Anisotropy factors and hydrostatic parameters of 1–3-type piezo-active composites with auxetic polymer matrices

Results on electromechanical properties and their anisotropy in 1–3-type composites with auxetic polyethylene matrices (Poisson's ratios from –0.83 to –0.20) are reported. The role of elastic properties of the auxetic component in forming a large piezoelectric anisotropy and hydrostatic piezoelectric coefficients d* h ≈ (1000–1500) pC/N and g* h ≈ (500– 600) mV.m/N, figures of merit, and electromechanical coupling factors is studied. Condition d*33/d*31→±∞ is valid at the volume fraction of ceramic 0.22≤ m*≤ 0.33, and m* correlates with the ratio c11/|c12| of elastic moduli of polymer. The effect of the aspect ratio of the elliptic cross section of rods on the volume-fraction dependence of d*3j , the piezoelectric anisotropy, and hydrostatic response is analysed.