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Super Composite: Carbon Fibre Infused 3D
Printed Tectonics
H. Mohamed1,D.W.Bao
2, and R. Snooks1(B)
1Royal Melbourne Institute of Technology (RMIT), Building 100, Melbourne 3000, Australia
{hesam.mohamed,roland.snooks}@rmit.edu.au
2Centre for Innovative Structures and Materials, School of Engineering, RMT University,
Melbourne 3001, Australia
nic.bao@rmit.edu.au
Abstract. This research posits an innovative process of embedding carbon fibre
as the primary structure within large-scale polymer 3D printed intricate architec-
tural forms. The design and technical implications of this research are explored and
demonstrated through two proto-architectural projects, Cloud Affects and Unclear
Cloud, developed by the RMIT Architecture Snooks Research Lab. These projects
are designed through a tectonic approach that we describe as a super composite
– an approach that creates a compression of tectonics through algorithmic self-
organisation and advanced manufacturing. Framed within a critical view of the
lineage of polymer 3D printing and high tech fibres in the field of architectural
design, the research outlines the limitations of existing robotic processes employed
in contemporary carbon fibre fabrication. In response, the paper proposes an app-
roach we describe as Infused FibreReinforced Plastic (IFRP) as a novel fabrication
method for intricate geometries. This method involves 3D printing of sacrificial
formwork conduits within the skin of complex architectural forms that are infused
with continuous carbon fibre structural elements. Through detailed observation
and critical review of Cloud Affects and Unclear Cloud (Fig. 2), the paper assesses
innovations and challenges of this research in areas including printing, detailing,
structural analysis and FEA modelling. The paper notes how these techniques
have been refined through the iterative design of the two projects, including the
development of fibre distribution mapping to optimise the structural performance.
Keywords: 3D printing ·Fibre composite ·Additive manufacturing
1 Introduction
The focus of this paper is the application and development of a series of technical
innovations that enable the design and realisation of complex, intricate architectural
forms through a carbon fibre reinforced 3D printed polymer fabrication approach. This
Infused Fibre Reinforced Plastic (IFRP) method offers a viable approach to construct-
ing super composites that have intrinsically complex geometries and compressed tec-
tonics. This strategy is part of a larger trajectory of design research undertaken by the
Snooks Research Lab that explores the compression of the tectonic relationship between
skin, structure, services, and ornament, through the composite fabrication of intricate
algorithmic architecture (Snooks 2020) (Fig. 1).
© The Author(s) 2021
P. F. Yuan et al. (Eds.): CDRF 2020, Proceedings of the 2020 DigitalFUTURES, pp. 297–308, 2021.
https://doi.org/10.1007/978-981-33-4400-6_28
298 H. Mohamed et al.
Fig. 1. Cloud Affects, 2019, detail photographs, Snooks Research Lab.
This research contributes to a growing international body of work and community of
architects who are exploring the application of 3D printing in architecture. The research
presented here has evolved from an exploration of the design implications of 3D printed
translucent plastics and how these can be reinforced to enable their robust application to
architecture. While Fused Deposition Modeling (FDM) is a relatively mature 3D print-
ing technology, its application to large-scale architectural fabrication requires numerous
innovations in terms of hardware, printing techniques, software development, architec-
tural detailing, structural design, and the design of tectonics. This paper outlines some of
these developments including printing topologically complex forms, the subdivision of
form into printable parts, non-parallel printing techniques, the infusion of carbon fibre
within printed conduits, structural analysis and design of carbon-infused plastic parts
and jointing systems.
2 Context
2.1 Fibre Composites in Architecture
Advancements in compounding and fabrication techniques have paved the way for syn-
thetic polymer composites to be deployed as a new building material. While the use of
fibre composites in architecture dates to at least 1956 with the Monsanto House, recently
there has been a re-emergence of polymer composites in architectural construction and
discourse. This is evident in the work of architects such as Greg Lynn; with a long track
record of innovative applications of composites through which he has realised complex
curvature architectural forms. He describes “intricacy” as a tectonic relationship between
elements with the continuous and gradient change to produce a dynamic spatial effect
Super Composite: Carbon Fibre Infused 3D Printed Tectonics 299
(Lynn and Friedman 2003). Lynn envisages a shift in architectural fabrication in which
fusion by heat and chemical attachment replaces assemblage through mechanical con-
nections (Lynn 2011a,b). Use of fibre reinforced polymer composites in Lynn’s work
allows for the gradual transformation of geometry to expose structure and alignment of
load paths with the flow of surface.
