A fuzzy weighted wedge mechanism for feasibility assessment of system reliability during conceptual design

Abstract

A structured and disciplined system engineering process is essential for the effective and efficient development of products and systems which are responsive to customer requirements and competitive within a global marketplace. Rigor and discipline during the later phases of system design (preliminary and detail) cannot compensate for an ill-conceived concept and for premature commitments made during the conceptual design phase. Its significance notwithstanding, conceptual design analysis and evaluation has been largely ignored by the research and development community. This paper addresses the feasibility of system reliability during the conceptual design analysis and evaluation process. Feasibility assessment involves compliance analysis (versus separation or ranking analysis) between the required and predicted values of the reliability parameter. A fuzzy quality function deployment (QFD) mechanism is applied for the delineation of a fuzzy target or required value of system reliability. Thereafter, system reliability is predicted or estimated for each potential system design concept. These predictions and estimations may be expressed as fuzzy or stochastic measures. More often than not, however, the resolution and extent of information available during conceptual design may only allow fuzzy estimations and predictions. This paper presents the development of a weighted wedge to facilitate compliance analysis between fuzzy required and predicted system reliability values.