Reciprocating impact load leads to plastic deformation on the surface of the kinematic chains in an aircraft brake system. As a result, this causes fatigue and various complex natural damages. Due to the complex surface conditions and the coexistence damages, it is extremely difficult to diagnose microcracks by using conventional thermography inspection methods. In this paper, the thermal pattern contrast method is proposed for weak thermal signal detection using eddy current pulsed thermography. In this process, the extraction and subsequent separation differentiate a maximum of the thermal spatial-transient pattern between defect and nondefect areas. Specifically, a successive optical flow is established to conduct a projection of the thermal diffusion. This directly gains the benefits of capturing the thermal propagation characteristics. It enables us to build the motion context connected between the local and the global thermal spatial pattern. Principal component analysis is constructed to further mine the spatial-transient patterns to enhance the detectability and sensitivity in microcrack detection. Finally, experimental studies have been conducted on an artificial crack in a steel sample and on natural fatigue cracks in aircraft brake components in order to validate the proposed method.

中文翻译：

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感应热成像技术对飞机制动部件微裂纹的热模式对比诊断

往复的冲击载荷导致飞机制动系统中的运动链表面发生塑性变形。结果，这导致疲劳和各种复杂的自然损坏。由于复杂的表面条件和共存的损坏，使用传统的热像仪检查方法来诊断微裂纹是极其困难的。针对涡流脉冲热像仪检测弱热信号的问题，提出了一种热模式对比方法。在该过程中，提取和随后的分离将缺陷和非缺陷区域之间的最大热空间瞬态图案区分开。具体地，建立连续的光流以进行热扩散的投影。这直接获得了捕获热传播特性的好处。它使我们能够建立连接局部和全局热空间模式之间的运动环境。构建主成分分析以进一步挖掘空间瞬态模式，以增强微裂纹检测中的可检测性和灵敏度。最后，对钢样品中的人工裂纹和飞机制动器部件中的自然疲劳裂纹进行了实验研究，以验证所提出的方法。