Nonmonotonic concentration dependence of piezoelectric coefficients of 1–3 composites

Reported are results of studying nonmonotonic concentration dependences of piezoelectric coefficients e3j*, d3j* and their anisotropy ζe and ζd, respectively, which pertain to the 1–3 composite. Changing the piezoelectric properties of the composite is plotted by variations of ratios between elastic and piezoelectric constants of components and for various volume fractions of one of the components. Systems of conditions providing extreme points of the e3j* and d3j* functions and discontinuity points of the ζe and ζd functions are formulated. The role of electromechanical constants of the components and some connections between these constants in reaching the nonmonotonicity are discussed.