EVALUATION OF FAILURE DIAGNOSIS IN CONCEPTUAL DESIGN OF MECHANICAL SYSTEMS

This paper discuses a methodology for improving quality and reducing l ife cycle costs of mechanical systems. The principal concept is that a system can be designed, in the conceptual stages, to be easier to dia gnose for failures. To perform this, functional decomposition and form -to-function. mapping are utilized to demonstrate the relation of desi gn to diagnosis and for diagnosis itself. Four diagnosability metrics are developed and four hypothetical conceptual designs are evaluated f or diagnosability and compared An example is presented wherein three c onceptual designs for a toolhead positioning system ale evaluated for diagnosability at two levels of abstraction and the results compared. The area of design for diagnosis offers promise in improving system qu ality and reducing life cycle cost; research is continuing to refine a nd integrate the procedures with other aspects of the concurrent engin eering design process.