Load-bearing characteristics of 3D auxetic structures made with carbon fiber reinforced polymer composite

This paper presents a study of 3D novel hybrid auxetic structures made with carbon fiber reinforced polymer (CFRP) laminate composite based on the stretch-dominated mechanism. The homogenized mechanical characteristics of the designed structures, including Young's modulus, shear modulus, and Poisson's ratio, are evaluated via theoretical analysis and finite element simulation. The results exhibit that the structures have negative Poisson's ratio values in all the selected ranges of the design geometry parameters. The multi-objective optimization method is employed to achieve the optimized geometry parameters based on maximizing the stiffness and minimizing the relative density responses. Meanwhile, 2D fabricated auxetic sheets are assembled to build 3D structures through the interlocking method, and quasi-static compressive tests are performed to study their mechanical behaviors. The axial and lateral strains are evaluated by the strain gauge and video extensometer to measure the negative Poisson's ratio values through compressive tests. The results indicate that the proposed structures exhibit superior stiffness and high elongation percentage, suggesting them as a strong candidate for the next generation of load-bearing auxetic structures.