Effects of mechanical properties of stainless-steel ultra-thin strip on the interlaminar shear properties of fiber metal laminates

Shear properties can reflect the bonding strength between interfaces, which has an important influence on the overall mechanical properties and durability of fiber metal laminates (FMLs). In this study, a series of carbon-fiber/stainless-steel ultra-thin strip laminates (CUSFMLs) with two different layer structures was prepared by using carbon-fiber prepreg and soft, semi-hard, and hard 100 mu m-thick stainless-steel ultra-thin strip, respectively. The interlaminar shear strength (ILSS) and interlayer failure modes of CUSFML were obtained through a series of short-beam shear tests. The evolution process of interlayer damage of CUSFML was simulated by the ABAQUS/Implicit module incorporating the UMAT subroutine. Results indicated that the ILSS of CUSFML can be enhanced by decreasing the metal volume content and reducing the metal's mechanical properties. Compared with the E-layup, which had a higher metal volume content of 35.3%, the F-layup with 18.2% metal content showed an approximately 19.8% improvement in ILSS. Additionally, incorporating mechanically weaker soft-state ultra-thin stainless-steel strips into the CUSFML increased its ILSS by approximately 20.5%, compared with using hard-state ultra-thin stainless-steel strips. The CUSFML with a higher metal-volume content experienced damage concentrated on the contact area, which rapidly spread along the longitudinal direction due to its high strength and stiffness. Highlights Fiber metal laminate has economic and environmental benefits. The interlaminar shear strength affects fiber metal laminate lifespan. The influencing factors are metal mechanical properties and volume content. Heterogeneous interfaces had more abrupt changes than homogeneous interfaces.