Optimization of Cold-formed Steel Sections using Genetic Algorithm
Typ
Examensarbete för masterexamen
Program
Publicerad
2022
Författare
Aref, Sara
Mahdi, Mahdi
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Most research done on optimization of cold-formed steel members focuses on a single
cross-section with set conditions and steel yield strengths. How would this optimiza tion look if different cold-formed cross-sections are compared. Furthermore, how would different cold-formed cross-sections with varying steel yield strength behave in a global optimization.
The aim is to study how to reach optimized cross-sections (profiles) for roof trusses
in different steel strength classes using a genetic algorithm and create a library of
the most optimized cross-sections for certain spans and applied loads.
The four selected cross-sections to be analysed are C-section, double back-to-back
C-section, hollow square-section and hollow hexagon-section. These profiles can act
as diagonals in a roof truss and the compressed diagonals will be analysed. As for
the upper chord which is subjected to both compression and bending, only double back-to-back C-sections will be optimized. Matlab functions were generated to calculate the required parameters, buckling modes and capacities for the selected sections. These functions were connected to a genetic algorithm to find the most op timized dimensions for each section. Lastly the most optimized cross-sections with
respect to smallest area were selected for different load and span length combination to create a library.
The results of the genetic algorithm showed that for the upper chord the higher
the steel strength the smaller the area becomes but the section with higher steel
strength have a lower utilization ratio. The diagonals which were divided into two
groups and were analysed separately showed that the most optimized shape to use
is a hollow square-section. However, the connection between the upper chord and
the diagonals will not be feasible with closed cross-sections used as diagonals. The
chosen cross-section shape is therefore C-section.
Beskrivning
Ämne/nyckelord
steel, cold-formed, cross-section, optimization, genetic algorithm, roof truss, Eurocode 3