital architecture. During the past decade, a new research field has emerged exploring the digital technology’s impact on the way we think, design and build our environment. In this practice the prototype, the pavilion, installation or demonstrator, has become a shared research tool. This paper asks how this practice has formed by tracing the different roles of the prototype from ideation and design, to analysis and evaluation. Taking point of departure in CITA’s own prototyping practice, we explore the relationships between physical and digital prototyping as a particular means of validation and verification. Here, a breadth of physical prototypes take on varying roles, in turn informing, testing and proving the research enquiry. The paper addresses how we can differentiate between these modes of prototyping and how.

An Integrated Modelling and Toolpathing Approach for a Frameless Stressed Skin Structure, Fabricated Using Robotic Incremental Sheet Forming

For structural assemblies that depend upon robotic incremental sheet forming (ISF) the rigidity, connectivity, customization and aesthetics play an important role for an integrated and accurate modeling process. Furthermore, it is critical to consider fabrication and forming parameters jointly with performance implications at material, element and structural scales. This paper briefly presents ISF as a method of fabrication, and introduces the context of structures where the skin plays an integral role. It describes the development of an integrated approach for the modelling and fabrication of Stressed Skins, an incrementally formed sheet metal structure. The paper then focus upon the use of prototypes and empirical testing as means to inform digital models about fabrication and material parameters including: material forming limits and thinning; the parameterisation of macro and meso simulations with calculated and observed micro behaviour; the organisation and extraction of toolpaths; and rig setup logics for fabrication. Finally, the validity of these models is evaluated for structural performance, and for geometric accuracy at multiple scales.