Bio-Integrative Structure

POLYBRICK 2.0: Bio-Integrative Load Bearing Structures

Eda Begum Birol1, Yao Lu1, Ege Sekkin1, Colby Johnson2, David Moy2, Yaseen Islam2, Jenny Sabin1
1JSLab, Department of Architecture, AAP, Cornell University
2Department of Mechanical Engineering, Cornell University

1 Various PolyBrick 2.0 prototype geometries: Fabrication is carried through with aid of Formlabs Form 2 ceramic resin printer, prototypes are then bisque fired at cone 06 and glaze fired at cone 4 in medium speed.

Natural load bearing structures are characterized by aspects of specialized morphology, lightweight, adaptability, and a regenerative life cycle. PolyBrick 2.0 aims to learn from and apply these characteristics in the pursuit of revitalizing ceramic load bearing structures. For this, algorithmic design processes are employed, whose physical manifestations are realized through available clay/porcelain additive manufacturing technologies (AMTs).

2 Diagrammatic representation of the initial sphere packing (a) followed by lattice generation through the employment “Kissing spheres” algorithm (b)
3 Workflow diagram with initial sphere packing algorithm consisting of interpretation of trabecular number and trabecular separation parameters as sphere number within a bounding box and sphere radii, respectively as marked

By integrating specialized expertise across disciplines of architecture, engineering, and material science, our team proposes an algorithmic toolset to generate PolyBrick geometries that can be applied to various architectural typologies.

Additionally, comparative frameworks for digital and physical performance analyses are outlined. Responding to increasing urgencies of material efficiency and environmental sensibility, this project strives to provide for designers a toolset for environmentally responsive, case-specific design, characterized by the embedded control qualities derived from the bone and its adaptability to specific loading conditions.

4 Process diagram from the stage of lattice generation (a-b) to uniform thickening; (c) Illustrated is a workflow whereby a bounding box of 38 mm x 38 mm x 38 mm is packed with uniform spheres of 3 mm radii, the resulting lattice beams are then thickened uniformly by 1.5 mm in radius. A theoretical lateral load of 100 kN is then applied to the lattice system; (d) The resulting stress values are calculated (e) along strut lengths; Thickening values are established as a direct function of these varying stress values and realized through a Cocoon based Grasshopper script (f)

Various approaches to brick tessellation and assembly are proposed and architectural possibilities are presented. As an outcome of this research, PolyBrick 2.0 is effectively established as a Grasshopper plug-in, “PolyBrick” to be further explored by designers.

“Ceramic modules of standard measurement have been used as a building block […] for many centuries” (Sabin 2014). With rapid developments in the area of clay additive manufacturing, there is an emerging possibility to reintroduce non-standard clay building blocks in load bearing applications.

5 MATLAB based ellipsoid packing visualization: Ellipsoids are oriented towards the maximum principal stress direction on their larger axis, to increase structural capacity of the system by responding to directionality
6 (1) Closest distance is hard to calculate when two ellipsoids are not close to parallel; (2)” Small angle assumption” simplifies the calculation of the closest distance of two ellipsoids

The motivation for such research trajectories comprise of “a qualitative, design driven desire for novel forms, or an aspiration for the quantitative improvement of building performance metrics” (Seibold et al. 2018). However, literature outlining expansive utilization of these technologies within comprehensive processes of algorithmic generation, manufacturing, digital and physical evaluation, and architectural application remains lacking.

7 Close-up images of the physical prototypes showing the spatial and architectural possibilities created through varying levels of porosity present in PolyBrick 2.0 geometries
8 Snippet from the video recording of Instron compressive tests of the Kangaroo based sphere packing prototypes

As part of comprehensive workflow for PolyBrick 2.0, novel algorithmic processes are developed, fabrication methods are outlined, prototype performances are evaluated, and architectural applications are envisioned. Hence, PolyBrick 2.0 suggests a complete methodology in continuing PolyBrick’s ubiquitous aim to “bridge digital processes with the production and design of nonstandard ceramic building blocks in architecture” (Sabin et al. 2014).

9 Full-scale workflow: Stress direction(01) is used to interpolate compressive and tensile curves (07) that form global stress lines(08), which are then overlaid with the stress magnitude data (08) to form a speculative tessellation(10). Tessellated units are then individually packed (11) using our custom algorithm and intersection points (18) are utilized to achieve a seamless packing (19).

Within this process the role of “non-standard” components in load bearing applications is addressed and the duality of solidity and porosity in relation to structural performance is explored.

10 (a) Speculative wall condition with transferred wind loads of 40 kg/m2, a point load of 3100 kg and self- weight were applied. (b) Generated colored mesh with color values correlating to stress magnitude date extracted from ANSYS simulation.

We expand upon pursuits to implement additive manufacturing tools (AMTs) in revitalizing ceramic load bearing structures in more materially efficient and responsive contexts. A precise and complete workflow is outlined and formalized as a Grasshopper plug-in, “PolyBrick,” accompanied by a custom C# tessellation algorithm is established for further implementation by users and designers.

11 Peak force (N) values for models that are generated using the Kangaroo based sphere packing (left) and C# based custom sphere packing lattices (right); Generated prototypes vary in sphere radii and strut thickness, and in both cases increasing strut thickness and decreasing sphere radii amount to increased peak load value
12 Load (N); Displacement (mm) curves for Kangaroo based sphere packing (left) and C# based custom sphere packing lattices (right); C# based sphere packing lattices have higher peak load values (N) and derived stiffness values (N/mm) as recorded; Derived stiffness values are used to calculate material efficiency for comparison between PolyBrick and solid cube prototypes

The trajectory of the research introduces a design process emphasizing adaptability and lightweight, with various potential strategies that relate to environmental responsiveness and programmatic concerns.

13 (top left) Prototype of one brick tessellation component from suggested speculative wall: the boundary condition of the brick component corresponds to the principle stress lines; (top right) Zoomed in shot of tesselation boundaries; (bottom) Model illustration of assembly process possibility

We follow a rigorous process of performance analysis with potential to be implemented in future workflows incorporating AMTs. Outlined processes of evaluation strengthen the argument for the implementation of non-standard, porous ceramic building components as a viable material for load bearing/architectural application.

14 Digital representation of full scale wall proposal based on aforementioned loading condition
15 (left) Diagrammatic PolyBrick Lattice in curved geometry; (middle) Applied lattice thickening visualized digitally; (right) 3D printed diagrammatic model

Hence, PolyBrick offers a non-standard, light weight, and efficient load bearing material system alternative to current construction methodologies. The integral role of porosity opens up potential for further design exploration and integration of additional material systems.

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