2.2 Robotic Fabrication and High-Tech Fibre Structures
The repetition in production of fibre composite parts laminated onto traditional moulds
create considerable efficiencies in sectors such as the marine industry to invest in reusable
moulds. However, the architectural application of this approach is problematic when
there is little repetition as the cost of the mould becomes prohibitive. Over the past
decade architectural research groups including the Institute of Computational Design
and Construction (ICD) in Stuttgart, and the Digital Building Technologies (DBT) lab
at the ETH in Zurich have developed new robotic techniques for the fabrication of fibre
reinforced polymers that avoid the use of moulds. These techniques, and the projects
they are applied to, are important precursors to the research posited here. However,
they embed specific limitations on architectural form. The ICD Stuttgart fibre winding
projects, including the Research Pavilion (2010) and Buga Fibre Pavilion (2019) use
customised jigs to create ruled surface geometry. An alternative approach explored by
the ICD is robotic taping/gluing of a fibre structure to a temporary inflatable formwork
(Doerstelmann et al. 2014). The DBT lab at ETH has experimented with a two-step
fibre reinforcement of 3D printed form, where a composite of polymer and fibre is
extruded directly on to a 3D printed base geometry (Kwon et al. 2019). Although this
CFRP technique advances design research into fibre reinforced polymer structures, this
method limits the topological scale and intricacy of the architectural forms that can be
fabricated.
2.3 Big Area Additive Manufacturing
This paper is focused on Fused Deposition Modelling (FDM) of polymers within the field
of additive manufacturing, also known as 3D printing. Big Area Additive Manufacturing
or (BAAM) refers to the fabrication of large-scale components through FDM techniques.
In the past few years, BAAM has become a desirable technique for relatively fast and
efficient fabrication of components in different industries such as aerospace, automotive,
product design and more recently within the fields of architectural design and building
construction.
300 H. Mohamed et al.
Fig. 2. Cloud Affects, 2019 (Left), and Unclear Cloud, 2020 (Right), Snooks Research Lab.
3 Methodology: Intricate Tectonics and Composite Fabrication
3.1 Super Composite
This research extends the concept of composites from material (fibre composite) to tec-
tonics by compressing surface, structure, services and ornament into a single irreducible
assemblage – a super composite (Fig. 3). This strategy is leveraged to develop intricate
tectonics for expressive architectural forms. The super composite approach is designed
through an agentBody self-organising generative algorithmic process that draws on the
logic of swarm intelligence. It operates through multi-agent systems (agentBody algo-
rithms form part of the Behavioral Formation design methodology developed by Roland
Snooks since 2002). The agentBody generative design process simultaneously creates
both the structure and form, as the agentBody consists of a skin and embedded structural
skeleton (Snooks et al. 2020). The fabrication logic of the super composite leverages the
geometric capacity of 3D polymer printing and the structural capacity of carbon fibre.
3.2 A Lineage of 3D Printed Sacrificial Formwork Projects
A super composite is a 3D printed hybrid of skin and embedded structural conduits that
are infused or cast with structural material. The precursor to this approach was developed
through a series of projects beginning with the NGV Pavilion (2016) Hawthorn Public
Art (2016) by Studio Roland Snooks. These projects developed a tectonic, based on the
logic of 3D printed sacrificial moulds, or formwork, into which high strength concrete
structural elements were cast (Fig. 4) (Snooks 2018). This research has more recently
been expanded to explore the implications of infusing carbon fibre into 3D printed
sacrificial formwork conduits through the Cloud Affects and Unclear Cloud projects.
The infusion of carbon fibre within 3D printed conduits represents a novel approach to
fibre composite fabrication that departs from the contemporary carbon fibre fabrication
approaches, such as fibre winding and taping described above. Instead, this research
employs a fibre infused sacrificial formwork technique to create a negotiated relationship
between the inner and outer skins where form and structure negotiate one another to
enable intricate topologically complex forms.
Super Composite: Carbon Fibre Infused 3D Printed Tectonics 301
Fig. 3. Super composite: compressed structure, services, and skin
Fig. 4. Concrete infused sacrificial formwork, NGV Pavilion, 2016, Studio Roland Snooks
302 H. Mohamed et al.
3.3 Sacrificial Formwork for Carbon Fibre Infusion
In this approach, a multilayered sacrificial formwork, or mould, is used to accommodate
both structure and services within embedded conduits. This creates a complex lattice net-
work which is made from a, primarily tensile, structural skeleton at the core surrounded
by a secondary layer to allow for building services and compression foam insulation.
This lattice network is embedded in a translucent outer skin. These two inner and outer
skins laminate to one another periodically and are connected through flange geometries
to create sufficient structural integrity in the skin at the macro scale (Fig. 5right).
