Isogeometric analysis and form finding
Typ
Examensarbete för masterexamen
Program
Structural engineering and building technology (MPSEB), MSc
Publicerad
2020
Författare
Hilmersson, Joel
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Recent developments within the design of shells have seen an increased interest in utilizing active bending
as form giving procedure [1]. This enables complex structures to be built from simple off-the-shelf
materials. However, forming bending-active structures is highly dependent on the material properties,
which makes the design process reliant on either physical testing or digital simulations. An associated
problem with the simulation of this behavior is the lack of integration between modeling and analysis in
conventional simulation techniques, a crucial concern since the final design is always an equilibrium shape
with requirements on both structural and spatial integrity. IsoGeometric Analysis (IGA) is a method
that aims to bridge precisely that gap between analysis and design, making it a suitable method for
bending active structural design.
This thesis explores an approach to the modeling and digital design of actively bent shells using the
implementation of nonlinear IGA. Further on, two different ways of controlling the geometry, either by
following the process forward and predicting the outcome or tracing it backwards during the construction
procedure are proposed. Following the process forwards returns an implicitly controlled shell geometry
through stepwise displacement of the boundaries of a flat sheet. However, as a design approach, one
appealing strategy is to explicitly control the final geometry by a backwards tracing. This allows the
designer to start from a desired outcome and instead tailor the stiffness to approximate this desired
form. The procedure is tested in a case study where a combination of both forward prediction and
backwards tracing is included. Both processes apply the Kirchhoff-Love shell theory [27] and uses the
total Lagrangian formulation for the nonlinear computations
Beskrivning
Ämne/nyckelord
Isogeometric analysis , Shell Design , Bending Active , Nonlinear , Form Finding