Results of Nondestructive Inspection of Layered Composites Using IR Thermography and Ultrasonics

Abstract

Polymeric layered composites exhibit a variety of damages following in service loading conditions, like delamination, matrix cracking or even fibre breaking. Detection of such damages and assessing their extension and severity is vital during maintenance cycle, in view of keeping the normal operational reliability. For local inspections, IR thermography and ultrasonic scanning are among the best valued NDT methods. The paper describes the inspections performed by IR active thermography, in different variants, and pulse-echo ultrasonic scanning on GFRP. A variety of layered composites and defects/damages were inspected and the results are evaluated independently, in some cases being compared each other, with valuable conclusions for the users of the mentioned NDI techniques.

Composite Materials Flaws Detection and Measurement by Infrared Thermography

“…The theoretical study allows establishing the examination parameters [4,5]. The heat transfer by conduction is essential in differentiating the zones with defects found inside the material.…”

“…Variability of results and measurement uncertainty often causes the discouragement of operators to estimate the size of defects by IRT inspection. To measure the defect dimensions is a subject of many actual studies [4,5,6]. Although, infrared thermography is limited to the detection of relatively shallow defects (a few millimeters under the surface), however, the most common defects of composite materials widely used in the aircraft, automotive, oil industries etc.…”