Experimental research on the acoustic transmission characteristics of refractory materials

The damage acoustic emission (AE) signal of refractories can be used to evaluate the classification and degree of the phase damage, which is different from the traditional damage location study in AE. In the analysis of AE signal, considering the nonuniformity of refractory inner structure, results of damage source inspection are usually affected by the signal transmission path. Therefore, the influence of transmitting path should be studied first. Piezoceramic material, capable of actuation and sensing, is commonly used to build AE probes. In this paper, two kinds of industrial refractories were selected as research objects and AE probes were chosen to generate emission acoustic signals. The relative amplitude attenuation coefficient and the relative energy attenuation coefficient were consequently designed as discriminant indicators to study the propagation characteristics of stress wave under different transmission paths and thicknesses. Results indicate that energy attenuation is higher than amplitude attenuation. Meanwhile, signal attenuation is principally proportional to transmission distance without directional selectivity. The above conclusions provide strong support to arrange AE sensors for nondestructive testing in refractory industry.