Optimization-based stability analysis of structures under unilateral constraints

This paper discusses an optimization-based technique for determining the stability of a given equilibrium point of the unilaterally constrained structural system, which is subjected to the static load. We deal with the three problems in mechanics sharing the common mathematical properties: (i) structures containing nocompression cables; (ii) frictionless contacts; and (iii) elastic–plastic trusses with non-negative hardening. It is shown that the stability of a given equilibrium point of these structures can be determined by solving a maximization problem of a convex function over a convex set. On the basis of the difference of convex functions optimization, we propose an algorithm to solve the stability determination problem, at each iteration of which a second-order cone programming problem is to be solved. The problems presented are solved for various structures to determine the stability of given equilibrium points. Copyright q 2008 John Wiley & Sons, Ltd.