AE Signal Identification of Offshore Platform Tubular Joints Crack Propagation Based on Wavelet Energy Coefficient
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摘要: 提出一种海洋平台管节点疲劳裂纹扩展状况识别方法，将小波分配尺度谱和小波能量系数应用于海洋结构件的典型疲劳裂纹扩展和断裂声发射信号的特征提取，提高了尺度图像的聚集性，排除了噪声干扰；通过海洋平台典型管节点模型断裂试验，运用PXWAE声发射检测仪对试件断裂全过程进行监测，成功提取到裂纹扩展和断裂过程中的声发射信号。结果表明，小波能量系数的变化与裂纹发展状态的变化呈现良好的一致性，能够准确、直观、清晰地表征出裂纹扩展不同阶段AE信号的特征，能够有效应用于海洋平台管节点疲劳损伤状态的在线实时监测和故障诊断。Abstract: An identification method of the offshore platform tubular joints fatigue crack propagation was proposed. Wavelet allocation scalogram and wavelet energy coefficient method were applied for the feature extraction of acoustic emission(AE) signal of marine structures typical fatigue crack propagation and fracture at the same time. The method could improve the aggregation of scalogram by excluding noise. By making the typical tubular joints model fracture experiments of the offshore platforms and using PXWAE AE detector to monitor the whole process of the specimen fracture, the paper successfully extracted the AE signals of crack propagation and fracture process. The analysis results demonstrated that the variation of wavelet energy coefficient and the change of crack propagation state were in a good consistency and could characterize the AE signals characteristics of different stages of crack propagation accurately, intuitively, and clearly. It could be used effectively in online real-time monitoring and fault diagnosis of offshore platform tubular joints fatigue crack.
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