Some Peculiarities of the Redundant Design Solutions

Abstract

In common speech, the term redundant is used to label superfluous repetitions that as a rule should be avoided. Nevertheless, redundancy is a linguistic tool that can play a remarkable role in the communication of complex thoughts in both the vernacular and the erudite talking or writing, which includes the field of engineering design. In the Axiomatic Design (AD) point of view, redundancy may increase the complexity of the design solutions (which is measured through their information content), but does not necessarily entail the breach of the ADs independence axiom. Hence, redundant solutions should not be excluded in a regular basis, since the ones that comply with the independence axiom are considered good design. According to this line of reasoning, the pertinence of redundant solutions should be assessed in the onset of the designing processes, bearing in mind the virtues of the likely higher simplicity of the non-redundant solutions. This paper deals with some basic concepts related to redundant design and it should be seen as a contribution to bring more insight on a subject that is not thoroughly reviewed in the known literature. Different forms of redundancy are considered, specifically the reliability motivated active and passive types, and the functionality-related alternative and augmentative kinds. The means to perceive intrinsic redundancy through the examination of the design equations are also provided, as well as some illustrative examples. The implicit conclusions are that redundant designs are much more usual that one can think at a first glance, and that the study of their peculiarities might deserve further attention.