Three-Dimensional Warp-Knitted Spacer Fabrics Functionalized with Conductive Shear-Stiffening Gel for Impact Buffering and Intelligent Sensing

Warp-knitted spacer fabrics (WKSFs) possess a three-dimensional porous architecture that makes them promising for impact protection and airdrop buffering, yet their lack of intrinsic conductivity and limited cyclic stability restrict intelligent monitoring applications. Here, a structure-function synergistic strategy is proposed by integrating WKSF with carbon-nanotube-modified shear-stiffening gel (cSSG) to construct a conductive, impact-adaptive composite. As a benefit from strain-rate-dependent stiffening and hierarchical energy dissipation, the WKSF-cSSG composite exhibits enhanced impact resistance while forming a stable three-dimensional conductive network. After cyclic preconditioning to suppress the Mullins effect, the composite delivers stable sensing outputs over 3200 cycles with a response time of 18 ms. Under drop-hammer impact, the electrical response shows rapid synchronization with mechanical dynamics, enabling quantitative discrimination of impact intensities. Furthermore, an intelligent airdrop buffering prototype integrating a nine-channel sensing array and deep-learning-assisted classification achieves accurate recognition of five landing postures, demonstrating a material-to-system solution for intelligent protection applications.