使用激光振动法检测飞机损伤检测

Commercial exploitation of lamb wave inspection has been restricted by weaknesses in detection methods. Structural damage can be identified clearly from locally increased in-plane and out-of-plane vibrations, by employing the non-contact technique of 3D Scanning Laser Vibrometry. This technique is quick, simple, and reliable, avoiding complex Lamb wave propagation studies, baseline measurements and signal post-processing.

介绍

Aircraft manufacturers, designers, and operators face many measurement and test challenges. New, large-capacity civil airframes which make better use of composite materials are being developed and will become more widespread. Also, new military structures show better performance by employing more structural complexity. End-users of these new aerospace structures call for high operational availability and lower life-cycle costs.

可以通过更广泛的损害设计概念和新材料的应用来实现这些目标，从而导致结构较轻，性能更好。亚博网站下载在开发这些新飞机的同时，现有的机队正在老化，必须维护。

已经考虑并执行了许多寿命延长计划。重新设计军用飞机以增加新的武器能力，并且民用结构正在从客运飞机转换为货轮。对于当前的飞机结构检查和维护技术，这些发展是一个巨大的挑战。

老化飞机结构需要大量的维护工作。在下一代飞机中的应用耐受概念和新材料的应用还需要定期检查，还需要更好，更可靠的结构健康监测，以确保安全和亚博网站下载延长的运营生活。

羔羊波的损坏检测

There are numerous technologies for automatic damage detection in aerospace structures.羔羊波检查是一种广泛使用的方法，基于引导超声波，即在有限培养基中传播的超声波数据包。

There are three major disadvantages related to conventional Lamb wave damage detection methods:

1. 用于损坏检测使用的当前信号处理和解释方法，使用信号参数，该参考基线数据代表“无损害”条件。这些参数可以受到除结构损伤以外的参数的影响，例如传感器之间的不良耦合与结构或温度变化。
2. Often associated with complex data interpretation, Lamb wave monitoring strategies need highly qualified NDT technicians for point-by-point field measurements. So, broad deployment is restricted by a lack of properly trained technicians and higher costs.
3. 需要大量的执行器/传感器传感器来监测大型结构。这是缓慢，劳动密集型且昂贵的。从物流的角度覆盖具有数千封粘合或嵌入式传感器的飞机是不切实际的。

3D扫描激光振动法

Laser vibrometers可以克服与羔羊波损伤检测方法相关的许多挑战。在图1中显示了非连接，PSV扫描激光振动仪到结构损伤检测中的应用。通过利用Polytec的PSV-3D扫描振动计，可以感觉到来自Polytec的PSV-3D扫描振动计的羊肉波，如图2所示。

The 3D Scanning Vibrometer covers the full optically accessible surface with a high density of sample points. The vibration vector is measured, including both out-of-plane and in-plane components at every sample point. These measurements are assembled into an intuitive 3D animated deflection shape.

在图3和4中，可以看到采用羔羊波监测的航空航天样品中检测到的损伤的示例。这些结果表明，可以通过局部增加的平面内振动幅度来识别结构损伤（例如，图3中的疲劳裂纹，以及图4中的分层。）和通过平面外振动幅度的衰减（例如，图3中的疲劳裂纹）。

结论

激光振动仪扫描可以揭示结构损伤及其严重性，例如分层区域和裂纹长度。整个结构上的简单轮廓图和羔羊波振幅的曲线足以观察到损坏的区域，并且不涉及未损坏的结构中的基线参考测量，检查结构中复杂的羔羊波传播的检查或信号后处理以提取损伤有关特征。

This technique is quick, straightforward, reliable and immune to environmental influences. We thank Professor Wieslaw Staszewski of Sheffield University for his work in this area.

图1。Experimental setup for Lamb wave damage detection using 3D Laser Scanning Vibrometry as receiver.

Figure 2.使用Polytec的PSV软件绘制的平面内和平面外羔羊波响应。

Figure 3.具有羔羊波的金属结构中的疲劳裂纹检测 - RMS振幅轮廓图，遍布疲劳裂纹的振幅轮廓：75 kHz的面内振动（上图）和325 kHz的平面振动（下）。

图4。Impact damage detection in composite structures with Lamb waves – amplitude contour map with amplitude profiles across delamination for 100 kHz in-plane vibration.

图5。测量设置：用于在碳纤维机翼部分上局部激发羔羊波的压电器。

图6。Full-field measurement with high spatial resolution on large components or complete aerospace structures.

此信息已从Polytec提供的材料中采购，审查和调整。亚博网站下载

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