Velocity of elastic waves in porous ceramic materials: influence of pore structure

A review has been undertaken of recently published data on ultrasonic velocity porosity for a variety of porous ceramic materials, including information on pore structure. These experimental data have been compared with data calculated using a spheroidal pore model incorporating information on pore volume fraction, shape, and orientation. Good agreement is obtained between experimental and calculated values, especially when fractional porosity is less than about 0.25, even when a single 'effective' pore shape is employed in the calculation. The agreement improves if a different pore shape for each porosity level (point by point analysis) is used. The predictive ability of the spheroidal pore model is thus demonstrated.