Evaluation of Different Techniques of Active Thermography for Quantification of Artificial Defects in Fiber-Reinforced Composites Using Thermal and Phase Contrast Data Analysis

• Published in: International journal of thermophysics Vol. 39; no. 5; pp. 1 - 37
• Main Authors: Maierhofer, Christiane, Röllig, Mathias, Gower, Michael, Lodeiro, Maria, Baker, Graham, Monte, Christian, Adibekyan, Albert, Gutschwager, Berndt, Knazowicka, Lenka, Blahut, Ales
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2018; Springer Nature B.V
• Subjects: Carbon fiber reinforced plastics; Chassis; Classical Mechanics; Component reliability; Condensed Matter Physics; Data analysis; Defects; Destructive testing; Electric power generation; Fiber composites; Fiber reinforced polymers; Gas pipelines; Geophysics; Glass fiber reinforced plastics; Glass-epoxy composites; Icppp 19; ICPPP-19: Selected Papers of the 19th International Conference on Photoacoustic and Photothermal Phenomena; Industrial Chemistry/Chemical Engineering; Matrix materials; Natural gas; Nondestructive testing; Petroleum pipelines; Phase contrast; Physical Chemistry; Physics; Physics and Astronomy; Polyamide resins; Reliability analysis; Shearography; Thermodynamics; Thermography; Tidal energy; Flash excitation; 10.105; Delaminations; Flat bottom holes; 10.200; Lock-in excitation; Active thermography; GFRP; CFRP
• ISSN: 0195-928X; 1572-9567
• DOI: 10.1007/s10765-018-2378-z

For assuring the safety and reliability of components and constructions in energy applications made of fiber-reinforced polymers (e.g., blades of wind turbines and tidal power plants, engine chassis, flexible oil and gas pipelines) innovative non-destructive testing methods are required. Within the European project VITCEA complementary methods (shearography, microwave, ultrasonics and thermography) have been further developed and validated. Together with partners from the industry, test specimens have been constructed and selected on-site containing different artificial and natural defect artefacts. As base materials, carbon and glass fibers in different orientations and layering embedded in different matrix materials (epoxy, polyamide) have been considered. In this contribution, the validation of flash and lock-in thermography to these testing problems is presented. Data analysis is based on thermal contrasts and phase evaluation techniques. Experimental data are compared to analytical and numerical models. Among others, the influence of two different types of artificial defects (flat bottom holes and delaminations) with varying diameters and depths and of two different materials (CFRP and GFRP) with unidirectional and quasi-isotropic fiber alignment is discussed.