Study on the Adhesive Wettability and Nano‐ SiO ₂ Dispersibility at the Interface of Joints in Fiber Metal Laminates Under Vibration Process

This study developed a novel pneumatic hammer vibration assisted vacuum bag pressure process to improve adhesive wettability on metal surfaces and nano‐SiO 2 dispersion within the adhesive layer of fiber metal laminates. Tensile test results show that compared with the vacuum bag pressure process, the optimal vibration and the high‐pressure process improve the failure strength by approximately 3% and 10% in adhesive with 0 wt.% SiO 2 respectively. Interfacial failure mode analysis indicates that the wettability under the high‐pressure process is inferior to the vibration process, and its higher strength is mainly attributable to the increased fiber volume fraction in adhesive layer. In adhesive with 0.5 wt.% SiO 2 , the vibration and the high‐pressure process improve the failure strength by approximately 12% and 1%, respectively, demonstrating the role of vibration in promoting nanoparticle dispersion. Relevant micrographs shows that micro‐crack propagates through nano‐SiO 2 agglomerates, whereas dispersed nano‐SiO 2 from vibration inhibits crack growth. Finally, interfacial adsorption and three‐SiO 2 models are established to elucidate the mechanisms. The adsorption model indicates that vibration enables polymer chains to penetrate deeper surface micro‐pits, improving wettability. The three‐SiO 2 model suggests that vibration drives polymer chains between nano‐SiO 2 , generating steric hindrance and improving dispersion.