Energy absorption mechanism and cost-benefit assessment of UHMWPE and para-aramid hybrid fabrics for protective structures

UHMWPE (Ultra-High Molecular Weight Polyethylene) plain-weave fabric, characterized by its lightweight and high-strength properties, is widely used in protective equipment such as bulletproof vests and stab-resistant vests, serving as a key material for enhancing protective performance. This study systematically investigates the influence mechanism of interfacial properties on the energy absorption characteristics of UHMWPE-based protective structures through multi-scale experiments and numerical simulations, and establishes a cross-scale design methodology. Innovatively, an orthotropic constitutive model incorporating dynamic friction coefficients is constructed, combined with a modified Johnson-Cook failure criterion, to achieve high-precision simulation of the entire ballistic impact process (error < 3.5%). Additionally, a friction field prediction model considering strain rate effects is developed, and the friction evolution laws of UHMWPE and Para-aramid (Kevlar)fabrics under strain rates of 10 −3 and 10 −4 s −1 are obtained through MTS pull-out tests. The results show that: (1) there exists a critical yarn-yarn friction coefficient ( μ = 0.2); exceeding this value leads to a 19% reduction in energy absorption capacity, while viscous interfaces increase the energy dissipation peak by 16%; (2) UHMWPE shows kinetically-dominated absorption (58%) with high rate but high load, increasing damage risk. Para-aramid has friction-dominated absorption (53%) with lower rate but stable load. Hybrid fabrics use potential-dominated absorption (49%) at a moderate rate, balancing stability and protection. (3) 3–5 layers of UHMWPE fabric yield optimal cost-effectiveness, with the unit cost reduction rate of the HS+5U scheme reaching 2.74 m/(s·$), which is 91% higher than that of the hybrid scheme. (4) For HS+5U (5-ply UHMWPE), V50 is 520 m/s, meeting primary protection requirement. For hybrid solutions with U/K ≥ 3 (e.g., HS+6U+2K), V50 reaches 580 m/s (≥ 540 m/s), satisfying advanced protection requirement. This research provides critical references for the design of flexible protective structures and their engineering applications.