Integrated safety and reliability analysis methods for aircraft system development using multi-domain object-oriented models

Abstract

Safety and reliability are essential in commercial air transport. Therefore, safety assessment is an inherent part of the aircraft systems development process. Operational reliability has to be considered for economic reasons. Most of the state-of-the-art methods for safety and reliability analysis employ a binary representation of the system. One of these is fault tree analysis (FTA), a manual method that is still common today. Conducting safety or reliability analysis by means of FTA involves considerable effort. In addition, because of the binary, non-physical approach, such analysis tools remain uncoupled to other engineering tools. Nowadays, a multi-domain object-oriented approach has become the state-of-the-art in physical modelling and simulation. Such an approach enables an intuitive method of modelling, in which the objects, their boundaries and interconnections correspond to real existing components. This thesis contributes to the field of model-based methods for system safety and reliability analysis. Here, the most important innovation is that the proposed methods suit multi-domain object-oriented modelling based on differential-algebraic equations. Search techniques and algorithms founded on graph theory were devised in order to minimise the computing effort for conducting an analysis. The proposed methods enable establishing multi-disciplinary engineering tools for the conceptual design of fault-tolerant systems. The aim is improvement of system development and safety assessment processes.