Design-for-reliability starting from conceptual design

Design-For-Reliability (DFR) has been studied in various literature articles and engineering text books, however, there are few studies that systematically address Design-For-Reliability definition, theoretical foundation, and feasible practice during an entire design cycle starting from conceptual design throughout embodiment and detailed designs. It is observed that there is a significant gap between the engineering design discipline and the reliability discipline, that is, these two disciplines are not closely tied and integrated. Consequently, DFR during the design cycle, especially during an early design stage, is often merely a slogan. Aside from the above horizontal gap, there is a vertical gap: the gap between the conceptual DFR and embodiment DFR. Literature review indicates that weak connections, if any, are made between them.;The objective of this research is to establish a systematic DFR framework and methodology that can be implemented starting from conceptual design and functional design, and evolving with continuation of DFR activities throughout the embodiment design and detailed design to address the two aforementioned gaps. The center piece of the DFR framework, developed through this research to support functional and conceptual design-for-reliability, is the conceptual stress and conceptual strength interference theory (CSCSIT). CSCSIT parameterizes the conceptual design space with meaningful reliability parameters addressable during the conceptual and functional design stage. This set of reliability parameters can be carried out from the conceptual design to the embodiment design for potential seamless DFR connection. CSCSIT also serves as a foundation for developing a unified modeling approach that unifies and integrates the functional modeling, behavioral modeling and reliability modeling. To support DFR data aggregation, a modified Bayesian Reliability Analysis (BRA) process with a prior and data validation and adjustment scheme (PDVAS) is developed to enhance the validity of design-for-reliability data analysis. To support risk informed design decision, a design based risk analysis (DBRA) is formulated.;The DFR frame work with CSCSIT, the unified modeling, BRA with PDVAS, and DBRA are applied to a liquid propulsion rocket engine design as an illustrative and validation case for the theory, methodology and techniques developed in this research.;The research is expected to contribute significantly to the field of the design-for-reliability by: (1) developing a novel approach to parameterize the conceptual design space with reliability related parameters for conceptual design-forreliability that fills the gap between engineering design and reliability (horizontal gap); (2) building a bridge between the conceptual design-for-reliability and embodiment design-for-reliability with CSCSIT to seamlessly address reliability throughout the entire design cycle to fill in the vertical gap; (3) developing a unified modeling approach among functional modeling, behavioral modeling and reliability modeling, a detailed reliability data aggregation technique, and a design based risk analysis method for a viable design-for-reliability analysis and risk informed decision throughout the entire design cycle.