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中文核心期刊

利用错频激励的不锈钢疲劳损伤非线性超声检测

Nonlinear ultrasonic testing for fatigue damage in stainless steel using frequency-mismatched excitation

  • 摘要: 材料或构件的疲劳损伤影响其服役安全, 传统线性超声技术难以检测出小于波长的微裂纹, 非线性超声对微损伤更加敏感, 但存在设备复杂、操作严格等问题, 限制了应用场景及使用效率。为此利用简易的超声脉冲回波实验系统, 引入错频激励模式进行非线性超声边带峰值计数实验, 探究检测和评价疲劳损伤的可行性。制备了6块不同疲劳程度的不锈钢试块, 采用所提方法对不同等级的疲劳裂纹进行检测和评价。研究结果表明, 基于错频激励模式的非线性边带峰值计数指标随疲劳裂纹的扩展而增大, 呈现出强线性相关性; 相比于正常激励模式受系统非线性和人工干扰的影响小, 具有更好的鲁棒性和可靠性。所提检测方法兼具线性超声操作简易和非线性超声技术灵敏度高的优点。

     

    Abstract: Fatigue damage of materials or components affects their reliability. Traditional linear ultrasonic techniques struggle to detect micro-cracks smaller than the wavelength, while nonlinear ultrasonics are more sensitive to micro-damage. However, current nonlinear ultrasonic methods face problems such as complex equipment and strict operation requirements, which limit their application scenarios and efficiency. This paper proposes a simple approach for fatigue damage inspection using the pulse-echo experimental system. The frequency-mismatched excitation mode is introduced to perform the nonlinear sideband peak count technique. Six stainless steel test blocks with different degrees of fatigue are fabricated, and the fatigue cracks are detected and evaluated using the designed experiments to verify the effectiveness and accuracy of the proposed method. The results show that the sideband peak count-index variations have a strong correlation with the fatigue crack length, and the varying degree of damage can be effectively and easily detected by the proposed method. Compared with normal excitation modes, it is less affected by system nonlinearity and artificial interference, showing better robustness and reliability. The proposed detection method combines the advantages of simple operation of linear ultrasonic and high sensitivity of nonlinear ultrasonic techniques.

     

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