Analysing the Fault Behavior of a Complex Mechanical System for Diagnosis: A Bond Graph-Based Approach

Multiple faults diagnosis is a critical problem in mechanical fault diagnosis. Fault behavior analysis aims to find out the response characteristics of operating parameters under different faults and is the most primitive task for multiple faults diagnosis. This paper proposes a bond graph-based approach to analyse the mechanical fault behavior for diagnosis. The analytical model of an engineering system is firstly established via bond graph. The temporal causal graph is derived from the bond graph model to depict the analytic relationships system variables. The operating parameters response characteristics under different faults are then derived by representing the faults with abnormal change of system variables. The approach is illustrated via an engine lubrication system. The presented approach avoids time-consuming formula transformation which is necessary in mathematical model-based approach, and therefore provides an efficient for fault behavior analysis.