Optimizing the functional design and life cycle cost of mechanical systems using genetic algorithms

PurposeThis paper proposes a new simultaneous optimization model of the industrial systems design and maintenance. This model aims to help the designer in searching for technical solutions and the product architecture by integrating the maintenance issues from the design stage. The goal is to reduce the life-cycle cost (LCC) of the studied system.Design/methodology/approachLiterature indicates that the different approaches used in the design for maintenance (DFM) methods are limited to the simultaneous characterization of the reliability and the maintainability of a multicomponent system as well as the modeling of the dynamic maintenance. This article proposes to go further in the optimization of the product, by simultaneously characterizing the design, in terms of reliability and maintainability, as well as the dynamic planning of the maintenance operations. This combinatorial characterization is performed by a two-level hybrid algorithm based on the genetic algorithms.FindingsThe proposed tool offers, depending on the life-cycle expectation, the desired availability, the desired business model (sales or rental), simulations in terms of the LCCs, and so an optimal product architecture.Research limitations/implicationsIn this article, the term “design” is limited to reliability properties, possible redundancies, component accessibility (maintainability), and levels of monitoring information.Originality/valueThis work is distinguished by the use of a hybrid optimization algorithm (two-level computation) using genetic algorithms. The first level is to identify an optimal design configuration that takes into account the LCC criterion. The second level consists in proposing a dynamic and optimal maintenance plan based on the maintenance-free operating period (MFOP) concept that takes into account certain criteria, such as replacement costs or the reliability of the system.

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Consideration of Failure Diagnosis in Conceptual Design of Mechanical Systems

5th International Conference on Design Theory and Methodology ◽

10.1115/detc1993-0019 ◽

1993 ◽

Author(s):

David N. Ruff ◽

Robert K. Paasch

Keyword(s):

Life Cycle ◽

Engineering Design ◽

Concurrent Engineering ◽

Life Cycle Cost ◽

Mechanical Systems ◽

Design Guidelines ◽

Failure Diagnosis ◽

Design For Manufacturability ◽

System Quality ◽

Function Mapping

Abstract A methodology for improving quality and reducing life cycle costs of mechanical systems is described. The principle concept is that a system can be designed, in the conceptual stages, to be easier to diagnose for failures. To perform this, functional decomposition and form to function mapping are utilized both as a model of design and to demonstrate the relation of diagnosis to design. Design guidelines from other disciplines of engineering and concurrent engineering principles are applied to enhance the concept. The affects of the different elements of concurrent engineering on each other are explored. Of the elements of concurrent engineering, design for manufacturability affects the others the greatest. Design for manufacturability principles impact the size of field replaceable units and can improve the ease of failure diagnosis of a system. For a hypothetical case, form to function mapping that would create a difficult to diagnose system is redesigned to reduce the difficulty of failure diagnosis. Further, three diagnosability metrics are developed and four hypothetical conceptual designs are evaluated for diagnosability and compared The area of design for diagnosis offers promise in improving system quality and reducing life cycle cost; research is continuing to refine and integrate the procedures with other components of the concurrent engineering design process.

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Evaluation of Failure Diagnosis in Conceptual Design of Mechanical Systems

Journal of Mechanical Design ◽

10.1115/1.2828789 ◽

1997 ◽

Vol 119 (1) ◽

pp. 57-64 ◽

Cited By ~ 15

Author(s):

R. K. Paasch ◽

D. N. Ruff

Keyword(s):

Life Cycle ◽

Concurrent Engineering ◽

Life Cycle Cost ◽

Mechanical Systems ◽

Failure Diagnosis ◽

Life Cycle Costs ◽

System Quality ◽

Levels Of Abstraction ◽

Engineering Design Process ◽

Conceptual Designs

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

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