粗晶组织材料的超声检测有限元仿真

The acoustic characteristics of coarse-grained metal materials are complex due to the coarse grain, anisotropy, and non-uniformity. Ultrasonic testing has a poor signal to noise ratio because of severe waveform distortion, energy attenuation, and structural scattering that occur when ultrasonic waves propagate inside it. To investigate the propagation law of ultrasonic waves in coarse-grained materials and provide theoretical guidance for the ultrasonic testing scheme, a finite element simulation modeling method for ultrasonic testing of coarse-grained materials was proposed. A two-dimensional grain model of the material was generated based on the Voronoi diagram algorithm. The anisotropic orientation of the grains was defined through the form of the material elasticity tensor. A finite element acoustic simulation method that enables parametric calculations was established. The simulation modeling research was carried out in terms of both acoustic attenuation and full matrix capture (FMC). A simulation model of the acoustic attenuation measurement of nickel-based high-temperature alloy GH4169 was established. A comprehensive matrix capture data acquisition simulation model was developed for titanium alloys using additive manufacturing, and the acoustic attenuation patterns of ultrasonic waves of various frequencies at various anisotropy indexes and grain sizes were simulated and examined. The signal-to-noise ratios of total focusing method (TFM) imaging at different anisotropy indexes and different detection directions were simulated and analyzed. The phase coherence factor (PCF) denoising imaging was performed on the TFM imaging results of flat bottom hole defects. The signal-to-noise ratio of simulated and experimental flat bottom hole defects is improved by 23.52 dB and 24.72 dB, respectively. GH4169 specimens with different average grain sizes were prepared by heat treatment. The simulation approach’s validity is confirmed by the results of the acoustic attenuation measurement experiments conducted on GH4169 specimens and the TFM imaging studies conducted on a titanium alloy specimen employing additive manufacturing.