Fig. 5. 3F printed sacrificial formwork (left), preparation for carbon infusion (right)
Within the inner printed conduit, continuous carbon fibre elements are positioned
and infused with an epoxy resin bonding the carbon fibre, steel connections and polymer
sacrificial mould (Fig. 6).
Fig. 6. Customised jigs for steel connections (left), assembly division & joints (right)
Super Composite: Carbon Fibre Infused 3D Printed Tectonics 303
3.4 BAAM Techniques and Geometric Implications
Advancement in BAAM processes at the RMIT robotics lab in recent years has enabled
the realisation of large scale algorithmically designed architectural prototypes such as
Cloud Affects. Some of these technical enhancements, like improved start-stop printing
and non-parallel/non-horizontal layer printing, are necessary to achieve substantial topo-
logical freedom of geometry and extreme cantilevering capacity. These improvements
have also posed new challenges to the 3D printing process.
3.4.1 3D Printing Non-continuous Surfaces
Robotic polymer pellet extruding enables relatively fast 3D printing through a high
material flow rate. However, compared to filament printing, there is no material retraction
in this process when a tool path stops. This results in the dragging of excess material
between the endpoint of a tool path and the subsequent start point, creating polymer
strings within the printed part. These strings cause accumulated defects between layers,
affect the surface quality and results in possible print failure in large prints. Despite
challenges created by this basic issue, start-stops are necessary for the fabrication of
non-continuous surfaces, in particular surfaces with topological complexity. Through
a design and fabrication feedback loop, this research introduced a new technique to
resolve this by using flange connections between the independent layers of structure,
services and skin conduits. This technique minimises the strings within the geometry
by minimising start-stops and maximising continuous toolpath length, which results in
enhanced print quality. As well as surface quality improvement, these flange connections
increase structural connections between the conduits and transfer the loads more evenly
to the fibre structure located in the core conduit.
3.4.2 Directionality, Geometric Freedom and Extreme Cantilevering
Conventional FDM printing where each layer is deposited horizontally, and perpendic-
ular to the vertical axis of the tool, poses significant limitations to geometrical direction-
ality. Small layer width to height ratios in large-scale polymer printing is essential to
keep the weight of the 3D printed components down. However, this reduces the capacity
to print cantilevering geometries with large draft angles. Non-parallel printing leverages
the 6 axes of the robot to deposit non-horizontal layers in order to gradually change the
layer heights and print plane orientation within the printing process. This enables the fab-
rication of geometries with more complex surface directionality and higher draft angles.
This technique accompanied by temporary printed support material enabled significant
cantilevers in the Cloud Affects project (Fig. 7).
These advancements require high accuracy and calibration for both hardware and
software tools. Over the past 6 years of research and development, the RMIT robotics lab,
in collaboration with industry partners, has developed several generations of polymer
extruders with high accuracy and large deposition capacity. The latest generation of these
extruders implements new functions and technical capacities such as a new shut-off valve
system to reduce polymer strings as well as multiple heating and cooling zones in the
extrusion barrel for controlled melting of the polymer. These hardware improvements
have been in parallel with the development of software to better control and diagnose all
304 H. Mohamed et al.
Fig. 7. Non-parallel printing (left), draft angle analysis (right)
aspects of the printing process, across multiple robotic platforms, materials and extruder
types.
3.5 Structural Design Implications
The posited super composite of 3D printed polymer with infused carbon fibre struc-
tural members creates an integral link between the form, articulation and structure of
the project. This requires both the geometry of the agentBody and its computational
behavior to be designed through structural heuristics and their interaction with FEA
analysis (Snooks 2020). This process establishes an inherently structural lattice which
is subsequently fine-tuned and sized through an FEA analysis approach. This process
evolved through the two projects to increase the accuracy of the analysis and efficiency
of the structure.
Fig. 8. Real-time structural feedback for fine-tuning of the amount and position of carbon fibre
(front view)
Super Composite: Carbon Fibre Infused 3D Printed Tectonics 305
The structural setup of the two projects consists of an irregular cantilevering carbon
fibre structure with prefabricated steel connections. Our approach to Cloud Affects was
to simulate the stresses in the structural members. The overall shape of the structure
is analysed as a truss successively using the FEA tools Millipede and Abaqus. We
examined the structural strength of the assembly at the early form-finding stages using the
Millipede in Rhino/Grasshopper platform. Global deformations and bending moments of
the structure have been calculated and simulated for real-time fine-tuning of the carbon
fibre sizing during the schematic design phase. This analysis took the overall weight
of the structure, material properties of the resin and fibre and connection locations
into account to calculate values of deformation at the extremes of the structure, where
there is significant cantilevering. These simulations also determined the variable bending
moments throughout the structure, the higher zones of stress indicated in red in Fig. 8,
which enabled the distribution of variable section sizes of the carbon fibre elements.
