| After many decades of abundant government funding following the cold war, the commercial aerospace industry is transitioning to a new phase of autonomy where human and capital resources are increasingly limited. In this context, the investments related to subsystem technological developments are increasingly outsourced to suppliers. These first tier contractors are often shared among airframers. As a result, the access to new technologies is no longer the main factor for product differentiation. On the other hand, optimizing the aircraft system architecture for superior integrated performance of available technologies is more than ever a core competency to ensure product competitiveness. This highlights the need to consider architecting activities in conceptual design. Traditional system engineering methods, expected to support this capability, were more appropriate to coordinate progressive developments of subsystems within a fixed framework, rather than the exploration of architecture concepts and strategies.;In order to address this gap, a model-based architecting methodology is proposed. This methodology addresses limitations of traditional system engineering methods. The system engineering methods allow for the organization of developments, but are limited in their ability to explore and analyze new architectures. Therefore, the proposed methodology allows for expedient analysis of architectural concepts and the establishment of subsystem development strategies. Its process is implemented by an architecting team composed of subsystem experts and architects to respect existing industrial structures. The methodology uses the SysML language as a visual and organized means to define architectures. Using meta-modeling techniques, this definition is translated into an analysis model which automatically integrates subsystem analyses in a fashion that represents the specific architecture concepts described by the team. The resulting analysis automatically sizes the subsystems composing it, solves and optimizes the subsystem trade-offs, and synthesizes their information to derive architecture-level performance. The subsystem optimization is facilitated using the Coordinated Optimization method proposed in this dissertation. This method proposes a multi-level optimization setup. An architecture-level optimizer orchestrates the sizing of subsystems in order to optimize the aircraft as whole while maintaining subsystem expertise boundaries.;The proposed overall methodology enables the exploration of the architectural design space, via the acceleration of the analysis cycle of architecture concepts. The acceleration is primarily performed via the implementation of architecture analysis based on the automated integration of subsystem models. Architecture models which used to necessitate weeks of preparation can now be setup in hours. With this spectacular acceleration of the analysis setup, more architecture concepts can be explored, and better architectural solutions identified.;The benefits of the proposed methodology are not limited only to the exploration of the architecture concepts. It also formulates design requirements for subsystem developments. This formulation provides objective functions based on subsystem domain parameters which will guide their optimization toward architecture-level goals. This approach has been demonstrated to provide a formidable advantage in terms of the integrated performance compared to traditional system engineering approaches. This advantage is perceptible both by higher performance of the architecture after development and by a significant improvement in the probability of success in meeting system performance levels.;As a result this methodology empowers the system architects in their ability to identify the best architecture concepts and to perform subsystem integration in the best and most effective way possible. |
