Flexible Mechanoluminescent SrAl2O4:Eu Film with Tracking Performance of CFRP Fracture Phenomena

Abstract

Non-destructive testing of carbon-fiber-reinforced plastic (CFRP) laminates with bidirectional fiber bundles (twill-weave) using a mechanoluminescence (ML) technique was proposed. The dynamic strain distributions and fracture phenomena of the CFRP laminates in the tensile testing were evaluated by the fabricated ML sensor consisting of SrAl2O4:Eu (SAOE) powder and epoxy resin. The ML images for the ML sensor attached to the CFRP laminates with bidirectional fiber bundles gave a net-like ML intensity distribution similar to the original twill weave pattern. Specifically, it was found that the ML intensity on the longitudinal fiber bundle, which is the same as the tensile direction, is higher than that on the transverse fiber bundle. This indicates that the ML sensor can visualize the load share between fiber bundles in different directions of the CFRP laminate with high spatial resolution. Meanwhile, the ML sensor could also visualize the ultrafast discontinuous fracture process of the CFRP laminates and its stress distribution. The amount of SAOE powder in the ML sensor affects the tracking performance of the crack propagation. A higher SAOE amount leads to a fracture of the ML sensor itself, and a lower SAOE amount leads to poor ML characteristics.

Principles, properties, and sensing applications of mechanoluminescence materials

“…Fujio et al used an ML technique to evaluate strain distribution and crack growth of bidirectional braided carbon fiber reinforced plastic laminates, visualizing crack growth and the associated stress distribution. 174 4.4. Medical health ML material is a ''smart'' material that can produce a fast detectable signal response to various external stimuli and has the advantages of biocompatibility, spatio-temporal controllability and precise strength.…”

“…Fujio et al used an ML technique to evaluate strain distribution and crack growth of bidirectional braided carbon fiber reinforced plastic laminates, visualizing crack growth and the associated stress distribution. 174…”

A flexible organic mechanoluminophore device

“…A flexible mechanoluminophore device that displays desired patterns by light emission based upon mechanical stimulations holds great promise in a wide range of applications, ranging from human-machine interfaces 1 , to smart textile 2 , to health monitoring 3 , to wearables 4 , to anti-counterfeiting 5 , and to self-powered displays 6 . Primarily motivated to visualize the mechanical stress on materials and structures, there has been a growing interest in developing mechanoluminescence (ML) materials 7 – 10 . Although there are some advances on mechanoluminophore materials and devices 7 – 18 , a soft, flexible counterpart has been very nascent, and more importantly, it needs to be discernible under ambient light.…”

A stress-charged non-Newtonian-fluid persistent luminescent material

“…Previously, SrAl 2 O 4 :Eu 2+ have been reported to emit PersL under stress, but it still requires preirradiation for PersL. [29][30][31] . This is the rst time for us to observe stress-charged PersL, which is valuable for pracitcal applications.…”