An Accurate Design Equation for the Maximum Deflection in a Class of Auxetic Sectorial Plates

Auxetic materials are solids that exhibit negative Poisson's ratio. The effect of material auxeticity (i.e., negativity of Poisson's ratio) is investigated herein on the maximum deflection of sectorial plates with Simply-Supported straight edges and Free curve edge (SSF). To aid the designer, an accurate and conveniently executable semi-empirical model has been developed herein, which is valid for the entire range of Poisson's ratio of isotropic solids and for the plate's sectorial angle from 30 to 90 degrees. Results from exact solution reveal that the maximum deflection reduces sharply with the reduction of Poisson's ratio from positive to mildly negative, but deflection reduction is marginal when the sectorial plate's Poisson's ratio changes from moderately negative to highly negative value. It is therefore suggested that (a) the use of auxetic materials is useful to limit the extent of SSF sectorial plate deflection, and that (b) the use of the developed semi-empirical model herein as a design equation gives greatly simplified but highly accurate maximum deflection prediction for SSF plates made from both conventional (positive Poisson's ratio) and auxetic (negative Poisson's ratio) materials.