On the origins and development of mobility and impedance methods in structural dynamics

An account of the conception and early development of mobility and impedance methods in structural dynamics is presented in this paper. As often happens in science, the concepts and ideas developed in one branch of science have inspired new approaches and theories in another branch, and indeed this was the case for mechanical mobility and impedance, which has its origin in the field of electricity. The conception and formulation of both direct and inverse electromechanical analogies are described in this paper together with the formulation of ad hoc impedance and mobility methods that were developed for mechanical systems. Finally the impedance, mobility and transmission matrix methods that evolved for flexible, distributed mechanical systems are discussed. This paper has been written with reference to a large number of published papers many of which have been listed in the reference section.