Dynamic Gain Correction Map for Automated Ultrasonic Inspection of Composite Structures
ABSTRACT
Automated Ultrasonic Testing (UT) plays a vital role in the aerospace industry, especially for inspecting large, complex composite parts and structures. One of the main challenges in ultrasonic inspection arises from the geometric variations of these parts, which affect ultrasonic wave propagation and result in defect detection variations across different regions of an inspected part. In particular, significant changes in part curvature and, in the case of transmission C-scans, variations in thickness can cause notable differences in signal amplitude. This requires either localized interpretation of UT signals or multiple C-scans at varying receiver gains to ensure complete coverage.
To automatically address these sensitivity variations, a novel Gain Correction technique has been developed and patented by TecScan. This technique automates the defect interpretation process by using gain variation maps generated from calibrated reference parts. Instead of adjusting detection thresholds, the Gain Correction technique uses these maps to dynamically adjust the gain, ensuring consistent signal interpretation while reducing the need for manual adjustments.
This paper presents the benefits of implementing this Gain Correction method, particularly in terms of normalization of the signal amplitude in the case of through-transmission scanning, and its impact on flaw detection and sizing within complex composite aerospace parts and structures.
Article published in the CINDE Journal (Oct/Nov/Dec 2024).
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Dynamic-Gain-Correction-Map.pdf
