A systematic literature review of changeability in engineering systems along the life cycle

The escalating dynamism of external pressures and the persistent demand from stakeholders for systems to maintain value amidst continuous change necessitates a re-evaluation of how system value is delivered. This literature review addresses the ambiguously defined concept of changeability, which spans domains, incorporates various 'ilities' and has in part impeded the formulation of effective comprehensive industry strategies. As a successful approach to cope with change, changeability involves the design of engineering systems that can continue to change, quickly (agile) and easily (flexible). This paper elucidates how changeability is defined, and the elements used to evaluate change in engineering systems. Subsequently, it reviews the methods and strategies employed to quantify, measure, and analyse changeability and change-related 'ilities'. An examination of various cases and applied research sets allowed the researchers to illustrate the roles, features and effects of changeability in the design of complex engineering systems throughout the entire lifecycle, thereby confirming and consolidating how changeability is both perceived and executed. Based on these findings, future research related to the quantification of changeability levels, and the cost implications associated are proposed, with an emphasis on utilising and integrating systems models (model-based systems engineering) to standardise and simplify implementation across various engineering systems.