4 results about "Scattering attenuation" patented technology

The invention provides a method for detecting a welding seam by adopting an ultrasonic flaw detector, and belongs to the technical field of welding seam detection. The welding seam is divided into small welding sections, and each small welding section is subjected to multi-direction ultrasonic scanning; a scattering attenuation coefficient and a signal-to-noise ratio parameter are calculated to determine an optimal detection position direction vector group and an optimal time frequency group, and then a high-frequency narrow pulse probe is matched with a phased array focusing technology to carry out second detection according to the optimized parameter; and the identified defects are classified and evaluated according to the near surface blind area characteristic parameters, secondary verification is performed by adopting a surface wave supplementary detection algorithm, and finally a weld defect position distribution diagram is generated, so that the technical problem of low defect detection accuracy caused by serious ultrasonic scattering attenuation of a coarse grain structure weld material is solved.

The invention relates to a material sound velocity measurement method based on an envelope cross-correlation algorithm, relates to the technical field of automatic detection, and solves the technical problem of serious waveform distortion interference in sound velocity measurement of an internal non-uniform material in the prior art. The method comprises the following steps: initialization setting and reference acquisition; performing point-by-point scanning on the current scanning surface of the tested sample to obtain sample echoes; drawing a sound velocity distribution diagram of the current scanning surface of the tested sample; rotating the sample to be measured and continuously measuring until the detection of the three orthogonal surfaces is completed; the average sound velocity of the tested sample is obtained. By applying the material sound velocity measurement method, scattering attenuation and frequency dispersion effect interference caused by material anisotropy can be eliminated, a period jump error caused by carrier phase ambiguity is reduced, the signal-to-noise ratio of a detection signal is effectively improved, automation and high repeatability of sound velocity measurement are achieved, and the measurement accuracy is improved. And the recognition accuracy of the small sound velocity difference is improved.

The ultrasonic detection method comprises the following steps: dividing a bolt into an effective stress section and an unstressed section along the length direction of the bolt based on the axial stress distribution of the bolt; constructing a sound intensity transmission coefficient model corresponding to the effective stress section based on the sound impedance corresponding to the effective stress section and the sound impedance corresponding to the unstressed section; obtaining a sound intensity attenuation model corresponding to the effective stress section based on the medium attenuation coefficient of the bolt and the sound intensity transmission coefficient model corresponding to the effective stress section; acquiring an echo signal corresponding to an emission longitudinal wave signal emitted from one end of the bolt along the length direction of the bolt, an acoustic impedance-bolt axial stress mapping model and a medium attenuation coefficient-bolt axial stress mapping model; and outputting the axial stress of the bolt based on the sound intensity attenuation model. The acoustic impedance interface effect is coupled with grain scattering attenuation, stress gradient and interface reflection interference are synchronously eliminated, stress is solved, and the detection precision of the axial stress of the bolt is remarkably improved.

This invention relates to a method for measuring the sound velocity of materials based on an envelope cross-correlation algorithm, belonging to the field of automated detection technology. It addresses the problem of severe waveform distortion interference in existing sound velocity measurements of internally inhomogeneous materials. The method includes the following steps: initialization settings and benchmark acquisition; point-by-point scanning of the current scanning surface of the sample to obtain sample echoes; plotting the sound velocity distribution map of the current scanning surface of the sample; rotating the sample to continue measurement until the detection of three orthogonal surfaces is completed; and obtaining the average sound velocity of the sample. Applying this material sound velocity measurement method can eliminate interference from scattering attenuation and dispersion effects caused by material anisotropy, reduce "period jump" errors caused by carrier phase ambiguity, effectively improve the signal-to-noise ratio of the detection signal, achieve automation and high repeatability of sound velocity measurement, and improve the accuracy of identifying minute sound velocity differences.