Mixed Matters

The Epistemology of Designing with Functionally Graded Materials

In contrast to composites, which are effectively laminates, functionally graded materials (FGM) are singular multi-materials that vary their consistency gradually over their volume. As their use is expected to become increasingly prevalent in fabrication and construction, the research explores a future where ‘true’ continuity will eventually be enabled in architecture through the merging of different materials that will be fused together three-dimensionally. The specific focus in this context is to propose a revised design methodology that corresponds to these changes in building technique, repositioning material behaviour as an integral and defining part of the design process. The anticipated outcome of the thesis is a new design manual that defines a procedure that can be followed in order to design continuously graded material constructs. Within this domain there are two main parameters that are conceptualised, specified, analysed and utilised to design with.

Firstly, due to the nature of continuously graded structures (consisting of no mechanically joined parts), there are/will be two main methods for in-situ construction: through three-dimensional printing, or through material poured and treated into its liquid form in order to generate larger materially blended constructs. In either of these cases, material behaviour needs to be taken into account and prioritised in the design decision hierarchy. The incorporation of this through the use of digital simulations becomes essential to the design process. In simulating material fusion, the main focus is to formulate a corresponding epistemology in which criteria for the material selection, appropriate forces and computational agency and methods for evaluating the results are established. In terms of material selection, the objective is to verify fusion compatibility of two or more substances through existing research paradigms in material science. Regarding the affecting agency, the separation of invasive versus non-intrusive processing techniques informs the assignment of simulation parameters pertaining to the latter, while structural and aesthetic criteria are in place to evaluate and potentially rethink the initial simulation set out.

Secondly, digitally simulating materials in their liquid state implies the use of a containing geometry within which fusion will occur. An additional focus it to effectively define the formal characteristics of the containing vessels. These are informed by instances of naturally occurring functionally graded materials and principles for dissimilar material attachments such as ‘interdigitation’ (on a macro-scale), as well as shallow angle and multiple attachment sites of one material into another (on a miniature/visible-scale). In addition, the form and orientation of the mould and the material compartments are aligned/coordinated with the structural properties of the substances to be fused.

Effectively, the research question is formulated in how can research on functionally graded materials (as found in nature and through studying FGM manufacturing techniques) inform new methods of designing the materially continuous (avoiding tectonic thinking through the direct blending of digitally simulated matter). A further sub question is how can tectonic elements, such as curtain wall glazing parts be (re)designed using multi-materials.