Semi Automatic Failure Analysis Based on Simulation Models

Abstract

Classical risk assessment and risk management which is gaining importance in many industries is usually based on well defined processes and uses techniques like FTA and FMEA. However, classical risk analysis techniques like FTA and FMEA should ideally be automated, at least to some extent and without loss of effectiveness, to enable fast and cost effective iterations of system modelling and risk analysis that can meet the tight cost and time constraints of most offshore projects. This paper is focused on the presentation of a new concept and tool extension for model-based synthesis of fault trees and FMEAs in which these failure analyses are automatically constructed from engineering design models, e.g. simulation models that have been augmented with information about the local propagation of failures. The simulation model is developed in the commercial system modelling tool SimulationX. The proposed process enables the automatic generation of both fault trees and FMEA tables in a single run of the tool, allowing the FMEA and fault trees to share failure data and allowing the FMEA to include failures caused by multiple basic events. As it is a largely automated process, it could be easily iterated to enable the continuous assessment of evolving designs. It provides an automatic generation of fault trees and FMEA tables for multiple top events in a single run of the tool. The potential benefits from application of this technique and tool are substantial and include simplifying the analysis, easing the examination of effects of design modifications on safety and keeping the safety analyses consistent with the design. Furthermore, the presented approach combines the benefits of simulation and risk analysis in one tool. The benefits of this approach are demonstrated by the example of a blow out preventer for a subsea installation valve.