Static Resilience of Large Flexible Engineering Systems: Part II–Axiomatic Design Measures

Our modern life has grown to depend on many and nearly ubiquitous large complex engineering systems. In recent years, many disciplines have seemingly come to ask the same question: “In the face of assumed disruption, to what degree will these systems continue to perform and when will they be able to bounce back to normal operation”. This paper seeks to partially fulfill this need with static resilience measures for large flexible engineering systems based upon an axiomatic design model. Given that the measurement of resilience is an indirect measurement process based upon models and formulaic measures, this two part paper is similarly organized. In Part I, the model is developed upon graph theory, axiomatic design for large flexible engineering systems (LFESs), and a tight analogy between mechanical systems and LFESs. Central to the development is the concept of structural degrees of freedom as the available combinations of systems processes and resources which individually describe system capabilities or sequentially give a sense of the skeleton of a system’s behavior. In Part II, the structural degree of freedom model is used to enumerate the service paths through a LFES along which valuable artifacts flow. The work then compares the value and quantity of service paths before and after a disruption as measures of static resilience – or survivability. A full illustrative example from the production system domain is provided. It is followed by a thorough discussion of the proposed resilience measures relative to the recent literature.