Tuning the Mechanical Properties of the Anti-Tetrachiral System Using Nonuniform Ligament Thickness

The mechanical properties of the anti-tetrachiral structure having the thickness of the ligament changing symmetrically around the center are investigated using analytical and numerical methods. For the purpose of deriving a theoretical model, the Euler-Bernoulli beam theory is used to determine the relation among the acting moment, the angle of rotation of the nodes, and the bending energy stored. Analysis of the results indicates that a change in geometry has a minor effect on Poisson's ratio, if any at all; however, it can result in relatively large changes in Young's modulus. Hence, it is shown that the mechanical properties can be altered selectively by adjusting the geometric features of chiral structures. The indications of the analytical model are validated using numerical methods for different values of the geometric parameters and are found to be in good agreement. In the process, it is shown that there are regions of the parameter space where the mechanical properties of the anti-tetrachiral are insensitive to variations in certain geometric dimensions.