A Computational Tool for the Design of Prestressed Cable Supported Structures
Typ
Examensarbete för masterexamen
Program
Structural engineering and building technology (MPSEB), MSc
Publicerad
2020
Författare
Abdul Sater, Ahmad
Thor, Oskar
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Abstract
Cable supported structures are light-weight structures gaining their load-bearing
capacity through the use of one or several cables in combination with other structural
members such as struts, beams, and plates. Cables transfer loads in tension only
and adapt their shape depending on the loading condition. The relationship between
applied loads and deformations is therefore highly non-linear and consequently the
geometrical shape of cables requires bespoke design approaches.
Traditionally, architects and engineers have designed cable structures using physical
models or with graphical methods. This has changed as advances in numerical
analysis and computational engineering have been made over the recent century.
Many software programs available today can be used for analysis. However, a key
part of structural design requires the ability to "sketch" and "iterate", which is absent
in many available packages.
A computational design tool is developed with the aim to support the design in
early design stages. After evaluating three existing numerical methods for large
displacement structures, a solver with Green strain bar elements is implemented.
The tool extends the open-source BHoM code library. Output data from the tool is
benchmarked by comparing results with analytical and numerical models.
By exposing the functionality of the tool to user-interfaces such as Grasshopper and
Excel, users can explore alternative design proposals by changing a set of parameters.
These parameters include the input geometry, initial prestress, section sizes and
topology.
Case-studies are used to highlight how this tool is used in Grasshopper. A set
of design-objectives are defined and met by controlling a set of parameters, subsequently
creating several designs proposals. For the studied cases, which display small
strains and large displacements, the tool provides accurate results. Should a different
analysis model be required, the tool is suited for modifications and extensions
of its capabilities.
Beskrivning
Ämne/nyckelord
cable-supported structures , form-finding , prestress , geometrical stiffness , structural design. , parametric design