SPECIFYING NODES AT MULTIPLE LOCATIONS FOR ANY NORMAL MODE OF A LINEAR ELASTIC STRUCTURE

Spring–mass oscillators have long been used as vibration absorbers to quench excess vibration in structural systems. In this paper, sprung masses are used as a passive means of inducing multiple nodes for any normal mode of an arbitrarily supported, linear elastic structure. When the parameters of the elastically mounted masses are properly chosen, their attachment locations can be made to coincide exactly with the nodes of the structure, thereby allowing nodes to be imposed at multiple locations anywhere along the combined assembly. Moreover, when the desired node locations are closely spaced, it is possible to specify a region of nearly zero amplitudes for a particular normal mode. A procedure to guide the proper selection of the spring–mass parameters in order to induce multiple nodes is outlined in detail, and numerical experiments are performed to verify the utility of the proposed scheme of imposing nodes at multiple locations.