The sandwich panel structures have been widely used in many industrial applications because of their high mechanical properties. The middle layer of these structures is very important factor in controlling and enhancing their mechanical performance under various loading scenarios. The re-entrant lattice configurations, are prominent candidates that can be used as the middle layer in such sandwich structures because of several reasons namely the simplicity in tuning their elastic (e.g., values of Poisson’s ratio and elastic stiffness) and plastic (e.g., high strength-to-weight ratio) properties by only adjusting the geometrical features of the constituting unit cells. Here, we investigated the response of a three-layered sandwich plate with a re-entrant core lattice under flexural bending using analytical (i.e., zig-zag theory), computational (i.e., finite element) and experimental tests. We also analyzed the effects of different geometrical parameters (e.g., angle, thicknesses, and length to the height ratio of unit cells) of re-entrant lattice structures on the overall mechanical behavior of sandwich structures. We found that the core structures with auxetic behavior (i.e., negative Poisson’s ratio) resulted in a higher bending strength and a minimum out-of-plane shear stress as compared to those with conventional lattices. Our results can pave way in designing advanced engineered sandwich structures with architected core lattices for aerospace and biomedical applications.

Shear deformation theory is employed for electro elastic analysis of a functionally graded piezoelectric cylinder as a physical sensor for estimation and controlling the internal pressure. Except Poisson ratio, all mechanical and electrical properties are graded along the radial coordinate system. The present paper develops the previous study using the shear deformation theory as a capable and advantageous theory instead of plane elasticity theory. Two radial and axial deformations are simulated using the first order shear deformation theory. Electric potential is supposed as a quadratic function along the thickness direction and as an unknown function along the longitudinal direction. Comparison between the present results at the regions that are adequate far from two ends of the cylinder with the results of plane elasticity theory justifies accuracy and capability of the present method. Some useful graphical and numerical results are presented in this study. The discussed problem in this paper has many advantageous properties and application in measurement and controlling of the mechanical and electrical components because of using the functionally graded materials instead of an isotropic material.DOI: http://dx.doi.org/10.5755/j01.mech.18.3.1875