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Evaluation of the E/M Impedance Method as a SHM Technique for Large Civil Aircraft Spoilers: Analytical, Numerical and Experimental Studies Performed with Simple Structures

C. VIECHTBAUER, T. ERLINGER, M. SCHAGERL

Abstract


This article presents analytical, numerical and experimental results obtained by the electromechanical (E/M) impedance method. The ambitious future objective is to apply this classical SHM technique on wing spoilers of large civil aircraft’s as depicted in Figure 1. To evaluate this possible application, the E/M impedance method is first tested on simple structures. The demand to investigate possible monitoring systems for aeronautical industry is particularly motivated by composite components, such as the aircraft spoiler under consideration, which are highly sensitive against impact events. Hence, different SHM methods were developed over the last two decades to detect, locate, quantify and qualify damages in lightweight structures. One of the most promising SHM methods which seem to fulfil the requirements from industry is the E/M impedance method. The article starts with a brief discussion of the working principle of the E/M impedance method. To evaluate the applicability of this method it is then applied on simple one- and two-dimensional structures made of metal. Firstly, analytical considerations are made to understand the results and the principle of the E/M impedance method. Secondly, two different numerical modeling methods (a classical FEM and a coupled-field FEM method) are used. On the one hand to validate the analytical results and on the other hand to verify the numerical approach. The numerical model is identified to be a powerful and applicable approach particularly for complex structures as wing spoilers where analytical considerations become too cumbersome. Finally, the analytical and numerical results are validated and calibrated by measurements obtained in laboratory experiments as depicted in Figure 4. As a conclusion it is explained how this research shall serve as the basis to optimize the E/M impedance method for application on complex composite structures.

doi: 10.12783/SHM2015/92


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