Composite materials, due to their lightweight nature and superior mechanical properties, are widely used in various industries, including aerospace, automotive, and civil engineering. designing these materials in the form of lattice structures, particularly with properties such as a negative Poisson’s ratio, introduces unique mechanical advantages. In this study, auxetic lattice structures were fabricated using expanded metal sheets and braided lattice composite materials. The manufacturing process involved preparing individual samples, reinforcing their edges with adhesive, and connecting them with yarns to form the final structure. To improve resistance to local buckling and enhance energy absorption capacity, foam was used as a complementary material within the structures. Quasi-static compression tests were conducted to eva‎luate the mechanical performance, assessing characteristics such as energy absorption, specific energy absorption, mean force, and crushing force efficiency. Numerical simulations were also performed using Abaqus software, employing shell elements and the Hashin damage model for the composite samples, and elastic-plastic behavior for the metallic samples. The results demonstrated that combining auxetic geometry with composite materials significantly improves mechanical performance. The addition of foam notably increased energy absorption and reduced local buckling, particularly in composite samples, where energy absorption improved by up to threefold. However, the added foam also increased the overall weight, slightly reducing specific energy absorption. Reinforcement with adhesive improved the maximum load capacity during certain loading stages. The numerical results showed good agreement with experimental data, validating the effectiveness of the finite element model in predicting force-displacement behavior and energy absorption characteristics. This research provides comprehensive experimental and numerical insights, highlighting the potential for designing lightweight, durable structures with high energy absorption capabilities for advanced industrial applications.

رضا جعفري ندوشن , علي لقماني

محمد مهدي عابدي

محمد مشايخي , محمد سيلاني