Fabrication, characterization and analytical modeling of gradient auxetic closed cell foams

Abstract Auxetic (negative Poisson’s ratio) and gradient open cell foams have shown promise for their conformability high impact energy absorption—useful in applications like protective equipment, footwear prosthetics. Recent methods fabricated auxetic closed foam by steaming conventional foam. Methods developed herein control the structure of foam, to produce novel intentionally anisotropic Pins passed through constrained or stretched regions during further modify structure, impart gradients Young’s modulus ratios. Fabricated had ratios between 1 −1. Imparted moduli 1–12 MPa were similar used footwear, prosthesis, helmets other protection. The effect changes on ratio are explained combining analytical models