Virtual Sensors for Diagnosis and Prognosis Purposes in the Context of Elastic Mechanical Structures

This contribution deals with a model-based approach for diagnosis and prognosis tasks in the context of elastic mechanical structures in conjunction with the Safety and Reliability Control Engineering (SRCE) concept. In elastic mechanical structures, faults are given by structural changes in mass and/or stiffness, caused by cracks, loss of material or, for example, by the internal delamination processes of carbon fiber laminate materials. The latter affects modern light weighted structures which are more and more used for example in aircraft constructions. Especially for such safety-critical systems, online and in-situ fault diagnosis are desired. Structural health monitoring (SHM) concepts deal with different tools to realize safe systems, applying fault monitoring, and repair mechanism in combination with approaches for monitoring the hazard rate of complete complex systems. The contribution provides new results for the application of the proportional-integral-observer (PIO) for the fault localization in elastic mechanical systems. At this, the PIO works as a virtual sensor. Moreover, the PIO can be applied for fault detection and estimation. Therewith it can provide inputs for the SRCE concept. That one gives a framework and strategy to calculate the actual reliability of a system under operation what may be used for the purpose of predictive/condition-based maintenance in the context of SHM concepts.