Linear bending of star-like pyramids

A family of polyhedra possessing unusual deformation properties is found. On one hand, models of these polyhedra admit free continuous large reversible bending without visible distortions of the material. On the other hand, the polyhedra themselves are rigid and do not admit continuous bending in the sense of the Cauchy definition. The found polyhedra are called model flexors in order to distiguish them from theoretical flexsors of Connelly. Bendings of the models are asymptotically exactly approximated by linear bendings of polyhedra. They represent a nonrigid, soft or slow, loss of stability that corresponds to the loss of stability in small accordingly to Euler. This new phenomenon in mechanics of deformable solid bodies may be considered as an original geometric machine of catastrophe. To cite this article: A.D. Milka, C. R. Mecanique 331 (2003).