Professor Benoît Iung

Professor Benoît Iung


Advanced Maintenance Services for Promoting Sustainability
Benoît Iung and Eric Levrat
Lorraine University, CRAN, CNRS UMR 7039, Nancy, France


Abstract
In modern manufacturing processes, opportunities to increase efficiency still exist, but the gains are largely incremental and insufficient to generate real competitive advantage or differentiation. In that way, some business leaders are moving towards an industrial model that decouples revenues from material input by promoting actually sustainability and then the circular economy (in opposition as linear economy) [1]. The circular economy is a generic term promoted by foundation such as Ellen McArthur for an economy that is regenerative by design. It means that the conventional entire life cycle product phases (Beginning-of-Live BOL, Middle-of-Life MOL, End-of-Life EOL) has to be reconsidered for replacing the EOL with restoration, shift towards the use of renewable energy, eliminates the use of toxic chemicals, (return to the bio-sphere), and aims for the elimination of waste. In that way, the maximum value could be extracted from restoration and recycling (less energy and cost efficient than producing everything from scratch reused multiple times) [2].
Thus, circular economy is an extension of industrial ecology concept [3], circular manufacturing concept [4], sustainable manufacturing [5] to favor remanufacturing [6] popularly known as “reman” and for which emergent through-life engineering services have to be addressed to support new requirements related to these innovative concepts. It is based on the principle assuming that sustainability is achieved thanks to the cyclical nature of eco-systems. It leads to rethink how the industrial systems must be designed in order to establish not only interactions between these systems but also with the natural environment.
This principle is referred to the paradigm named regeneration [2] supporting the evolution from eco-efficiency consideration to eco-effectiveness one. Indeed the regeneration paradigm is showing the interacting notions of bio-sphere (“natural” sphere) and techno-sphere (“technical” sphere). Natural industrial resources (materials) can go back to the bio-sphere without disturbances if they are not degraded, and technical resources (materials) must remain as long as possible in the techno-sphere in order to limit the consumption of raw materials, wastes, emissions …
To face with these paradigms of regeneration and circular economy, the maintenance (with repair and overhaul, MRO) is a major service to be considered. Indeed Maintenance is contributing, as enabling system, to sustain the target system all along its life cycle (general point of view on the system) but also maintenance is a key tool to keep the regeneration potential (by means of maintenance actions) of system components (field level point of view) within the target of sustainability [7].
It means to adopt a revolution way in Maintenance because the conventional approaches based on failures studies of target system are not well adapted to support regeneration issues. It is needed to develop new requirements in the maintenance system design by extending the current notion of operational conditions to the notion of regeneration health management. These new considerations have to be thought not only for the target system but also for the maintenance system itself (a maintenance system is also a system consuming and producing material with sustainability problems; recursion principle).
At least, it has to lead in consistence with sustainability properties to promote life cycle approach (life cycle system; life cycle maintenance [4]) to take into account the phases interactions; holistic approach or system thinking approach as defended by system engineering practices [8] to take into account system complexity and multi-disciplinary vision to manage asset as a whole; and functionality concept to maintain a service – a regeneration need and not a component feature.
These visions are fully in phase with current maintenance considerations defended through initiatives of engineering for producibility [9], life cycle analysis (LCA), design for manufacturing (DfM) – for environment (DfE) – for disassembly (DfD) – for recycling (DfR), green maintenance [10], “long life eco-products” …
Within these visions, processes such as Prognostics, Health Monitoring … are essential as advocated by PHM (Prognostics and Health Management) community. For example, Prognostics could be used not only for calculating a RUL as conventionally defined but for evaluating the energy consumption, the energy efficiency, the service achievement, the component health in the way to reuse it in another system, the evolution of a flow property to anticipate its transformation to a waste, the stock of the spare parts to manage it for reducing foot print related to spare parts transport [11] etc.
Thus the goal of this plenary talk planned during TES’2014 is to investigate the previous issues and challenges in order to analyze the necessary changes in maintenance (e.g. with regards to strategy, to organization, to objective) and to underline advanced maintenance services. In addition the maintenance engineering will be addressed in a cyclical perspective of the life cycle of the target systems. All these investigations will be illustrated with regards to potential benefits to show also their links with the Return Of Investment (ROI) constraint.