Q235焊接钢板受剪声发射时频特性分析

Q235钢板在工程中应用广泛,为了研究焊接对于Q235钢板性能的影响,开展了焊接试样和完整试样的受剪实验,利用数字声发射系统对实验过程的声发射信号进行实时采集。根据声发射计数率划分不同阶段,采用魏格纳-维尔分布,平滑伪魏格纳-维尔分布,对信号进行时频分析。实验结果表明:受剪实验中,焊接试样与完整试样的声发射特性明显不同,主要表现在受剪过程的各阶段中声发射信号能量集中的频带不同,弹性变形阶段信号时频带主要集中在80~100 k Hz附近;钢板塑性变形阶段时频带集中在100~140 k Hz范围内;焊缝塑性变形阶段,时频能量主要集中的频带范围在300~350 k Hz之间,部分能量较弱的信号分布在100 k Hz附近频段。

Time-frequency analysis of AE signals arisen from Q235 welded steel

Q235 steel is widely used in engineering, in order to study the welding effect on the properties of Q235 steel plate, the shear experiments of welded and complete samples are conducted by using a digital acoustic emission system to acquisit realtime acoustic emission signal. According to the counting rate of the signal, the signal is divided into different stages, then the Wigner Ville distribution WVD and the smoothed pseudo Wigner Ville distribution (SPWVD) are used to carry out the time-frequency analysis of the signal. The results show that the in shear experiments, the acoustic emission characteristics of the welded sample and the complete sample are very different, mainly in shear process the acoustic emission signal energies in different stages are concentrated in different frequency bands:in the elastic deformation period, the signal band is mainly concentrated in the vicinity of 80-100 kHz; in the plastic deformation period of steel plate, concentrated in 100-140 kHz range; in the plastic deformation period of weld joint, the time-frequency energy mainly concentrates in the frequency range of 300-350 kHz and part of weak energy signal distributed in the band near 100 kHz.