Mechanical Properties of a Novel Ultraductile Composite Bar with Spirally Wound FRP Strands

Enhancing the strength and ductility of metallic materials simultaneously is crucial for numerous industrial applications, yet it remains a formidable challenge due to the typical trade-off between these two properties. This study introduces an innovative approach to surmount this challenge by employing a composite bar design that leverages necking inhibition mechanisms for simultaneous improvements in both strength and ductility. The composite bars, comprising aluminum cores reinforced with spirally wound fiber-reinforced polymer (FRP) strands, were fabricated in various configurations to investigate different necking behaviors. Through uniaxial testing, the composite bars exhibited notable increases in both strength and ductility, attributed to the strategic design of the FRP winding angle and FRP content. This design effectively modulates the necking behavior, thereby enhancing the composite bars' mechanical properties. Analysis of the strain distribution further elucidated the role of the spiral FRP strands in necking prevention. The composite bar design method outlined in this study offers a viable strategy for enhancing the mechanical performance of metallic materials, significantly reducing the risk of abrupt failure under high loads and deformations.