Dr. Raj Das

Abstract:

Negative Poisson’s Ratio (or NPR) is the primary mechanical property of auxetic metamaterials that results in an improved mechanical performance compared to regular material arrangements [1]. The distinctive characteristics that are usually improved are stiffness and impact resistance due to selective and controlled densification [2]. The paper explores the effects of changing the parameters of a cylindrical auxetic structure under static and dynamic conditions on the mechanical characteristics. The auxetic cylinder shell was constructed using 2D auxetic unit cells.

Finite Element Analysis (FEA) through the ABAQUS simulation software was used to model quasi-static compression and impact loading for the auxetic structures. This analysis included a mesh-convergence study to ensure the suitability of mesh resolution for the accuracy of the model results. The change in the aspect ratio (ratio of the height to the diameter) of the cylinder structure and the radial thickness of 2D auxetic unit cells were performed, while the size of the unit cells was kept constant. The change in these parameters was found to change the mechanical properties of the overall structure. The cubical configuration with the aspect ratio close to unity provides NPR values close to 1 as well, while the change in the stiffness depends on the scale of the structure. Such processes can be used to tailor the Poisson’s Ratio and stiffness of lightweight cylinder auxetic structures for different applications.