The evolution of engineers’ formulation of the electrical-mechanical analogy from 1920 to 1960
Gaget, Hélène
The evolution of engineers’ formulation of the electrical-mechanical analogy from 1920 to 1960 - 2019.
50
Because of the similarity between the differential equations used in mechanics and electricity, the variables of these domains had already been set in analogical correspondence at the beginning of the twentieth century. This relationship was reinforced by the idea of a causality between force and displacement transposed onto the variables of e.m.f. and current. The goal of this article is to show how, from 1920 to 1960, engineers understood, adapted and developed this analogical relationship between different domains of engineering.By the end of World War I, some new electrical concepts and theorems made it possible to proceed without solving difficult differential equations. By analogy, the various electrical methods were transferred to the mechanical domain, allowing parallels to be drawn, not only due to the use of the same equations but also in networks equivalent to electrical circuits, notably in acoustics and electromechanics. But a difficulty arose in elaborating these equivalent networks, as their series or parallel character was inversed between the electrical and the mechanical domain. To overcome this problem, a new analogy was developed. In 1932, Floyd A. Firestone proposed a synthesis that he called the mobility analogy. This analogy linked force and current, displacement and tension, but it only seems to have come to the attention of the engineering community in 1939. The community was divided over the approach, with some engineers pointing out that, depending on which analogy they chose, it was impossible to formulate either the electromagnetic or the electrostatic coupling between systems. The elaboration of a gyrator, a new component linking force and current, around 1950 allowed each of these analogical systems to formulate the two kinds of coupling. The choice between them could then be left to the engineer’s discretion.During the 1950s, the linking of quantities extended to other domains. All the remaining problems were solved one after the other, and the various domains could be unified by the linking of their variables, enabling a discipline that could model multi-domain systems.
The evolution of engineers’ formulation of the electrical-mechanical analogy from 1920 to 1960 - 2019.
50
Because of the similarity between the differential equations used in mechanics and electricity, the variables of these domains had already been set in analogical correspondence at the beginning of the twentieth century. This relationship was reinforced by the idea of a causality between force and displacement transposed onto the variables of e.m.f. and current. The goal of this article is to show how, from 1920 to 1960, engineers understood, adapted and developed this analogical relationship between different domains of engineering.By the end of World War I, some new electrical concepts and theorems made it possible to proceed without solving difficult differential equations. By analogy, the various electrical methods were transferred to the mechanical domain, allowing parallels to be drawn, not only due to the use of the same equations but also in networks equivalent to electrical circuits, notably in acoustics and electromechanics. But a difficulty arose in elaborating these equivalent networks, as their series or parallel character was inversed between the electrical and the mechanical domain. To overcome this problem, a new analogy was developed. In 1932, Floyd A. Firestone proposed a synthesis that he called the mobility analogy. This analogy linked force and current, displacement and tension, but it only seems to have come to the attention of the engineering community in 1939. The community was divided over the approach, with some engineers pointing out that, depending on which analogy they chose, it was impossible to formulate either the electromagnetic or the electrostatic coupling between systems. The elaboration of a gyrator, a new component linking force and current, around 1950 allowed each of these analogical systems to formulate the two kinds of coupling. The choice between them could then be left to the engineer’s discretion.During the 1950s, the linking of quantities extended to other domains. All the remaining problems were solved one after the other, and the various domains could be unified by the linking of their variables, enabling a discipline that could model multi-domain systems.
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