Advanced Magnetic Barkhausen Noise for Residual Stress Measurement in Aircraft Landing Gear

残余应力可导致飞机起落架部件的灾难性失效。目前，还没有可靠的无损检测技术，用于在不去除油漆的情况下对在役构件进行残余应力测量。X射线衍射（XRD）需要去除油漆和金属镀层，然后蚀刻基底金属。当前的磁巴克豪森噪声（MBN）技术仅需要去除油漆。然而，虽然MBN已经被用于仅使用单个测量参数来检测飞机起落架中的高残余应力区域，但是已经发现其当前形式是不可靠的。最近的进展，在控制所产生的磁通量的激励场用于产生巴克豪森噪声havemonized提高测量的可重复性，以及提供额外的表征相对磁性能的潜力。此外，相互正交场激励的发展具有提供组件的各向异性磁性能的快速评估的前景，这可能与其应力状态相关。信号分析技术也得到了发展，包括MBN能量、巴克豪森噪声包络和脉冲高度分布的评估。需要进一步开发MBN技术，以识别和补偿可能影响测量结果的重要参数。例子包括油漆厚度变化的影响，喷丸处理引起的压缩表面应力状态的变化和钢的塑性变形的影响。还需要探针设计优化，以适应独特的几何形状，例如小曲率半径。进步的理解和补偿的参数，影响MBN信号的产生是所提出的工作的一部分。此外，将开发用于残余应力测量的先进MBN信号分析方法。 有限元模型将用于探针设计和预测塑性变形飞机起落架中残余应变场的大小和方向。拟议的工作是与赛峰着陆系统公司合作，位于安大略阿贾克斯，生产飞机起落架。

Residual stress can lead to catastrophic failure of aircraft landing gear components. Currently, there is no reliable non-destructive inspection technology for residual stress measurement on in-service components without paint removal. X-Ray diffraction (XRD) requires both paint and metal plating removal, followed by etching of the base metal. Current Magnetic Barkhausen noise (MBN) technology only requires paint removal. However, while MBN has been employed to detect areas of high residual stress in aircraft landing gear using only a single measurement parameter, it has been found to be unreliable in its current form. Recent advances in control of the magnetic flux generated by the excitation field used to generate Barkhausen noise havedemonstrated a potential for improving measurement repeatability, as well as providing additional characterization of relative magnetic properties. Furthermore, development of mutually orthogonal field excitation has prospects to provide rapid evaluation of a component's anisotropic magnetic properties, which may be correlated with its stress state. Signal analysis techniques have also been advanced, including evaluation of MBN energy, Barkhausen noise envelope and pulse height distribution. Further development of MBN technology is required to identify and compensate for significant parameters that may affect measurement outcomes. Examples include effects of paint thickness variation, variability in compressive surface stress state induced by shot peening and the effects of plastic deformation in steel. Probe designoptimization is also required, in order to accommodate unique geometries, such as tight curvature radii. Advancement in the understanding and compensation for parameters that affect MBN signal generation is part of the proposed work. In addition, advanced MBN signal analysis methodology for residual stress measurement will be developed. Finite element modelling will be used for probe design and prediction of magnitude and direction of residual strain fields in plastically deformed aircraft landing gear. The proposed work is in collaboration with Safran Landing Systems Inc., located in Ajax Ontario that manufactures aircraft landing gear.