Code_Aster: a circus performer

by Jean-Pierre Aubry, La Machine

Instead of working on civil engineering, aeronautics or research on fatigue, here is an original structure for a change. The circus tent structure is original as regards its size: a ground area of 65’x59’ and 19’ high (20x18x6 m).

Like every circus tent structure it is made up of an outer canvas supported by stakes, poles and stays. The resistance of this kind of building to different climates, snow and wind is subjected to specific regulations.

Contrary to civil engineering structures - which are composed of stretched canvas - the prestresses on the canvas are very low or null. The poles and stakes are modelized by beam elements, stays are modelized by cable elements and the canvas by an orthogonal network of cable elements placed every 15" (in the absence of a 2D membrane element in Aster). The prestress of the putting up is obtained by "cooling down" the concerned elements while trying to minimize the prestress after some "tests and errors" in manual mode. Then the 6 loading cases are successively applied - back to 0 between every case - in a single NON LINEar STATic computation (STAT_NON_LINE) which includes 35 steps, and with the LINEar Research option (RECH_LINEAIRE). The solution can be obtained approximately after 10 minutes and 300 iterations, on a machine equipped with a 3.2 Ghz Pentium 4 which dates from 2004.

Apart from this precise example Code_Aster, Salome-Meca and Gmsh are also used by the firm La Machine in order to size or justify the sizing of the entertainment machines designed in its workshops.

Realizations of La Machine: (click on the image to enlarge)

For more information you can visit www.lamachine.fr

Contact : jeanpierre@lamachine.fr