Structural mechanics analogies for a resilience audit and index

Abstract

The World Economic Forum’s (WEF) Global Risks Report 2013 arrived at a working definition for national resilience that involved three characteristics, namely robustness, redundancy and resourcefulness. We have drawn mappings between the WEF’s robustness, resilience and resourcefulness and the structural engineering characteristics of robustness, redundancy and ductility. We use this first to propose a multi-sectoral framework involving the infrastructural, environmental, sociological, economic, and geopolitical sectors, also proposed by the WEF, but divide them into the three hierarchical levels of country, city and building. These three levels, three characteristics and five sectors give rise to a matrix of 45 aspects, with resilience features suggested for some of them. In this way we move towards proposing a multisectoral, multi-hierarchical resilience audit for a nation. We then use force-displacement analogies from structural mechanics to quantify resilience through an analogy to energy absorption, depending on the various levels of robustness, redundancy and ductility, thus generating an 8-point scale for a resilience index. The analogy suggests that ductility is the most important characteristic, but that it can be traded-off with redundancy. Redundancy is more important than robustness, but both are much more important for systems that lack ductility compared to those that possess it.