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Experimental Evaluation of Vibration-based Damage Identification Methods on a Composite Aircraft Structure with Internally-mounted Piezo Diaphragm Sensors



Maintenance strategies in various fields of industry, including aerospace applications, are shifting from time-scheduled to condition based strategies. An important requirement to allow this shift is to acquire knowledge on the failure modes and mechanisms of the system under observation. This implies for the aerospace industry that knowledge on composite failure modes, such as a typical skin-stiffener delamination, is essential. Prior research of the authors revealed the use of vibration based structural health monitoring, with application on laboratory specimen. The next step is to apply the methods developed to a more complex real aerospace structure. The objective of this study is to employ an internally-mounted piezo electric transducers based SHM strategy to a composite aerospace-related structure. Previous studies in laboratory-scale composite studies have revealed that delamination in a composite structure can be detected and localized by calculating the Modal Strain Energy (MSE) from vibration measurements of a pristine and damaged structure. In this study, a Carbon Fiber Reinforced Plastic (CFRP) aileron having a complex and representative aircraft geometry is used to evaluate the SHM approach where internally-mounted piezo diaphragms are used to calculate MSE damage indicator. The structure was excited by an electro-mechanical shaker inducing a 50 to 1000 Hz sine sweep. 19 piezo diaphragms, divided over two rows, are internally mounted on and next to a stringer where impact was applied to. The results show that the MSE damage indicator derived from the internal sensors can detect and (partly) localize the damage.

doi: 10.12783/SHM2015/177

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