| 航空铝试块疲劳裂纹相控阵超声成像检测 |
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| 引用本文： | 彭朝勇,胥松柏,杜创洲,张杰.航空铝试块疲劳裂纹相控阵超声成像检测[J].北京航空航天大学学报,2022,48(12):2398-2404. |
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| 作者姓名： | 彭朝勇 胥松柏 杜创洲 张杰 |
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| 作者单位： | 1.西南交通大学 物理科学与技术学院, 成都 610031 |
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| 基金项目： | 国家自然科学基金61501381 |
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| 摘 要： | 表面疲劳裂纹扩展可导致结构失效，利用相控阵超声成像技术监测疲劳裂纹，获取结构完整性评价所需裂纹信息，可及时对结构失效提出安全预警。采用三点弯曲疲劳试验法在航空铝试块上生长疲劳裂纹，对裂纹开口面材料进行逐步切削来获得不同长度的疲劳裂纹，利用相控阵超声全矩阵采集(FMC)和全聚焦方法(TFM)获得的裂纹尖端和开口图像信息来监测裂纹扩展和测量裂纹长度，并测试了相控阵超声探头放置位置、裂纹张开/闭合、裂纹表面粗糙度对超声成像检测效果的影响。研究结果表明:相控阵超声探头从裂纹侧面入射检测能更好地对裂纹进行超声成像，并真实反映材料内部裂纹扩展前缘形貌。当疲劳裂纹长度大于3倍超声波长时，裂纹尖端和开口图像完全分离，相控阵超声全矩阵采集和全聚焦成像技术可有效测量裂纹长度，测量误差小于0.2 mm。相比裂纹张开时，疲劳裂纹闭合效应会使裂纹尖端超声图像信号减弱4.5 dB，长度测量值小0.6 mm。
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| 关 键 词： | 疲劳裂纹 相控阵超声 全矩阵采集/全聚集方法 成像特征 裂纹长度 |
| 收稿时间： | 2021-04-01 |
Ultrasonic phased array imaging on aviation aluminum block fatigue crack |
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| Affiliation: | 1.School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, China2.Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, UK |
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| Abstract: | Surface breaking fatigue crack propagation can lead to structural failure. The phased array ultrasonic imaging technology is used to monitor fatigue cracks and can obtain the crack information required for structural integrity evaluation. For the purpose of evaluating the structural integrity of a structure, fatigue cracks are monitored using the phased array ultrasonic imaging technique, which may also collect the crack information needed. It can promptly provide safety warnings before structural failures. The three-point bending fatigue test method is used to grow fatigue crack on an aviation aluminum test block. Fatigue cracks of different lengths are obtained by gradually cutting the material awayfrom the crack mouth surface. Phased array ultrasonic full matrix capture (FMC) and total focusing method (TFM) are applied by using fatigue crack tip and mouth image information to monitor crack growth and measure crack length. The test influences on ultrasonic imaging of phased array ultrasonic probe positioning, fatigue crack opening/closing, crack surface roughness are also carried out. The results show that the ultrasonic probe can better image the crack when irradiated from the side of the crack, which can truly reflect the morphology of the crack front inside the material. When the fatigue crack length is more than 3 times the ultrasonic length, the image of the crack tip and crack mouth is totally separated, the phased array ultrasonic FMC/TFM imaging technology can effectively measure the crack length, and the measurement error is less than 0.2 mm. Compared with being opened, the fatigue crack closing effect can weaken the reflection of the ultrasonic image signal at the crack tip by 4.5 dB, and the length measurement value is 0.6 mm smaller. |
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