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Hybrid formation: tension-based assembly system for bending- active plate structures

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Abstract

This paper investigates a novel assembly system that employs tension force to transform initially planar elements into bending-active plate structures. Tension is applied through cables connecting bending-active elements. The elements are designed through form planarization, tessellation, and stripe definition on an input geometry. The system offers the benefit of reduced joinery sequences by having minimum tension cables operating in both the joinery and assembly process. Moreover, since there is a correlation between the tessellation process and the arrangement of the cables on the input geometry in the proposed assembly system, this research followed a design-to-assembly workflow. This workflow includes a set of digital tools and various physical tests in small and large scale. Finally, the paper discusses the practicality of the system and further potentials.
Proceedings of the IASS Annual Symposium 2020/21 and
the 7th International Conference on Spatial Structures
Inspiring the Next Generation
23 27 August 2021, Guilford, UK
S.A. Behnejad, G.A.R. Parke and O.A. Samavati (eds.)
Copyright © 2021 by the author(s) as listed above. Published in the Proceedings of the IASS Annual Symposium
2020/21 and the 7th International Conference on Spatial Structures, with permission.
Hybrid formation: tension-based assembly system for bending-
active plate structures
Niloofar IMANIa*, Axel KÖRNERa, Riccardo LA MAGNAa, Jan KNIPPERSa
*niloofar.imani93@gmail.com
a Institute of Building Structures and Structural Design (itke), Faculty of Architecture and Urban Planning,
University of Stuttgart, Germany, Keplerstrasse 11, 70174 Stuttgart, Germany
Abstract
This paper investigates a novel assembly system that employs tension force to transform initially planar
elements into bending-active plate structures. Tension is applied through cables connecting bending-
active elements. The elements are designed through form planarization, tessellation, and stripe definition
on an input geometry. The system offers the benefit of reduced joinery sequences by having minimum
tension cables operating in both the joinery and assembly process. Moreover, since there is a correlation
between the tessellation process and the arrangement of the cables on the input geometry in the proposed
assembly system, this research followed a design-to-assembly workflow. This workflow includes a set
of digital tools and various physical tests in small and large scale. Finally, the paper discusses the
practicality of the system and further potentials.
Keywords: bending-active, assembly systems, digital fabrication, optimization, large-scale, shell structures, user-
friendly
1. Introduction
The term "bending-active" refers to curved beams and surface structures that establish their geometry
through elastic deformation of initially planar units (Lienhard et al. [7]). By utilizing active bending,
shell-like freeform structures such as the Multihalle in Mannheim can be achieved (Brütting [3]) (Fig.
1). Due to their deformation behavior and added stiffness in their bent state, bending-active structures
have attracted many engineers and designers over the years. Since bending-active structures are
produced from flat or linear elements (Lienhard et al. [7]), they offer advantages for fabrication and
transportation. Additionally, elastic deformation is an intuitive transformation mechanism that shapes
flexible elements in various geometries (Brancart [1]). Recent developments in simulation techniques
have rendered the possibility to form-find and analyze structures that achieve their complex curved
geometry solely from the elastic deformation of the planar elements (Lienhard et al. [9]). This research
contributed to the potentials of these structures by assisting from simulation techniques and
computational tools towards developing a novel assembly system.
1.1. Related works
This section introduces the relevant works that were the inspirational or technical basis for conducting
this research. These works include a form-finding simulation approach and a tessellation approach for
bending-active structures.
Proceedings of the IASS Annual Symposium 2020/21 and the 7th International Conference on Spatial Structures
Inspiring the Next Generation
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Figure 1: Multihalle Mannheim (Photo: Atelier Frei Otto Warmbronn [13]), ICD/itke research pavilion 2010
(Photo: Roland Halbe [14]), Pillars of dreams (Photo: NAARO [15])
1.1.1. Contraction cable approach
As the conceptual inspiration of this research, the contraction cable approach (Lienhard [6]) has been
abstracted and translated into the proposed assembly system. This approach was introduced and
developed as a FEM practical form-finding method of bending-active systems (Lienhard et al. [8]). This
strategy makes the elastic formation process possible by pulling the contracting cable elements
connecting the element’s anchor points (Fig. 2). By shortening the length of the virtual cables, the planar
element bends into shape.
