Flexible Stiffness – Why Engineers like Oxymora so much

Sep 07, 2016

An oxymoron connects two contradictory terms. In the field of engineering this often means that the seemingly impossible has become possible. The same holds true for “flexible stiffness”. Learn what it is all about and let us know your personal favorite oxymoron.


 There is often confusion in using oxymoron and paradox. Latter term might seem contradictory at first glance, but carries a deeper meaning – as shown in the picture above.

In everyday life, we often come across oxymora, i.e. two words that contradict each other. Some of them amuse us, and others are part of our everyday speech as a matter of course, like virtual reality, free trade, original copy, old news, act naturally, pretty ugly, living dead, jumbo shrimp, rolling stop, constant variable, exact estimate, paid volunteers, sound of silence, clever fool, only choice.

Engineers also encounter contradictory word compositions during their work, for example: linear curve, constant variable, customized mass production as well as flexible stiffness. In engineering, many oxymora signify a technical or mathematical breakthrough. The impossible has become possible.

There is often confusion in using oxymoron and paradox. Latter term might seem contradictory
at first glance, but carries a deeper meaning – as shown in the picture above.The stiffness of a coupling has not been adjustable for long, or only to a limited extent. To allow at least minimum variations, engineers have so far banked on different materials. This is also what developers of a new highly flexible shaft coupling did. In addition, they adopted the principle of buffers arranged in rows. An individually adjustable coupling with variable elastomer buffers arranged in rows is the result – and the source of our favorite oxymoron.

The perfect oxymoron resulting from the Finite Element Method and Prototyping

It goes without saying that the solution to a problem that had existed for a long time does not succeed in next to no time. To develop a reliable solution in terms of flexible stiffness, the developers used the finite element method – and checked their calculations in numerous experimental runs. Thanks to the collected results, the stress and deformation of each individual buffer in every material combination can be calculated. The flexible adjustment of the stiffness is possible by the smart selection of the buffers, and thus different hardnesses. The oxymoron has been transformed to reality.

Since we had so much fun listing the examples of oxymora, we want the adventure to continue: Please send us your favorite pair of words with the reference “Oxymoron” to smarter@ringfeder.com. The most outstanding highlights will then be published on our blog in October.


Oxymoron - derived from Greek: oxýmōron, composed of oxys “sharp, keen, pointed” and moros “dull, stupid, foolish”; the plural is oxymora. A term or figure of speech that is composed of two contradictory or controversial words. According to the Greek translation, the word itself is an example of an oxymoron “sharp dullness”. 

Finite Element Method (FEM) - When creating an FEM model, constitutive equations are used to simulate the reality. This poses particular challenges as far as the new coupling is concerned, because unlike steel, plastics do not have a linear behavior. For this reason, the calculation logarithms had to be carefully adapted, too.

Prototyping - A prototype is an early version of a product or system. Prototyping is an iterative process in which prototypes are developed, evaluated and improved upon until the final product is actualized. 

White paper: A big fun on a playground swing but potentially a disaster for designengineers: Resonance.

Sophie Keil

Written by Sophie Keil

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