Piezoelectric Composites with 3-1 Connectivity and a Foamed Polyurethane Matrix

The effect of porosity on the hydrostatic piezoelectric sensitivity was explored for 3–1 composites with a polyurethane matrix. Hydrostatic sensitivity increases rapidly with volume of porosity, and dh increases from 12 x10−12to >200X10-12 C/N when 40% porosity is incorporated. These composites become strongly nonlinear at >I MPa and consequently would be limited to shallow water operation.