Figure 2: Form-finding with contracting elastic cables (Schleicher et al. [11])
Figure 3: Assembly of bending-active stripes with tensioned cable
1.1.2. Form-conversion
As a digital segmentation method, this research studied approaches that enable generating developable
units. Some approaches of approximating doubly curved geometries to developable units by
strategically removing material have been explored in the works of Xing (Xing et al. [12]) as bend
decomposition and La Magna (La Magna [4]) as form-conversion. The general procedure in these
approaches consists of meshing the target surface, performing an interior offset for each face of the
Proceedings of the IASS Annual Symposium 2020/21 and the 7th International Conference on Spatial Structures
Inspiring the Next Generation
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mesh, and connecting the disjointed faces by creating a bridging element. The bridging element is
modified to consider the bending curvature (Fig. 5, (a)). The form-conversion tool is utilized for the
segmentation process in this research.
1.2. Aim and scope of the research
The presented research investigated bending-active structures' formation process and introduced a
hybrid formation approach through utilizing tension force. It developed an assembly/joinery system that
aids the possibility of erecting bending-active structures from a 2D planar state to a 3D bent state with
reduced assembly sequences. This paper explores the definition of bending-active stripes out of
tessellated free-form geometries while strategically defining the structure's assembly cables' path and
joinery placement by employing existing computational design. This research was inspired by the
contraction cable method of form-finding (Lienhard [6]) and aimed to translate and employ this digital
form-finding approach to a physical assembly approach. Similarly, the proposed assembly system
introduces tension elements that are weaved through the bending-active units as an integrated
assembly/joinery element. By shortening the length of the cables due to contraction, the planar units
bend into the desired shape and move into their place. Within this approach, joinery and assembly of
the units occur at the same time. (Fig.3)
Evaluation of the new assembly process was another topic of the research. This was achieved by defining
sets of tests and physical prototyping through case studies. For this purpose, two types and scales of
physical testing are presented. The first type evaluates the pure geometric effects on a small scale. Thus,
for an authentic evaluation of the results, these tests require a material system that excludes or minimizes
friction, self-weight, and fiber direction of the material (Fig. 9). The second type of test aims to
understand the materiality and scalability challenges that emerge on a large scale. Finally, this paper
explores the system's potentials and limitations and proposes different applications in construction and
other related fields.
2. Methodology
To develop the assembly system, this research employed and developed different types of methods.
These methods include workflow, digital methods, to computationally design and program the process
and finally, physical testing in two scales as an evaluation method.
2.1. Workflow
In this research, defining the stripes and exploring the optimal arrangement for the assembly cables are
codependent processes; therefore, defining a workflow that includes the design-to-assembly process is
essential. For this purpose, this research developed an evaluation feedback loop. Within this loop,
parameters that affect the assembly process are defined, tested, and evaluated. The workflow consists
of digital tools and physical tests (Fig. 4). The digital process is initiated with tessellation of the input
geometry and eventually leads to unrolled ready-to-fabricate stripes. Afterwards, the physical tests are
operated. The results of the tests optimize the workflow by updating the inputs for the stripe generation
algorithm.
2.2. Digital methods
Digital methods were developed computationally and are classified as stripe generation, and analysis
and form-finding.
2.2.1. Stripe generation
This research aimed to both introduce and optimize a new assembly/joinery approach. Thus, it explored
the solutions that minimize the contraction sequences and connections and eventually followed a method
to generate bending-active stripes out of multiple discrete segments (Fig. 5, (b)). As the first design step,
a global geometry must be defined. The input geometry can be designed and modified by the users in a
Proceedings of the IASS Annual Symposium 2020/21 and the 7th International Conference on Spatial Structures
Inspiring the Next Generation
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CAD environment. This research used Rhinoceros® as the CAD-3D environment. After segmentation
of the input geometry via the form-conversion tool, the stripe generation tool utilizes the resulted
segments as an input. This research developed an iterative algorithm to define stripes out of discrete
elements (Fig. 6). As there are numerous possibilities to define stripe paths from discrete elements,
specific parameters need to be defined to structure the algorithm. These parameters, algorithm logic,
and process of stripe definition will be elaborated in the development section of this paper. The overall
stripe generation process is operated in the grasshopper and grasshopper python environment.
Figure 4: Evaluation feedback loop as a workflow methodology
2.2.2. Analysis and bending behavior form-finding
The bending-active stripe's formation process was done via the Kangaroo physics2 plugin from Daniel
Piker (Piker [10]). Within this simulation, virtual cables were defined to connect two stripes in their
connection zone. This was operated by shortening the length of the virtual spring between the stripes.
