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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利用感应热成像技术对飞机制动部件的微裂纹进行热模式对比诊断


往复冲击载荷会导致飞机制动系统中运动链表面发生塑性变形。结果，这会导致疲劳和各种复杂的自然损伤。由于表面状况复杂且损伤共存，利用传统的热成像检测方法诊断微裂纹极其困难。在本文中，提出了利用涡流脉冲热成像技术进行微弱热信号检测的热图案对比方法。在此过程中，提取和随后的分离区分了缺陷区域和非缺陷区域之间的热空间瞬态模式的最大值。具体来说，建立连续的光流来进行热扩散的投影。这直接获得了捕获热传播特性的好处。它使我们能够构建局部和全局热空间模式之间连接的运动上下文。构建主成分分析以进一步挖掘空间瞬态模式，以提高微裂纹检测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。