A model evaluating the signal loss of the double transmitted acoustic beams through random rough surfaces was established based on the Fresnel approximation and phase- screen approximation. A simple analytical solutio...A model evaluating the signal loss of the double transmitted acoustic beams through random rough surfaces was established based on the Fresnel approximation and phase- screen approximation. A simple analytical solution was achieved using the exponential substi- tution approach to remove the nonlinear integral terms. The factors that affect the signal of double transmissions from random rough surfaces were analyzed. The research results demon- strated that the signal loss is not only related to the root-mean-squire height of the roughness, but also to the distance of wave traveling in the materials. The model can be very helpful for improving the reliability of NDT (Non-Destructive Testing).展开更多
In the point of application to ultrasonic nondestructive testing of surface stress and defect in polymer component, the oblique suxface wave transducer is investigated on its acoustic property and especially the mecha...In the point of application to ultrasonic nondestructive testing of surface stress and defect in polymer component, the oblique suxface wave transducer is investigated on its acoustic property and especially the mechanism of acoustic attenuation of acoustic entrant material inside the transducer. A new kind of room temperature vulcanized silicone elastomer as wedge material, in which ultrasound can propagate in very low speed with weak attenuation, is developed through a great deal of trials. The corresponding ultrasonic transducer is also designed for further researches and application to detect surface stress and surface crack in aerospace transparent component.展开更多
文摘A model evaluating the signal loss of the double transmitted acoustic beams through random rough surfaces was established based on the Fresnel approximation and phase- screen approximation. A simple analytical solution was achieved using the exponential substi- tution approach to remove the nonlinear integral terms. The factors that affect the signal of double transmissions from random rough surfaces were analyzed. The research results demon- strated that the signal loss is not only related to the root-mean-squire height of the roughness, but also to the distance of wave traveling in the materials. The model can be very helpful for improving the reliability of NDT (Non-Destructive Testing).
文摘In the point of application to ultrasonic nondestructive testing of surface stress and defect in polymer component, the oblique suxface wave transducer is investigated on its acoustic property and especially the mechanism of acoustic attenuation of acoustic entrant material inside the transducer. A new kind of room temperature vulcanized silicone elastomer as wedge material, in which ultrasound can propagate in very low speed with weak attenuation, is developed through a great deal of trials. The corresponding ultrasonic transducer is also designed for further researches and application to detect surface stress and surface crack in aerospace transparent component.