For each stripe-to-stripe connection, two anchors were defined on their connection zone. From each
anchor, a cable was assigned to its corresponding anchor on the second stripe. Thus, overall, two cables
were defined on each connection zone. By contracting the two cables simultaneously, the formation
behavior was simulated. However, this process was limited to a single stripe-to-stripe connection, and
further studies on simulation of the overall system contraction process need further exploration.
For the other digital method, basic structural analysis was operated to evaluate the large-scale
prototype's stability through deformation and stress analysis in SOFiSTiK®.
Proceedings of the IASS Annual Symposium 2020/21 and the 7th International Conference on Spatial Structures
Inspiring the Next Generation
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(a)
(b)
Figure 5: (a) Segmentation process with form-conversion tool
(b) Stripe generation process from segmented geometry
2.3. Physical testing
This method evaluates the accuracy and practicality of the system through employing tests in small and
large scales. However, the small scale tests are the main topic of this research, as they produce assignable
data to employ on every free form surface.
2.3.1. Material system
The small scale material system consists of a 0.5mm monofilament fishing line as the tension element
and 0.75mm polystrol sheets as bending material. For the large scale, 1.5 mm birch plywood, 0.5mm
monofilament fishing line as the tension element, and 4mm lacing inserts for the connection zones were
used.
2.3.2. Prototypical geometries
The stripes are defined on the hemisphere and cylinder as default geometries for the small scale to
experiment with different tests, as these shapes offer regularity of geometry and defined radius and
curvature (Fig. 7(a)). The rules derived from these tests can be extended towards any doubly-curved
surface; to evaluate this, a set of prototypes on irregular geometric case studies was executed. (Fig. 7,
(b))
(a) (b)
Figure 7: (a) prototypical test geometries, (b) irregular case studies evaluation geometries
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Inspiring the Next Generation
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3. Research developments
In this section, the developments of the research are described, including assembly tests in small scale,
test results, and finally materializing the assembly system on a large scale. Before elaborating on this
section, it is essential to introduce the primary terminologies that are utilized in this research:
Stripe path (graph): Each stripe is characterized by its path and its length. Followed by the input
geometry meshing result (this research employs triangular meshing), the stripe path (graph) is defined
by connecting the centroids of selected neighboring mesh faces.
Stripe deviation: A line that connects the stripe start point to its end point defines a so-called stripe
vector. Stripe deviation illustrates the angle between the stripe vector and a vertical straight line.
Stripe length: Strip length is defined as the length of the polyline of the strip path graph. The minimum
or maximum length of the strip is defined based on the material properties, fabrication tool limits, and
transportation machine dimensions.
Figure 8: Research parameters definition illustration on mesh faces
3.1. System evaluation: small scale
To understand and evaluate the absolute effect of the following geometric parameters on the assembly
process, the following tests on the small scale are operated. The results of these test can be extended to
any doubly-curved free-from surface. Afterwards, a few experiments have been done on irregular
geometries for a better understanding of the system behaviour. (Fig. 9)
3.1.1. Benchmark test
The aim of this test is to understand the behaviour and limitation of the material system. In this test,
the maximum number of connection zones that can be joined within one contraction sequence is
measured.
3.1.2. Surface curvature effect
This parameter examines the effect of the surface’s absolute curvature on the number contracted joints.
For this tests, four stripes were defined on a hemisphere with different curvatures.
Proceedings of the IASS Annual Symposium 2020/21 and the 7th International Conference on Spatial Structures
Inspiring the Next Generation
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3.1.3. Stripe deviation effect
This parameter is observed locally and globally. This research only focused on global deviation. The
global deviation is defined as the absolute value of the angle between the stripe vector and x vector. The
aim of this test is to examine if and how this parameter has an impact on the assembly process. This test
was operated in four stripes with similar surface curvature and different deviation angles (Fig. 10)
3.1.4. Assembly order effect
The assembly order implies if the cable is pulled from its one end (one-sided assembly) or from its both
ends (two-sided assembly). This test was conducted to understand how the assembly order influences
the overall number of contracted joints.
