A novel approach to fortify metal-composite T-joints with high strength and toughness has emerged through the integration of 3D printed auxetic metal stiffeners. Developed by researchers at King Abdullah University of Science and Technology (KAUST), their method has demonstrated a substantial enhancement in joint performance.
The proposed stiffener design, featuring a combination of bulk web and re-entrant structure flange, was made using selective laser melting 3D printing. Through meticulous testing, it has demonstrated significant advantages over conventional joints.
Pull-off tests have revealed a striking 266% increase in specific strength compared to baseline joints, alongside a staggering 38.2-fold rise in toughness. This improvement is attributed to the delayed damage initiation facilitated by the stiffener’s unique architecture.
Auxetic materials are those that demonstrate a negative Posisson’s ration, meaning when compressed, the material gets thinner. This is opposed to traditional materials and structures which are non-auxetic – they get thinner when stretched.
Unlike traditional joints where damage initiation typically occurs at the stiffener edge, the auxetic stiffener shifts this initiation point, enhancing the joint’s overall resilience. Furthermore, the negative Poisson’s ratio of the re-entrant structure effectively halts delamination growth post-damage initiation, further bolstering toughness.
The significance of this advancement lies in its potential to enhance metal-composite joint applications across various industries, including aerospace and automotive sectors. By offering unparalleled strength and toughness, these superior joints pave the way for lighter, more durable structures without compromising safety.
You can read the full paper, titled “3D printed auxetic metal stiffener for lightweight metal–composite T-joints with high strength and toughness” at this link.
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