由于汽车起重机存在典型焊接缺陷声发射信号获取困难，缺陷识别方法不成熟等诸多问题，因此通过添加附属焊接缺陷试块的方式模拟了关键结构件局部焊缝的破坏过程，获取了该破坏过程的典型声发射数据样本，对信号衰减进行了测试，并结合声发射特征参数及频谱特征分析方法对典型声发射源进行了分析。结果表明：采用上述方式后，声发射技术能够实现焊接缺陷源的准确定位；持续时间、频率质心及峰值频率等特征，指标能够对损伤源与噪声源进行准确划分。

Structural welding defects are vital safety hidden troubles to the crane, and acoustic emission(AE) technology can be used to monitor the defect changing process. Because of the complex and changeable application conditions for the truck crane, it is difficult to obtain the real AE signals of welding defect and the recognizing methods are not mature. Through adding ancillary testing specimens with welding defects to the principal structure, the breakage process in welded seam of structure was simulated, and the typical AE data during damage process were collected. The signal attenuation was tested, and in combination with characteristic parameter analysis methods and spectral characteristic analysis methods, the typical AE signals were analyzed. The result shows that AE technology can be used well for the accurate positioning of welding defects; and some characteristic parameters such as duration time, frequency centroid and peak frequency can be used to classify the defect signals and the noise.