From Shape to Shell

From shape to shell: a design tool to materialize freeform shapes using

gridshell structures.

Lionel du PelouxUR Navier, Ecole des Ponts ParisTech, Champs-sur-Marne, FranceT/E/S/S, Paris, FranceDr. Olivier BaverelUR Navier, Ecole des Ponts ParisTech, Champs-sur-Marne, FranceENSAG, Grenoble, FrancePr. Jean-François CaronUR Navier, Ecole des Ponts ParisTech, Champs-sur-Marne, FranceAl. Frederic TayebUR Navier, Ecole des Ponts ParisTech, Champs-sur-Marne, France

• Frei Otto et al., 1974, IL10 Gitterschalen

• Pinned connection between continuous bars

=> No shear rigididy during the erection;

• Bracing with a third direction of bar in order to get a shell behaviour

What is a gridshell?

3

Textile membrane

Grid Shell in GFRP in 2011

Design Process

3D Modeling

Wireframe geometry NURBS patch.

Shape Optimization

𝜎=𝜎𝑐𝑜𝑚𝑝+𝜎 𝑏𝑒𝑛𝑑≅ 𝜎𝑏𝑒𝑛𝑑=𝑀𝐼 /𝑣

=𝐸 .𝑣

𝑅𝑐𝑢𝑟𝑣𝑎𝑡𝑢𝑟𝑒Geometric curvature minimization in three steps. Rmin [blue = 3,00m ; red = ∈10,00m].

Shape Meshing

Shape Meshing

the gridshell surface

Shape Meshing

Shape Meshing

Shape Meshing

Shape Meshing

• Different sets of guide-curves are chosen and the resulting meshes are compared according to this criterion:

Mesh testing

Developed surface

Structural Analysis

Construction

CONCLUSION

This paper has presented the different steps for the design of a gridshell in GFRP built for the Solidays festival in 2011 in Paris.

The steps were:• the optimization of the shape in order to avoid

concentrations of curvature locally. • Automatically mesh a surface using the compass method.• Optimum orientation of the mesh.• Mesh relaxation.• structural analysis of the gridshell.

ACKNOWLEDGEMENTS

The authors would like to thank:• the students of the école des ponts (E. Roux, E. Blache, J.-R.

Nguyen, A. Grandi, G. Frambourt, T. Perarnaun), • their university supervisor (R. Mège) • The association Solidarité Sida, • The consultant T/E/S/S • The constructor Viry • Partners such as: Serge Ferrari, Top Glass & Solutions

Composites, Owens Corning Reinforcement, DSM Resins, ENSG, Esmery Caron, Axmann, Chastagner and ¨Paris Voile.

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