Authors: George I N Rozvany
Publish Date: 2010/09/14
Volume: 43, Issue: 3, Pages: 297-317
Abstract
The aim of this article is to initiate an exchange of ideas on symmetry and nonuniqueness in topology optimization These concepts are discussed in the context of 2D trusses and grillages but could be extended to other structures and design constraints including 3D problems and numerical solutions The treatment of the subject is pitched at the background of engineering researchers and principles of mechanics are given preference to those of pure mathematics The author hopes to provide some new insights into fundamental properties of exact optimal topologies Combining elements of the optimal layout theory of Prager and the author with those of linear programming it is concluded that for the considered problems the optimal topology is in general unique and symmetric if the loads domain boundaries and supports are symmetric However in some special cases the number of optimal solutions may be infinite and some of these may be nonsymmetric The deeper reasons for the above findings are explained in the light of the above layout theoryThe author is grateful to Martin Bendsoe Rafi Haftka Ming Zhou Tomasz Lewinski and Tomasz Sokol for discussing some relevant aspects of topology optimization Special thanks are due to the reviewers of this article for many useful suggestions including the proof of Conjectures 2 and 3 Financial support from OTKA Grant No K 81185 is thankfully acknowledgedSince the number of variables in this formulation is 2m for any basic solution we need 2m equality constraints eg Strang 1980 Chapter 8 some of which were originally inequalities Let the number of static equations be r and the number of zero member forces k
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