Later, we collaborated with the RMIT Center for Innovative Structures and Materials to
calculate the structure in the phase of design development using the engineering FEA tool
Abaqus. As opposed to the bending simulation in Grasshopper Millipede, the explicit-
dynamic analysis in FEA engineering software, Abaqus provided more accurate results
for the design development. It offered the simulation and analysis of the bending process
and values of maximum magnitude, mean stress and displacement by including different
parameters such as overall structure weight, proportions of carbon fibre to resin, steel
properties and other related boundary conditions. The gradient colour legend indicates
the range of values for structural analysis result (Fig. 9). The accurate data helped us
refine the design to ensure the appropriate safety and redundancy.
Fig. 9. Accurate simulation & in-depth analysis of carbon fibre structure (rear view)
Although this analysis enabled us to design the overall structure by ballparking
the deformation amount and weak moments of the structure, this method considers
the carbon fibre as the only structural element, deliberately ignoring the strength of
the 3D printed geometry to simplify the FEA approach. It, therefore, overestimated the
required structural strength of the carbon fibre composite, resulting in oversized structural
conduits, carbon fibre cross-section, resin volume and steel connections. Consequently,
this process has been refined in the Unclear Cloud project for which we have developed a
hybrid analysis that includes both the carbon fibre network and the compressive capacity
306 H. Mohamed et al.
of the polymer skin. This improvement in the simulation of the structure is helping us
to create an accurate estimation of the required structural strength to reduce the amount
of polymer, resin and fibre needed for the project.
The carbon fibre elements infused within the 3D printed conduits are continuous
while the network analysis is undertaken as discrete segments of the structural lattice.
Consequently, the discrete segments cannot be optimally sized without consideration
of the continuous extent of the carbon element. This has led to the development of an
approach, which we describe as fibre mapping, that optimises the layout of the continuous
carbon fibre elements. This approach maps, or navigates, the fibres through the network
relative to the specific bending moments of the discrete segments. This was initially
developed as a manual iterative process in the Cloud Affects, before being encoded into
an algorithmic approach in the Unclear Cloud project (Fig. 10).
Fig. 10. Fibre mapping (right), improved bending moments (left)
3.6 Jointing
Logistics and polymer printing size limitations of the two projects require prefabricat-
ing parts which are assembled. Connecting these individual parts creates a substantial
challenge and need for robust joints that create a continuity of structure equal to the
strength of the carbon fibre elements. Other polymer printing issues such as shrinkage
and warpage increase these challenges by creating uneven joints between panels. One
approach in dealing with this issue is to overlap and conceal the seam lines with a built-in
tolerance to connect individual panels side by side, horizontally. This method was used
in a number of previous projects, including SensiLab, and B515 Studios (Snooks et al.
2020). The issue with this approach is the lack of structural continuity between panels.
Another previous project, Floe (2018), used a continuous structural network fabricated
from folded steel plates and a shingle-style arrangement of 3D printed polymer pan-
els overlapping each other and connecting only to the steel sub-structure – not to one
another. This method overcomes the issue of warpage and shrinkage by overlapping the
Super Composite: Carbon Fibre Infused 3D Printed Tectonics 307
panels at the edges where maximum warpage and shrinkage occurs during the printing
process. However, the steel structure and mechanical connections are exposed, creating
a disruption to the fluidity of the form and establishing discrete structure and skin. Cloud
Affects overcomes this by using concealed steel fixing plates that create structural con-
tinuity across panel joints. In this method the integrity of the structure is preserved by
creating a physical bond between infused carbon fibre and steel, the steel connections are
concealed within the structural conduits and are connected to each other mechanically
with minimum disruption to the skin surface. A mechanical fixing method was required
for this project as it needed to be assembled and disassembled at multiple sites (Fig. 11).
Fig. 11. Steel plate wall connection (left), implanted steel connections (right)
4 Conclusion
This research has outlined an approach to integrating carbon fibre structure within 3D
printed polymer skins. This novel super composite strategy, of infusing carbon fibre
within sacrificial formwork conduits, has evolved through a lineage of research projects
at the Snooks Research Lab and contributes to a larger community of architects explor-
ing robotic approaches to fabricating carbon fibre structures. To advance this research,
we have developed innovative techniques and approaches in large-scale 3D printing,
detailing necessary to infuse carbon fibre, and advances in digital tools to fabricate the
necessary geometric complexity. The future direction of this work is intended to extend
the research beyond proto-architectural demonstrator projects and explore the feasibility
of this approach within the design and construction of larger-scale architectural projects.
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