Progress in ultrasonic testing and imaging method for damage of carbon fiber composites
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摘要:
目的 碳纤维复合材料具有密度小、弹性高和韧性好等特点,被广泛应用于航空航天和汽车工业等领域。由于碳纤维复合材料制作工艺的复杂性和不稳定性以及服役期间易受环境的影响,易产生分层、孔隙、纤维褶皱等各种类型的损伤。因此,为了防止重大事故的发生,亟需在碳纤维复合材料制造加工和服役阶段及时检测出损伤,以实现碳纤维复合材料的质量控制和安全性能评估。 方法 针对碳纤维复合材料结构无损检测技术有很多, 如X射线检测法、涡流检测法、磁粉检测法、激光散斑干涉法、红外热成像法和超声无损检测法等。其中,超声无损检测技术因具有技术成熟、检测成本低、准确度高等优势,被广泛应用于碳纤维复合材料的检测。本文介绍了基于体波或导波的C扫描、相控阵、空气耦合、激光超声、光纤超声检测技术的原理、特点以及用于碳纤维复合材料损伤检测的研究现状。本文综述了最具有代表性的损伤诊断成像算法,包括全聚焦成像、三维可视化成像、层析成像、逆时偏移成像和概率成像方法。 结果 基于体波的检测技术能够实现碳纤维复合材料厚度方向上微小损伤的检测,现有研究检测碳纤维复合材料的样品厚度的范围约为3~6.4 mm,在检测频率为20 MHz时,能够检测到的碳纤维复合材料最小损伤直径约为 0.5 mm。基于导波的检测技术,检测的样品厚度范围一般为2.54~4 mm的碳纤维复合材料层合板,该技术具有检测范围广和检测效率高等优势,能够检测最小损伤直径约为3 mm。成像结果表明五种成像方法能够有效地实现碳纤维复合材料各种类型的损伤形貌图像。然而,这五种成像方法的可靠性都依赖于碳纤维复合材料传播模型的建立和换能器的设计与布局,因此,在实际工业损伤检测诊断成像前,应准确测量各检测样品的各层厚度、弹性常数、密度以及检测换能器的参数等。根据实际损伤诊断需求,选择相应的成像方法。 结论 超声检测技术是一种可靠的无损检测/结构健康监测手段,在碳纤维复合材料损伤检测领域具有广泛的应用前景。可有效地解决碳纤维复合材料的各种损伤类型的检测,具有操作简单、高效、成本低、检测精度高等特点。总结并对比了超声检测技术结合体波或导波检测的特点以及用于碳纤维复合材料损伤检测的研究现状。各超声检测与成像方法有不同的优缺点,应根据实际检测需求,选择合适的成像方法。从建立复杂构件的碳纤维复合材料层合板的阵列声场模型、优化损伤成像算法、构建智能/高效/实时化的结构健康监测成像系统、建立损伤定量评估标准、结合机器学习和数字孪生技术实施损伤诊断评估和寿命预测等方面进行了展望。 Abstract: Carbon fiber composites are widely used in aerospace and automotive industries due to the characteris-tics of low density, high elasticity, and better toughness. Due to the complexity and instability of the manufacturing process of carbon fiber composites and their vulnerability to environmental impact during service, it is likely to generate delamination, porosity, fiber wrinkle, and other types of damage. In this paper, the principles and characteristics of C-scan, phased array, air-coupled, optical fiber-ultrasound, and laser-ultrasonic testing based on body or guided waves, as well as the research status of these technologies for damage detection of carbon fiber compo-sites, are introduced respectively. The most representative imaging algorithms for damage diagnosis are shown, including total-focus imaging, 3D visualization imaging, tomography, reverse time migration imaging, and probability imaging method, these imaging methods can effectively realize various types of damage morphology in carbon fiber composites. The prospect is made from the following aspects: The establishment of an array acoustic field model of carbon fiber composite laminates, the optimization of damage imaging method, the construction of intelligent/efficient/real-time structural health monitoring imaging system, the establishment of damage quantitative evaluation criteria, and combination of machine learning and digital twin technology for damage diagnosis assessment and life prediction. -
表 1 检测碳纤维复合材料的线性换能器阵列参数
Table 1. Linear transducer array parameters for carbon fiber composites
表 2 用于碳纤维复合材料损伤的检测技术的比较
Table 2. Comparison of damage detection techniques for carbon fiber composites
Detection technique Wave type Damage type Feature C-scan Body wave Hole[25], delamination[37], impact damage[42],
debonding defect[43]Intuitive display and high detection efficiency Phased array Body wave Delamination[30, 35, 51], fiber wrinkle defect[32] Acoustic beam focusing, high detection accuracy, high detection sensitivity Guided wave Delamination[90], drill hole[59], multiple surface damage[63] Air-coupled Body wave Delamination[40], square hole[41], impact damage[42], debonding defect[43] Contactless, no coupling agent, no effect on material properties Guided wave Circular defect[69] Laser ultrasonic Body wave Circular defect[46], delamination[45] Long-distance, contactless, high-resolution, wide-range detection Guided wave Impact damage[70] Optical fiber ultrasonic Guided wave Impact damage[88] Anti-electromagnetic interference, corrosion resistant 表 3 三维图像重构的两种数据采集方式的优劣
Table 3. Advantages and disadvantages of two data acquisition methods for 3D image reconstruction
表 4 5种成像方法用于碳纤维复合材料损伤的优劣
Table 4. Advantages and disadvantages of five imaging methods for carbon fiber composite damage
Imaging method Wave type Advantage Disadvantage Application Total focus method Body wave Simple algorithm Artifacts Hole[51], fiber wrinkle defect[32] 3D visualization imaging Body wave 3D damage image Large amount of data, complex process Impact damage[110] Tomography Guided wave No media prior knowledge required Large amount of calculation Delamination[116] Reverse time migration Guided wave High accuracy Large amount of calculation and storage space Damage of thin plate of complex structure[133-134] Probability-based
diagnostic imagingGuided wave No media prior knowledge required Vulnerable to environmental impact Debonding damage[142-143] -
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