
Journal of Convex Analysis 22 (2015), No. 2, 303338 Copyright Heldermann Verlag 2015 Concentration Phenomena in the Optimal Design of Thin Rods Ilaria Lucardesi Laboratoire IMATH, Université du Sud ToulonVar, Avenue de l'Université, 83957 La Garde, France We analyze the concentration phenomena which occur in thin rods, solving the following optimization problem: a given fraction of elastic material must be distributed into a cylindrical design region with infinitesimal cross section in an optimal way, so that it maximizes the resistance to a given external load. For small volume fractions, the optimal configuration of material is described by a measure which concentrates on 2rectifiable sets. For some choices of the external charging, the concentration phenomena turn out to be related to some new variants of the Cheeger problem of the cross section of the rod. The same study has already been carried out recently in the particular case of pure torsion regime by G. Bouchitté, I. Fragalà, I. Lucardesi and P. Seppecher ["Optimal thin torsion rods and Cheeger sets", SIAM J. Math. Anal. 44 (2012) 483512]. Here we extend those results by enlarging the class of admissible loads. Keywords: Thin rods, optimization, compliance, duality, dimension reduction, Cheeger problem, generalized Cheeger sets. MSC: 74K10, 49J35, 49Q10, 28A25 [ Fulltextpdf (285 KB)] for subscribers only. 