Method of Computer-Aided FTA (Fault Tree Analysis) in Reliability Design and Development; Using Knowledge Management Based on Quantity Dimension Indexing and Block Diagram

In this paper the authors propose computerized support for Fault Tree Analysis (FTA) based on new knowledge management in product design. FTA is a method of analyzing and visualizing the causes of a fault event by Fault Tree diagram (FT diagram) that has a tree structure with logical step. When we develop the new product, we use FTA to analyze the fault events, to extract design parameters, and to plan test programs in Jatco's development process. Although FTA is an effective analytical tool for resolving problems, improving design quality and planning test programs, it is not easy to complete the FT diagram of a fault on Automatic Transmission and the component system without a mistake. To solve this problem, we propose the following approach using Computer-Aided knowledge management based on Quantity Dimension Indexing and block diagram. We classify FT diagrams into component failure, system failure, and control failure diagrams. An FT diagram of component failure is created with a computerized support tool based on quantity dimension indexing that was proposed [9] [10]. An FT diagram of system failure and control failure is created with a computerized support tool utilizing block diagrams that were created with design engineers. We developed this software of Computer-Aided FTA for design engineers by the collaborative research group (Jatco Ltd, The University of Tokyo and National Institute of Advanced Industrial Science and Technology (AIST)). We report the efficiency and effectiveness of this support method (software) for FTA based on evaluating results in actual development process, and describe the possible feasibility and future study for proposal methods in complex system development.