A computational study on a nature inspired novel doubly curved folded shell structural form
Loading...
Date
2007
Authors
Abdulrazzack, Suhail Abdulaziz
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
In this research, the leaves of Johannesteijsmannia altifrons (J. altifrons) which belong
to the palm family have been investigated. These leaves are doubly curved cantilever
shell structures with folds extending from the central spine. The target of the study is in
two folds: to investigate the influence of shape and folds on the structural behaviour of
the J. altifrons and to investigate the structural behaviour of the J. altifrons like scaledup,
realistic models under practical considerations using finite element analysis. A noncontact
method called structured lighting method has been used for capturing the
surface data of the leaf. An algorithm based on the actual geometry of the imaging
setup has been developed and used in this study. The leaves have been analysed
using orthotropic material properties of eleven species of wood. The results show
efficient structural performance of the leaves in terms of stiffness and strength. In order
to study the influence of the folds on structural behaviour, non-folded versions have
also been generated and analysed. Folded models showed better performance in
terms of stiffness and strength compared to the non-folded versions. The synclastic
and anticlastic folded models yielded maximum deflection values of about 70% and
30% of the values in the corresponding flattened models, respectively. Similar
comparison in terms of stresses yielded values of about 40% and 20% of the
corresponding stresses in flattened models for both tension and compression. In view
of the biomimetic nature of the study, a simple method called Source Referenced
Classification (SRC) to classify nature inspired technological achievements is also
presented. Novel CAD based procedures have also been developed for the purpose of
generating doubly curved surfaces with folds. These procedures have been
implemented to generate leaf-like scaled-up models. A computational study is carried
out on these models to evaluate their structural performance under self weight
condition, using light weight concrete. The results show satisfactory performance in
terms of stiffness and strength with considerable reserve in material capacity
particularly in compression (about 88%). All 6 models showed maximum deflection
values of less than 15 mm over cantilever spans of about 10 m.
Description
PhD
Keywords
Civil Engineering , Computational , Folded shell