DANGERS OF STRUCTURAL OPTIMIZATION

Abstract

This paper examines the thesis that a process of structural optimization leads inevitably to designs which exhibit the notorious failure characteristics often associated with the buckling of thin elastic shells. This means that an idealized perfect structure exhibits an unstable and often compound branching point and would fail by an explosive instability while nominally perfect real structures containing inevitable small imperfections fail at scattered loads which can be quite considerably lower than that of the idealization. It is shown via a fairly wide spectrum of examples that an increasing degree of optimization is likely to lead in turn to an unstable bifurcation, a very unstable bifurcation, and finally a very unstable compound bifurcation with the possible added danger of an unsuspected nonlinear coupling action.