TY  - JOUR
ID  - eprints2543
EP  -  476
VL  - 116
TI  - Homogenization of periodic hexa- and tetrachiral cellular solids 
AV  - none
Y1  - 2014/10//
KW  - Auxetic materials; Chirality; Non-local homogenization;   Cellular materials
UR  - http://www.sciencedirect.com/science/article/pii/S0263822314002438
JF  - Composite Structures
A1  - Bacigalupo, Andrea
A1  - Gambarotta, Luigi
SN  - 0263-8223
PB  - Elsevier
N2  - Abstract The homogenization of periodic hexachiral and tetrachiral honeycombs is dealt with two different techniques. The first is based on a micropolar homogenization. The second approach, developed to analyse two-dimensional periodic cells consisting of deformable portions such as the ring, the ligaments and possibly a filling material, is based on a second gradient homogenization developed by the authors. The obtained elastic moduli depend on the parameter of chirality, namely the angle of inclination of the ligaments with respect to the grid of lines connecting the centers of the rings. For hexachiral cells the auxetic property of the lattice together with the elastic coupling modulus between the normal and the asymmetric strains is obtained; a property that has been confirmed here for the tetrachiral lattice. Unlike the hexagonal lattice, the classical constitutive equations of the tetragonal lattice turns out to be characterized by the coupling between the normal and shear strains through an elastic modulus that is an odd function of the parameter of chirality. Moreover, this lattice is found to exhibit a remarkable variability of the Young?s modulus and of the Poisson?s ratio with the direction of the applied uniaxial stress. Finally, a simulation of experimental results is carried out. 
SP  - 461 
ER  -