YAG激光焊接脉冲能量作用效应的声发射特征参数表征

对304不锈钢进行脉冲激光焊接试验，基于激光热源与工件相互作用所释放的声发射信号，研究利用声发射事件的平均峰值-振铃计数特征分布图评估焊接稳定性的方法.结果表明，脉冲激光对材料的作用越稳定，平均峰值-振铃计数特征分布图的散点分布聚集性越好；脉冲激光对材料的作用稳定性越差，平均峰值-振铃计数特征分布图的散点分布越发散.激光脉冲峰值功率增加时，对应声发射事件平均峰值和振铃计数均随之增加，反映出振铃计数对峰值功率变化而引发的焊接稳定性变化更为敏感.因此平均峰值-振铃计数特征分布图能够较为准确地表征激光焊接过程稳定性.

Characterization of impact effect of pulse energy based on feature parameters of acoustic emission signals detected in YAG laser welding

Pulse YAG laser welding was used for the welding of stainless steel. The stability of welding process was studied based on the structure-borne acoustic emission (AE) signals released by the interaction effect of laser heat source and materials researched, which was characterized by scatters feature distribution of average peak-AE count. The result showed that the scatters distribution aggregation of average peak-AE count feature distribution was better as the process of pulse laser welding was stable. Conversely, the scatters distribution aggregation was more divergent. With the increase of laser pulse peak power, the average peak and AE counts of laser pulse AE event increased, which indicated that the AE count was more sensitive to the stability fluctuation of welding process induced by the laser pulse peak power. Consequently, it was possible to characterize the stability of laser welding process by the methodology of scatters feature distribution of average peak-AE count.