Nondestructive detection of incipient thermal damage in glass fiber reinforced epoxy composite using the ultrasonic propagation imaging

Abstract

Incipient thermal damage (ITD) in polymer-matrix composites could cause substantial loss of material properties and it is notoriously difficult to be detected using nondestructive evaluation (NDE) techniques. The emerging ultrasonic propagation imaging (UPI) could be the solution for the detection problem and its detection probability for ITD was studied in this work. Glass fiber reinforced epoxy plate specimens insulted at temperatures ranging between 1.1 and 1.7 times of the glass transition temperature (Tg) for duration ranging between 5 and 30 min were inspected. The results in the form of statistically thresholded anomaly maps showed clear detection of ITD for specimens insulted at 1.4 and 1.7 times of Tg for 30 and 5 min, respectively, and partial detection for specimens insulted at 1.3 and 1.5 times of Tg for 30 and 10 min, respectively. Finally, an insulting duration-temperature plot with distinguished ITD undetectable, partially detectable, and fully detectable zones was estimated for references of future works.

Investigation of manufacturing defects in 3D-printed CFRP using laser ultrasonic testing and x-ray micro-computed tomography

“…LUT is a non-destructive inspection method that generally uses lasers to generate and detect ultrasound waves [20]. However, the laser is often combined with other transducers, such as piezoelectric transducers, according to the system configuration [21,22]. To inspect the two 3D-printed CFRP specimens and investigate their manufacturing defects, the through-transmission mode of LUT was implemented.…”

Investigation of Ib-Values for Determining Fracture Modes in Fiber-Reinforced Composite Materials by Acoustic Emission

“…Therefore, it is essential to consider and analyze failure modes (e.g., matrix cracking, interfacial failure, and fiber fracture), considering the fiber structure in the design of FRP materials [5][6][7][8]. A proper non-destructive test is required in order to monitor the damage that occurs during FRP testing and relate it to failure modes [9][10][11][12][13].…”