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Civil-Comp Proceedings
ISSN 1759-3433 CCP: 75
PROCEEDINGS OF THE SIXTH INTERNATIONAL CONFERENCE ON COMPUTATIONAL STRUCTURES TECHNOLOGY Edited by: B.H.V. Topping and Z. Bittnar
Paper 91
Optimal Design of Tensile Fabric Structures T. Nouri-Baranger+ and P. Trompette*
+Universite Claude Bernard-Lyon 1, Villeurbanne, France
Full Bibliographic Reference for this paper
T. Nouri-Baranger, P. Trompette, "Optimal Design of Tensile Fabric Structures", in B.H.V. Topping, Z. Bittnar, (Editors), "Proceedings of the Sixth International Conference on Computational Structures Technology", Civil-Comp Press, Stirlingshire, UK, Paper 91, 2002. doi:10.4203/ccp.75.91
Keywords: fabric, cable, tension, form finding, sensitivity analysis, optimisation.
Summary
The final design of a tensile membrane is achieved when the stress
states generated by different and normalised climatic (snow,
wind…) loadings have been deemed as acceptable by the official
control bodies. For this reason, and since in tensile structures
the shape and the stress states are strongly related, the whole
design may result from a repeated iterative process between the
designers, i.e. the firm of architects and the research
consultants. This motivates the presentation in this paper of an
optimisation tool devoted to fabric structures which could be used
to ease the design process in decreasing the number of
back-and-forth interactions between all the different
participants. First a specific and new shape form finding
procedure is proposed; taking into account the usual geometrical
constraints or data requirements, but also a desired biaxial (warp
and weft) non uniform stress state, an
![]() In the design of a tensile fabric structure the first step is called shape finding. The usual data given, by the architect are the coordinate list of several fixed points : the mast position(s) and the anchorage points. One other main data set is the tension values of all the boarder or intermediate cables and the warp and weft tensile optimal stresses in the fabric. From these data an equilibrium position is found by solving the non linear matrix equations. ![]() ![]() ![]()
Any initial geometry of the membrane may be chosen but a
As soon as the initial shape is determined a non linear finite
element analysis of the structure is performed using cable and
orthotropic membrane elements to evaluate the stresses and the
shape of the loaded structure. From this analysis, it may be
necessary to modify the initial shape if over or under stressed
parts which generate wrinkles or pockets are found. In order to
ease the designer work, a sensitivity analysis of this equilibrium
position may be performed; the design variables are: the tensions
in the cables and the positions of the anchorage points. Two
objective functions have been defined: one is concerned with the
nodal displacements to minimise their total norm and the second
with the stresses to maximise the minimum stress areas and to
minimise the maximum stress areas. The application of this
optimisation procedure yields a definition of an optimal
When the three dimensional shape is defined there remains to
define the cutting patterns. The flattening process uses a
specific method. To take into account the desired stress state in
the three dimensional fabric i.e. to correct the patterns
obtained, an iterative stress calculation process between the
The example presented in this paper is a swimming pool roofing.
The covered surface has the dimensions: References
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