MODELING THE EFFECTS OF NEGATIVE POISSONS RATIOS IN CONTINUOUS-FIBER COMPOSITES

Finite-element methods have been used to examine the elastic propertie s of continuous-fibre reinforced composites. Consideration has been gi ven to the possibilities of using either reinforcing or matrix constit uents with large negative Poisson's ratios (with values of -1.0 less-t han-or-equal-to nu less-than-or-equal-to 0.3). It is shown that a larg e negative Poisson's ratio can lead directly to considerably enhanced transverse moduli without altering the longitudinal moduli. For exampl e, changing the matrix Poisson's ratio from 0.3 to -0.9 and keeping al l other constituent properties constant produces an almost four-fold i ncrease in the composite transverse modulus.