Research Projects

In recent years, auxetic metamaterial structures have emerged as a new class of artificial materials with unique properties, such as negative Poisson’s ratio, negative stiffness and negative compressibility. Unlike conventional structures, these structures with negative Poisson’s ratio shrink laterally when subjected to compressive loads. The most common auxetic structures are 2D re-entrant honeycombs, which have been extensively studied for their large deformation behavior, shear properties and stiffness. Analytical solutions have proven useful in predicting the behavior of these structures, but their non-uniform strain distribution under transverse loading limits their practical application. To address this issue, a non-linear constitutive model is proposed that promotes uniform strain distribution throughout the auxetic structure, with a focus on aerospace applications. The micromechanical aspects of the material will be considered in the development of the model, using a thermodynamically consistent framework that offers insight into the material’s microstructure evolution, rather than relying on phenomenological descriptions. Numerical analyses based on the finite element method will be conducted to validate and evaluate the analytical solutions. Once the efficacy of the model is established, various auxetic structure configurations can be analyzed to determine optimal mechanical and geometric properties under general electro-thermo-mechanical loading conditions. Thereafter, the reliability of the designed graded auxetic metamaterial structures will be analyzed with the help of test results for bending stresses as statistical tool using Weibull distribution. Consequently, one can use the S–N curves at the various reliability levels for the industrial applications of graded auxetic metamaterial structures. This can aid in the design of smart systems that incorporate auxetic metamaterial structures with tunable mechanical properties.