NUMERICAL EXPERIMENTS ON DYNAMIC STIFFENING OF BEAMS AND PLATES

By introducing continuous or discontinuous variations in the thickness of beams, arches and plates, it is possible in many practical situati ons to raise the value of the fundamental frequency and, at the same t ime, to lower the weight of the structural element. This is a benefici al situation, especially in those cases where weight reduction and lar ge dynamic stiffness are of interest. The present paper surveys some r ecent practical accomplishments in this area. The rigorous procedure c onsists, from a general structural optimization viewpoint, of minimizi ng an objective function (for instance, total volume) subject to const raints on the geometry and behavior (natural frequencies, buckling loa ds, etc.). In many instances it is convenient to reverse the problem: one fixes or limits the weight or volume and constructs some quantity which describes the desired behavior of the system e.g. the fundamenta l frequency. The problems under study in the present paper are conside rably more modest in scope, since the procedure is performed by numeri cal experiments. (C) 1997 Elsevier Science Ltd.