Fault location

Using Krein-space-based H-infinity estimation theory, a new approach to damage localisation and state identification, known as State Projection Estimation Error (SP2E), was developed in previous studies. Krein-space-based estimators are not known in structural dynamics, damage localisation and state identification. The SP2E method does not employ balance equations, material laws, kinematic formulations or chemical process models; instead, it solves an inverse problem (a system-theoretical black box). It is based on the decomposition of a multidimensional Popov function in conjunction with a coupled state-space model as the process model. Building on this, using the algebraic method of oblique projections, a unique parameter can be theoretically derived in state space as a damage indicator and localiser. In principle, the method is capable of operating in real time. From an engineering perspective, a process estimation error performance is selected as an indicator and evaluation measure for damage localisation.

The SP2E method has been prototypically tested on multiple occasions in laboratory experiments on a real mechanical system under ambient excitation, with very good results. Against this very positive background, the new SP2E methodology is to be further developed and investigated in theory and application.

The H-infinity estimators used enable the theoretical treatment of both deterministic and stochastic structural excitations. Ambient excitation is particularly advantageous for the system and damage identification of large mechanical structures. Methodologically, it is worth noting that the multi-sensor, process-oriented modelling employed can be carried out without knowledge of the excitation of the mechanical structure, relying solely on measurements of the structural response. In the planned project, the H-infinity theory will be introduced and validated for damage localisation and state identification. Among other things, approaches involving the application of mixed H-2/H-infinity estimation methods as well as square-root methods will be investigated. Significant developments are expected here, as these are novel in the fields of damage localisation and state identification.

A central component of the project is the theoretical further development of the SP2E method and its experimental verification. Here, the quality of damage localisation under disturbance influences and environmental and operating conditions will be validated. Laboratory tests will be initiated. Building on this, long-term tests will be carried out at an open-air test facility. Here, the influence of continuously changing environmental conditions (e.g. changes in excitation (wind), temperature) on the numerically identified structural behaviour for damage localisation must be taken into account. Furthermore, in preparation for industrial applications, pilot studies will be carried out on complex structures (e.g. bridges, wind turbines).