Adaptive mechanical properties and stretchability of novel chainmail fabrics based on overlapping tessellation strategies

This study introduces a novel design and additive manufacturing of technical textiles to achieve tunable mechanical properties through the tessellations of a singular material. The design of these chainmail fabrics was inspired by overlapping tessellation strategies found in biological structures. Two types of chainmail fabrics —BCC and FCC were designed to exhibit high flexibility and stretchability with two-dimensional degrees of freedom. The fabrics were designed to bend along two orthogonal axes and drape around curved surfaces. Furthermore, the relative placement of the unit cells was adjusted to selectively arrest the degrees of freedom, resulting in chainmail fabrics with tunable flexibilities and mechanical properties. Four fabrics for each design Fabric-A, Fabric-B, Fabric-C, and Fabric-D were developed with varying degrees of freedom. All the designed chainmail fabrics were additively manufactured using HP-MJF powder bed fusion technology with a polyamide-12 material. The mechanical properties of the fabricated samples were evaluated through experimental tension tests and numerical simulations. The fabricated BCC and FCC chainmail fabrics exhibited a stress-free zone, followed by an elastoplastic zone, with different mechanical properties observed at different orientations. The FCC fabrics outperformed the BCC fabrics with 45° orientation, exhibiting excellent load-bearing properties, and the 0° orientation showed superior energy absorption capacity. The numerical simulations accurately predicted the mechanical properties and failure locations. Fabric-A was highly flexible but had compromised load-bearing and energy-absorption abilities, whereas Fabric-D acted as a rigid lattice structure with exceptional load-bearing and energy-absorbing properties. FCC fabrics are easier to manufacture using various polymer additive processes owing to their supportless nature. Tunable technical fabrics such as these have potential applications in lightweight and adaptive spinal posture-correcting braces as well as in protective equipment.