System Reliability Analysis


Investigate the influence of component faults or structural faults on the system behavior and analyze fault interactions in a system. Mechanical faults, for example, in joints, gears, shafts, springs or couplings due to breakage or slippage lead to a reduction in the transmitted forces or torques. Similarly, the reduction of electrical current due to poor or open connections in an electrical system or the reduction of the mass flow in a hydraulic system due to leakage or blockage can cause undesirable system behavior. The elements of this library represent such system faults and help you develop and perform system reliability analyses in an efficient and structured way.

The following figure shows a model which was augmented with Component Faults and Connector Faults from the Systems Reliability Analysis (SRA) library [1]. One of the resistors was replaced with its fault-augmented counterpart. A Connector Fault representing a short-to-ground was added to the connection between the inductor and the capacitor. The connection between the two resistors is cut by a Connector Fault representing a loose contact. An additional switchable connection (Bridge Fault) represents a short circuit between two junctions in circuits of consuming components.

Figure 1: A model of an electrical circuit augmented with faults

Note: In the diagram view, the red F in the red circle indicates elements that represent active faults: connection and parametric faults. The grey F in the grey circle indicates elements that represent inactive faults (e.g. looseContact in the figure above).

As shown in the figure, a model can consist of components from different libraries. Fault modeling affects the behavior of components (Component Faults) or changes the flow of sizes between components (Connector Faults).

The SRA library also contains a series of basic elements from which various types are derived with the option to create more through the right-click menu. Based on these basic elements (base classes), it is possible to automatically detect and systematically read and monitor fault models in a system model using the SRA add-in (see also [2]-[4]). The aforementioned SRA add-in can provide an overview of all the fault components in an active SimulationX model. It guides you intuitively through the entire process of analyzing the model, running variation calculations and performing result analyses.


[1] A. Kolesnikov, D. Tretsiak, M. Cameron.: "Systematic Simulation of Fault Behavior by Analysis of Vehicle Dynamics", Proceedings of the 13th International Modelica Conference, May 2019, doi: 10.3384/ecp19157451.

[2] J. Gundermann, A. Kolesnikov, M. Cameron, T. Blochwitz.: "The Fault library - A new Modelica library allows for the systematic simulation of non-nominal system behavior", Proceedings of the 2nd Japanese Modelica Conference, May 2018, doi: 10.3384/ecp18148161.

[3] A. Kolesnikov, M. Andreev, A. Abel.: "The Fault-Augmented Approach for the Systematic Simulation of Fault Behavior in Multi-Domain Systems in Aerospace", SAE Technical Paper, November 2018, doi: 10.4271/2018-01-1917.

[4] M. Andreev, A. Kolesnikov, U. Grätz, J. Gundermann.: "Simulation-based system reliability analysis of electrohydraulic actuator with dual modular redundancy", 12th International Fluid Power Conference, October 2020, Paper 14-2, pages 333-342.