Development of a technology for expanding the causal relationships among faults using physical formula

Abstract

We are developing a technology that supports FTA (Fault Tree Analysis) to reduce omissions of fault factors and improve efficiency. In this study, we developed a technology for expanding the causal relationships among faults using physical formula in order to generate a mutually exclusive and collectively exhaustive fault tree. We devised a logic of expansion from formulas based on the concept that there is a causal relationship between the variables on the left and right side of a formula. In addition, we devised a technique to narrow down only factors that could physically occur by using the correlation of variables on the left and right side of a formula. By using physical formulas of a fastening component as an example, we verified that mutually exclusive and collectively exhaustive fault tree was generated from causal models based on physical formulas properly.