Bio-inspired, Flexible Structures and Materials - Biotechnologies and Biomimetics for Civil Engineering - page 287

12.4.2.1 Form-Finding and Construction
The system and geometry was developed by students from the University of
Stuttgart through a long process of physical model building, which was later
optimised through digital simulation. Aim of this process was to break free from
traded structural typologies in the search for novel formal and functional possi-
bilities in highly integrated structural systems. This process was accompanied by
the consideration of natural construction principles as introduced above.
For generative studies, the spring-based modelling environment SpringFrom
(Ahlquist et al. 2014 ) was utilised alongside exhaustive physical form-finding
experiments. The computational modelling allowed for complex topologies to be
developed and altered, quickly registering feedback from the prototypical physical
studies. This approach was utilised for the form-finding of the secondary textile
hybrid system, in particular; a series of differentiated cells providing additional
structure to the primary envelope and variation to the illumination qualities of the
space (Fig. 12.10 ). As both a design avenue and method for material specification,
FEM was utilised. Here the parameters of the complex equilibrium system were
explored to determine the exact geometry and evaluate the structural viability.
Custom programmed methods inside the general purpose FE-Software Sofistik
allowed for great degrees of displacement to be calculated in order to form-find the
beam positions. The beams were initialised as straight elements and gradually
deformed into interconnected curved geometries, finally being reshaped by the
inclusion of pre-stressed membrane surfaces (Fig. 12.9 , right). The geometric data
therein was determined initially by the physical form-finding models in defining
the lengths and association points on the rods for the topology of FE beam ele-
ments (Fig. 12.9 , left). Given the unrolled geometry and connection points of the
rods it was possible to simulate the erection process and thereby the residual stress
in a finite element based form-finding process (Fig. 12.11 ).
12.4.2.2 Biomimetic Approach
For the M1 project the aspect of Biomimetics is not used to look for a biological
role model to find a technical solution, but define a set of strategies that influenced
the entire design process. The key construction principles that influenced the
design process of the M1 were:
Anisotropy: Textile materials where used on all scales; their anisotropy was
used as a driving force in the design and form-finding process of the material
system. For the bending rods made of pultruded GFRPs this meant that maximum
material strength could be accessed, as fibres ran in the main stress direction. On a
detailed level the connection points needed reinforcement by laminating fibres in
the circumferential direction of the rods.
Heterogeneity: An important feature in the design was the structural integration
and heterogeneity, leaving the limits of strictly categorised building structures by
accumulating different load bearing strategies in an associative system. The M1