Figure 9: Physical prototypes on irregular geometric case studies in small scale
Proceedings of the IASS Annual Symposium 2020/21 and the 7th International Conference on Spatial Structures
Inspiring the Next Generation
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Figure 10: Example of four different stripe deviations
3.2. Test results: Small scale
The following rules are attained from the test results:
a. Regardless of the surface curvature, stripe deviation, friction, and material fibre direction, a limited
number of joineries can be connected within one contraction.
b. The angle of stripe deviation has no effect on the assembly sequence.
c. As the curvature increases in the input geometry, the number of contracted joints within one
contraction decreases. This result can guide the users to define the density of the mesh in higher
curvature areas strategically (a lower mesh density leads to lower joineries).
d. Two-sided assembly doubles the number of assembled joints within one contraction. However,
depending on anchors and stripes' location, two-sided assembly is not always practical as it requires
space and defined contraction vectors.
e. The value of global stripe deviation has zero impact on the number of joint contractions. In other
words, by increasing or decreasing the strip deviation, the same maximum number of joints will be
connected. Therefore, this parameter remains uninfluential on the assembly process, while it is still
effective on the bending behaviour of the stripes in unidirectional materials.
3.3. System evaluation: Large scale
This test is set to understand and evaluate the challenges of scalability and materialization, which emerge
in the proposed tension-based assembly system's design and assembly process. The target geometry is
a 1.8m * 0.5m (height*span) vertical cantilever structural element.
3.3.1. Multi-layering
To increase the structural capacity, a layered system has been proposed. Multi-layering was performed
through offsetting the shell to create material stiffness by generating a truss-like cross-section. The
layered structure was generated by offsetting the initial mesh and adding a bending-active mid-layer
stripe connecting the two meshes. To elaborate, the mid-layer connects the bridging element in the top
and bottom layer of the form-conversion model. The offsetting distance is dependent of the maximum
Proceedings of the IASS Annual Symposium 2020/21 and the 7th International Conference on Spatial Structures
Inspiring the Next Generation
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bending radius of the elastic material. Figure below (Fig. 11) illustrates the correlation between the mid-
layer bending radius, the offset distance and initial mesh density.
3.3.2. Stripe generation logic
The strategy for the stripes was to generate them with minimum global deviation. This decision aimed
to minimize the effect of the fiber direction in plywood on the bending behavior. The stripe length was
limited to the dimensions of sheet material and CNC machine.
3.4. Test results: Large scale
The assembly process was completed successfully, and all the joints were contracted (Fig. 12). No
damages in the stripes or cables were observed. The assembly process took place in less than a day. The
main challenges emerged during the erection process of the stripes, especially in the initial assembly
sequences. One of the prominent challenges was the stripe undesired deformations. This was avoided
by using manual support to keep the stripes from excessive movements during erection. The other
difficulty emerged in regards to the cables contraction process, as no pulling direction and mechanism
were defined. Therefore, this research recommends a winch mechanism for the contraction process for
practicality and optimizing the force transfer.
Figure 11: Correlation between mid-layer bending radius (1/κ1, 1/κ2), offset distance (h) and mesh face edge
length (d)
4. Summary and reflection
This paper suggests the potentials of considering the assembly and joinery process in the early
tessellation stages of bending-active structures. In the realm of digital fabrication and parametric design,
this research employed existing tessellation methods. It developed an iterative digital tool to generate
bending-active stripes. The research's main focus was to explore the pure geometric parameters and their
impact on the assembly system. Thus, it has been conducted material unspecified; therefore, studying
material properties and precise analysis on their fiber-direction, bending stiffness, and implementing
these properties into early design needs further development.
Although this research generated individual digital scripts for stripe definition, bending-simulation, and
basic structural analysis, a comprehensive digital framework from early form-finding design iteration
to fabrication is missing. The combination of bending and tension elements and their effect on the
system's overall force flows and structural stability needs to be developed further. Since bending-active
plate structures often require strategic removal of material (Schleicher et al. [11]), multi-layering can be
seen as a relevant solution to generate architectural enclosure while creating material stiffness. This
research contributed to this topic by developing a multi-layered bending-active system that offers semi-
Proceedings of the IASS Annual Symposium 2020/21 and the 7th International Conference on Spatial Structures
Inspiring the Next Generation
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enclosure through the mid-layer and connection zones' strategic definition. Further studies on the
meshing and possibly shifting the top layer's mesh can lead to interesting enclosed results.
Finally, studies on parameters that can decrease external forces such as friction can lead to studies on
the detailed design of connection zones and strategic arrangement/placement of the contraction sources.
Figure 12: Large scale demonstrator assembly process
5. Potentials and future applications
While the proposed approach does not suggest entirely replacing the established and conventional
joinery methods (i.e. bolts and screws), it simply broadens the future applications and potentials of
employing bending-active structures in architecture, engineering, construction, and art fields.
