Sensing System Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Saga 841-0052, Japan.
Department of Molecular and Material Science, Kyushu University, Fukuoka 816-8580, Japan.
Sensors (Basel). 2022 Jul 22;22(15):5476. doi: 10.3390/s22155476.
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 SrAlO: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.
提出了一种使用机械发光（ML）技术对具有双向纤维束（斜纹编织）的碳纤维增强塑料（CFRP）层压板进行无损检测的方法。通过由 SrAlO:Eu（SAOE）粉末和环氧树脂制成的制造的 ML 传感器，评估了 CFRP 层压板在拉伸测试中的动态应变分布和断裂现象。对于附着在具有双向纤维束的 CFRP 层压板上的 ML 传感器的 ML 图像，给出了类似于原始斜纹编织图案的网状 ML 强度分布。具体而言，发现与拉伸方向相同的纵向纤维束上的 ML 强度高于横向纤维束上的 ML 强度。这表明 ML 传感器可以以高空间分辨率可视化 CFRP 层压板中不同方向的纤维束之间的载荷分配。同时，ML 传感器还可以可视化 CFRP 层压板的超快不连续断裂过程及其应力分布。ML 传感器中的 SAOE 粉末量会影响裂纹扩展的跟踪性能。较高的 SAOE 量会导致 ML 传感器本身断裂，而较低的 SAOE 量会导致 ML 特性变差。
