A Deep Learning Method for the Impact Damage Segmentation of Curve-Shaped CFRP Specimens Inspected by Infrared Thermography

Abstract

Advanced materials such as continuous carbon fiber-reinforced thermoplastic (CFRP) laminates are commonly used in many industries, mainly because of their strength, stiffness to weight ratio, toughness, weldability, and repairability. Structural components working in harsh environments such as satellites are permanently exposed to some sort of damage during their lifetimes. To detect and characterize these damages, non-destructive testing and evaluation techniques are essential tools, especially for composite materials. In this study, artificial intelligence was applied in combination with infrared thermography to detected and segment impact damage on curved laminates that were previously submitted to a severe thermal stress cycles and subsequent ballistic impacts. Segmentation was performed on both mid-wave and long-wave infrared sequences obtained simultaneously during pulsed thermography experiments by means of a deep neural network. A deep neural network was trained for each wavelength. Both networks generated satisfactory results. The model trained with mid-wave images achieved an F1-score of 92.74% and the model trained with long-wave images achieved an F1-score of 87.39%.

Latest Advances in Common Signal Processing of Pulsed Thermography for Enhanced Detectability: A Review

“…Hu et al [87] conducted a comparative analysis of POD based on RNCC after applying various types of signal processing to images acquired using the ECPT technique. Wei et al [88], by grafting a deep neural network to pulsed infrared thermography, conducted a study to detect impact damage of curved laminates exposed to a thermal stress cycle and subsequent ballistic impact and segment them into medium and long wave infrared sequences.…”

Research on Tensile Properties of Carbon Fiber Composite Laminates

“…Lin et al [7] conducted a comparative analysis of the dynamic failure behavior of flat and curved panel structures of woven basalt/epoxy laminates under blast loading, emphasizing the important influence of structural curvature on the dynamic response. Wei et al [8] carried out experiments and numerical simulations on the high-speed penetration of laminates and concluded that, in addition to fiber failure, laminates under penetration loads also include spalling and matrix cracking. Penetration velocity, penetration angle, fiber layup, and laminate structure form generate rich research results on the dynamic behavior and failure of laminate structures under tensile loads [9].…”

Active Thermography for the Detection of Sub-Surface Defects on a Curved and Coated GFRP-Structure

“…In addition to the investigations on flat plates, there are also approaches for the thermographic investigation of curved surfaces. Wei et al used pulse thermography to investigate impact damage on a curved CFRP specimen that was exposed to both thermal loads and ballistic impacts [21]. Both principal component analysis (PCA) and specially trained neural networks were able to detect the damage.…”