In an ever-changing society, temporary and mobile structures are efficient solutions to adapt to abrupt,
short-term needs in a reversible way (Brancart, De Laet and De Temmermann [2]). By employing the
elastic behavior of flexible bending-active elements in the design process of transformable or deployable
structures a wide range of kinetic concepts can be achieved (Brancart [1]). Further studies on the tension
cables' impact on the stability and reinforcement of the structure and enhancing the structure's load-
bearing capacities, combined with enclosure strategies can lead to generation of user-friendly
deployable architecture, shells, or formwork. Finally, in conjunction with actuators, sensors, or motors
to initiate and automate the contraction process, together with form-finding and geometric studies the
system has the potential to be developed towards adaptive façade principles.
Acknowledgements
The research was realized as a master thesis in collaboration with Ahmad Razavi in the framework of
the Integrative Technologies and Architectural Design Research M.Sc. program (ITECH) at the
University of Stuttgart, led by the Institute of Building Structures and Structural Design (itke) and the
Institute of Computational Design and Construction (ICD).
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Inspiring the Next Generation
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References
[1] Brancart, S., De Laet, L., De Temmerman, N. (2016). Transformable bending-active structures:
manipulating elastic deformation in kinetic and rapidly assembled structures. Proceedings of the
International Conference on Structures and Architecture (ICSA).
[2] Brancart, S., De Laet, L. and De Temmerman, N. (2016). Deployable Textile Hybrid Structures:
Design and Modelling of Kinetic Membrane-restrained Bending-active Structures. Procedia
Engineering, 155, pp.195204.
[3] Brütting, J., Körner, A., Sonntag, D., Knippers. J. (2017). Bending-Active Segmented Shells.
Proceedings of the IASS Annual Symposium 2017 “Interfaces: architecture.engineering.science”
25 - 28th September, Hamburg, Germany.
[4] La Magna, R. (2017). Bending-Active Plates - Strategies for the induction of curvature through
the means of elastic bending of plate-based structures”. Ph.D. dissertation, Dept. ITKE, Univ. of
Stuttgart, Stuttgart.
[5] La Magna, R., Schleicher, S., Knippers, K. (2016). Bending-Active Plates: Form and Structure.
Advances in Architectural Geometry, 170-186.
[6] Lienhard, J. (2014). “Bending-Active Structures Form-finding strategies using elastic
deformation in static and kinetic systems and the structural potentials therein”. Ph.D. dissertation,
Dept. ITKE, Univ. of Stuttgart, Stuttgart.
[7] Lienhard, J. and Knippers, J. (2013). Considerations on the Scaling of Bending-Active
Structures. International Journal of Space Structures, 28(3-4), pp.137148.
[8] Lienhard, J. and Knippers, J. (2015). Bending-active textile hybrids. Journal of the
international association for shell and spatial strucutres, 56(1).
[9] Lienhard, J., Gengnagel, C., Knippers, J., Alpermann, J. (2013). Active Bending, A Review on
Structures where Bending is used as a Self-Formation Process. International Journal of Space
Structures, 28(2-3):187-196.
[10] Piker D. (2013). Kangaroo: form finding with computational physics, Architectural Design.
83.2, 136-137.
[11] Schleicher, S., Rastetter, A., La Magna, R., Schönbrunner, A., Haberbosch, N., Knippers, J.
(2015). Form-finding and design potentials of bendingactive plate structures. Modelling
Behaviour. Switzerland: Springer International Publishing, p. 5363.
[12] Xing, Q., Esquivel, G., Akleman, E., Chen, J. (2011). Band Decomposition of 2-Manifold
Meshes for Physical Construction of Large Structures. Proceedings of the Siggraph Conference,
Vancouver.
[13] www.baunetz.de. (n.d.). Bildergalerie zu: Frei Ottos Mannheimer Multihalle droht der Abriss /
Das Wunder soll weg - Architektur und Architekten - News / Meldungen / Nachrichten -
BauNetz.de. [online] Available at: https://www.baunetz.de/meldungen/Meldungen-
Frei_Ottos_Mannheimer_Multihalle_droht_der_Abriss_4769663.html?bild=1.
[14] Anon, (n.d.). Research Pavilion at the University of Stuttgart by ICD/ ITKE Roland Halbe.
[online] Available at: https://rolandhalbe.eu/portfolio/research-pavilion-at-the-university-of-
stuttgart-by-icd-itke/
[15] ArchDaily. (2019). Pillars of Dreams Pavilion / MARC FORNES / THEVERYMANY. [online]
Available at: https://www.archdaily.com/918398/pillars-of-dreams-pavilion-marc-fornes-
theverymany
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