English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

To guarantee an economic application of carbon fibre reinforced plastics (CFRP) throughout the entire product life cycle, the long term operational reliability and reparability of the products must be assured. The typical repair process starts with the defect detection and the defect evaluation. Based on the size and position of the defects the mechanical properties are evaluated and the most efficient repair process is selected. Therefore, the accuracy of the defect detection is essential for an economic repair process. One approach to detect defects in CFRP is the active lock-in thermography, which is an imaging non-destructive testing method. The application of image processing algorithms on phase images enables automated defect detection in CFRP components. The determination of the depth position of defects is still a challenge since the phase images contain a superposition of different depth layers. This paper introduces a method to quantitatively evaluate the 3D defect geometry from a stack of thermography images captured with different excitation frequencies. The phase images of blind bore holes are analysed. Digital evaluation criteria, e.g. area, enveloping circle and position, are defined. Algorithms for image correction, feature extraction and image analysis are implemented for automated defect detection. The stack of thermography images captured with different excitation frequencies is used to estimate the defect's depth range. With the given thermal diffusivity and the excitation frequency the depth information is calculated. The results are visualized three-dimensionally. The method is validated by the comparison of the experimental results with calibrated coordinate measuring machine data.

Method for Quantitative 3D Evaluation of Defects in CFRP Using Active Lock-in Thermography