Scanning in 3D and analysing the models of Heinz Isler, the preliminary results

During his live Heinz Isler built around 1400 shell structures, until he deceased in 2009. Heinz Isler is part of a Swizz tradition of structural art in the 20th century, which includes engineers such as Robert Maillart, Othmar Ammann und Christian Menn [1]. During his live Heinz Isler developed several methods for physical form finding of his shell structures [2, 3]. Methods such as hanging models, inflated membranes etc. The physical scale model where used for determining the strains and stresses in the shell structure. This was done by loading the scale models and measuring the strains and consequently calculating the stresses. The geometry of the scale models was used for the actually build shell structures by precisely measuring the scale models and scaling these up to the real size shell. Analysing Isler’s shells has always been impossible because Isler never published the precise geometry of his shell structures. Isler’s model where scanned for the first time ever in 2011, the results where used to construct NURBS (Non Uniform Rational B-spline) surfaces which describe the exact geometry of Isler’s scale models. The results are used for all kinds of analysis, such as finite element (FEM) calculations, curvature analysis etc. This means that for the first time a qualitative investigation can be made of Isler’s shell structures. This paper will present the first results. Hopefully it will give us a greater insight in the relation between geometry and the structural behaviour of shell structures.