Void-containing materials with tailored Poisson's ratio

Assuming square, hexagonal, and random packed arrays of nonoverlapping iden tical parallel cylindrical voids dispersed in an aluminum matrix, we have c alculated numerically the concentration dependence of the transverse Poisso n's ratios. It was shown that the transverse Poisson's ratio of the hexagon al and random packed arrays approached 1 upon increasing the concentration of voids while the ratio of the square packed array along the principal con tinuation directions approached 0. Experimental measurements were carried o ut on rectangular aluminum bricks with identical cylindrical holes drilled in square and hexagonal packed arrays. Experimental results were in good ag reement with numerical predictions. We then demonstrated, based on the nume rical and experimental results, that by varying the spatial arrangement of the holes and their volume fraction, one can design and manufacture voided materials with a tailored Poisson's ratio between 0 and 1. In practice, tho se with a high Poisson's ratio, i.e., close to 1, can be used to amplify th e lateral responses of the structures while those with a low one, i.e., clo se to 0, can largely attenuate the lateral responses and can therefore be u sed in situations where stringent lateral stability is needed. (C) 2000 Ame rican Institute of Physics. [S0021-8979(00)04519-9].