the end of wave ultrasonic imaging method
Figure 3 Schematic diagram of ultrasonic wave detection end of the end of wave amplitude reduction caused by many reasons, including differences in thickness, texture, grain size and surface roughness, so the use of bottom wave ultrasound imaging required to detect when the upper and lower parts of the parallel interface,abercrombie dublin, material uniformity, surface roughness and the same coupling conditions, defects larger than where the beam cross section, to minimize the volatility of the value of other factors at the end of fall, to improve the quality and reliability testing. Li Jianwen et al: Ultrasound imaging of the end of wave 3-wave imaging ultrasound at the end of test-object detection and analysis of GB7233-1987 standard reference block of the ZGS, which has nine 2mm flat-bottomed holes, the depth from the surface to 5 L, respectively , 10,15,20,25,abercrombie düsseldorf,30,35,40 and 45mm (Figure 4). Detection range of 230mm × 15mm. Flooding and its full-wave ultrasonic data acquisition, and characteristics of different values ??of ultrasound imaging method for imaging the collected data are compared. Amplitude and depth of defect imaging results shown in Figure 5 and 6, showing defects amplitude imaging can detect only about five flat-bottomed holes, and depth imaging can detect eight flat-bottom hole defects. This is because the reference block thickness of 50mm, to detect the location of defects in the surface of the distance the greater the spread of the ultrasonic sound path longer, the greater the attenuation of sound energy, the defect signal to noise ratio is low, identify difficulties and even obliterated by noise , it can only barely detected five flat-bottomed holes. The depth of the imaging signal as long as the defect wave amplitude than the noise signal is high, waves can be based on the maximum amplitude defects calculated flaw depth location of ultrasound imaging, as is the use of ultrasonic flaw depth value as the amount of imaging features,abercrombie madrid, so imaging results not affect the size of amplitude defects (defects in the premise that the maximum amplitude wave is higher than the maximum amplitude of the noise), but the depth of the imaging sound waves due to strong interface, the RF signal waveform has a certain width,abercrombie singapore, close to the defect signal on the interface easy to interface annihilation wave signal, the signal gg negligent reference block diagram Figure 4ZGS mm1 summer summer l negligent Figure 5 defect amplitude imaging results O50l00l50200250 length / mm-wave depth imaging defects in Figure 6 the results difficult to choose the gate settings, so detection of ultrasound imaging can detect only eight flat-bottomed holes. Use at the end of the imaging amplitude signal when there is not difficult to choose the gate settings and defects weak signal problem. Select the gate only need to select the signal wave to the end. At the end of the wave amplitude is very strong, defect exists, at the end of wave direction can be made visible, the amplitude decreases rapidly, according to amplitude changes in the end can determine whether the defects, according to the end and then amplitude changes in ultrasound imaging, the imaging results shown in Figure 7, showing the use of bottom wave ultrasound imaging can show the nine flat-bottomed holes. El8120 length / mm Figure 7 bottom amplitude imaging results 4 Conclusion The bottom wave imaging can improve the system gain. Amplitude because of the high end, there are defects in the large amplitude changes, the system requires only a low gain can detect defects waves; and direct extraction of defect wave imaging, the system needs to achieve high gain, it can be relatively high amplitude waveform defects. The disadvantage of the bottom wave imaging can not be the end of the wave changes according to other characteristics of the defects (such as frequency and depth, etc.) for analysis, can not take on the end of wave signals such as filtering and noise reduction signal processing methods to improve signal to noise ratio and improve image quality . Ultrasound imaging is the end of the direct wave signal amplitude defect imaging using an effective supplement. References: [1] Zheng Zhongxing, Hu Shaohai, Teng Yongping, P and other portable ultrasound scanning system software design [J]. Non-destructive testing, 1998,20 (8) :214-218 [2] Chen Fang cylindrical workpiece c / B scan imaging system [A] Chinese Mechanical Engineering Society Sixth Annual Meeting of Society of Nondestructive Testing Proceedings Ec]. Beijing: 1995. EC Luo Wei. Manual scan CCD video image positioning ultrasound imaging study ED]. Beijing: Tsinghua University, 2001. E4] Wu Di, Zhang Zhao Dong, Han Xiufu, and so on. Universal scanning software development and application of imaging detection EJ]. Non-destructive testing, 2003,25 (8) :403-406. [5] Sen wood Marina. Image of the ultrasonic flaw detector developed [J]. Non-destructive testing, 1996,18 (5) :148-15O. [6] Tang Yongping, Zheng Zhongxing, Cao made the United States, and so on. Ultrasound imaging system signal processing and image display method EJ]. Non-destructive testing. 1995,17 (11) :311-314 [7] Chinese Mechanical Engineering Society Society of Nondestructive Testing Code. Ultrasonic flaw detection [Z] Beijing: Mechanical Industry Press, 19,902,005 No. 27, No. 9 459
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