Characteristic values of materials determined in experiments
Parametric control with Grasshopper 2D polylines structural analysis pre-model
2D polylines fabrication model
3D surface- design model
Simulation model analysis mesh model Sofistik Finite element model (FEM)
Robotic production Hypermill determining milling paths Robomove robot control
Surveying model positioning on site Leica Cyclone Leica CloudWorx Leica TruView
Pavilion after completion of assembly Comparison of computer models with measurements of actual state
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führenden Schritte: die statische Berech nung durch »Aufwickeln« der ebenen Strei fen mittels FEM-Analyse (Abb. 4), die robo tische Fertigung und die exakte Positionie rung auf dem Gelände. Während für einen Durchlauf des Informationsmodells nur weni ge Minuten erforderlich sind, benötigt ein leistungsfähiger Computer für das FEM- Modell eineinhalb Tage reine Rechenzeit! Schließlich können die Wissenschaftler am gebauten Pavillon anhand von Belastungs tests das Relaxationsverhalten, d. h. das alterungsbedingte Nachlassen der Eigen spannung von Sperrholz messen, um die Werte in künftige virtuelle 3D-Modelle einflie ßen zu lassen (Abb. 5). DETAIL 10/2010
At the end of the summer semester in 2010, a vaulting temporary research pavilion was built at the edge of the Stuttgart University campus. The starting point for this student scheme was the unexploited structural potential of plywood. The geometry is based on linked pairs of segmental arches (ill. 2), 40 of which (i.e. 80 radial strips) were needed to close a torus with an external diameter of 10 m. With a span of 3.5 m, this filigree structure is both efficient and stable (ill. 1). The faculty’s own industrial robot, configured as a CNC milling machine, was used to give each of the more than 500 timber elements its own geometry. The 10-metre plywood strips also had to be cut into segments for transport (ill. 3). The individual segments
are subject to either tensile or bending stresses, whereby each tensile segment elastically maintains the form of the adjoining bending segment (ill. 2). The entire pavilion was constructed from birch-plywood strips only 6.5 mm thick. The digital information model was based on the bending behaviour (ill. 1) and a script with roughly 6,500 lines of code. This forms the basis of all further steps: the structural calculations in a process of “coiling up” the flat strips by finite element analysis (FEA) (ill. 4); and the robotic production of the elements and their positioning on site. The relaxation behaviour of the finished pavilion as a result of ageing can be measured and the results used as data input for future virtual 3D models (ill. 5).
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