Damage imaging post processing for delamination size assessment of CFRP aeronautic structures

Thanks to their high strength to mass ratio, composite materials are now widespread in the aerospace industry. Nevertheless, this type of material is sub- ject to internal damages like delamination. In order to detect and localize these damages, robust and precise Structural Health Monitoring algorithms exist for this purpose and have been validated experimentally. However, in order to avoid struc- tures catastrophic failures and to estimate their residual life, there is still a huge need of reliable damage size assessment methods. In this paper, a damage quanti cation method is proposed. This strategy is based on the extraction of a damage size sen- sitive feature computed from damage imaging results. Here damage imaging stands for methods that use ultrasonic Lamb waves-based map of damage localization like- lihood index. This feature is extracted from each labelled example of a training set in order to infer a mathematical model used to predict the area of a delamination of unknown damages. The proposed method is successfully validated on experimental data carried out on CFRP plate samples equipped with a piezoelectric transducers network.This work has received funding from the European Union's Horizon 2020 research and innovation program under the REMAP project (grant agreement number 769288). https://h2020-remap.eu

A model-based approach for statistical assessment of detection and localization performance of guided wave–based imaging techniques

International audienceThis paper aims at providing a framework for assessing the detection and localization per-formance of guided wave-based structural health monitoring (SHM) imaging systems. Theassessment exploits a damage identification metric (DIM) providing a diagnostic of the struc-ture from an image of the scatterers generated by the system, allowing detection, localization,and size estimation of the damage. Statistical probability of detection (POD) and probabilityof localization (POL) curves are produced based on values of the DIM for several damage sizesand positions. Instead of relying on arduous measurements on a significant number of struc-tures instrumented in the same way, a model-based approach is considered in this paper forestimating POD and POL curves numerically. This approach is first illustrated on a simplisticmodel, which allows characterizing the robustness of the SHM system for various levels of noisein test signals. An experimental test case using a more realistic case with an artificial damageis then considered for validating the approach. A good agreement between experimental andnumerical values of the DIM and derived POD and POL curves is observed