Energy Correlated Damage Indices in Fatigue Crack Extent Quantification

Abstract

Signals received by piezoelectric transducers (PZT) network can be influenced by many factors. Apart from environmental conditions, whose variability should be compensated, significant difference in a signal can be also caused by relative geometry changes of a designed sensors node, e.g. the damage localization and its orientation with respect to sensors location in the node. In the adopted approach a set of damage indices (DIs), carrying marginal signal information content and correlated with the total energy received by a given sensor are proposed. These are sensitive to the two main modes of guided wave interaction with a fatigue crack, i.e. its transmission and reflection from a damage. Detailed description of DIs detection capabilities are delivered in the paper. Two dimensional reduction techniques: Principal Component Analysis and Fishers Linear Discriminant are compared. The results of the data collected from specimen fatigue test are used to compare several classification models based on the emerged effective damage indices.

Damage identification in aircraft composite structures: A case study using various non-destructive testing techniques

“…Both of the effects can be captured by the proposed DI. The joint information from all of the network transducers can be merged in the Averaged Damage Indices (ADI) [29]:…”

A method to compensate non-damage-related influences on Damage Indices used for pitch-catch scheme of piezoelectric transducer based Structural Health Monitoring

“…For the purpose of indication of signal changes within a given PZT network consisting N transducers, Averaged Damage Indices (ADIs) were used 40,41…”

“…Therefore, they should be sensitive to the two main modes of guided waves interaction with cracks, that is, their reflection from a damage and transmission through it. Analogous DIs as given by equation ( 23) are extensively used in the literature, 5 for example, for fatigue cracks growth monitoring [19][20][21][22][23]40 or for impact damage detection. 41…”

Wykrywanie uszkodzeń w konstrukcji samolotu w trakcie realizacji pełnoskalowej próby zmęczeniowej z wykorzystaniem czujników zintegrowanych

“…Structural Health Monitoring -SHM) [6,7]. W artykule przedstawione zostanie podejście do monitorowania konstrukcji lotniczych z wykorzystaniem czujników piezoelektrycznych (PZT) generujących fale sprężyste, opracowywanym w ramach projektu SYMOST [8,9].…”