AVIC General’s self-developed all-composite fuselage AG300 aircraft is a new kind of business jet based on carbon fiber composite material

using the curing oven molding

which is high-efficiency than conventional autoclave molding

but the porosity is bigger than that of the traditional process. The size and distribution of porosity directly affects the mechanical properties of structure

particularly vital member with stress concentration

so the need is urgent for reliable and accurate nondestructive evaluation of their porosity. We introduce a kind of preparation method for composite material porosity block by spraying solvent

using the ultrasonic attenuation method and metallographic analysis to carry out the calibration of the predecess or experical formula. We compare the porosities from calculated empirical formula and metallographic analysis

and draw the fitting curve. The error is not more than 0.4%

which verifies application possibility of this empirical formula in the engineering practice.