基于相位差时延估计法的岩石声发射源定位研究

针对岩石力学试验声发射时差定位算法中时延估计精度受诸多不确定因素的影响问题，提出全相位相位差法时延估计，通过小波分解与全相位频谱分析相结合求解相位差得到声发射信号的时延估计。利用小波分解找到不同传感器接收到的声发射信号中的同一主频的子带信号；对这些同一主频的子带信号分别做全相位频谱分析，得到每个子带信号中间样点的相位，再根据相位差与时间差的关系求出声发射信号到达不同传感器之间的时间差；进而利用时差定位法反演声发射源，实现了声发射源更精确的定位。在花岗岩（50 mm×100 mm×50 mm）上进行断铅试验，选取10个测点，经声发射监测验证结果表明，该时延估计方法能有效地减小声发射源定位的误差，提高声发射源的定位精度，平均绝对误差比美国PCI-2型声发射仪器定位结果提高约3 mm，该方法为反演声发射源提供了一种有效途径。

Time delay estimation and acoustic emission source location of rock based on phase difference

Lots of uncertain factors affect the time delay estimation precision of time-difference location method in rock acoustic estimation(AE) experiments. Aiming at this problem, the all phase phase-difference time delay estimation method is proposed. Time delay of AE signal is deduced through the phase-difference obtained by combining wavelet decomposition and all phase frequency analysis. AE sub-band signals with the same dominant frequency from different sensors are found with wavelet decomposition. Then the phases of middle sample of every sub-band signal are obtained with all phase frequency analysis method for those chosen sub-band signals, and the time-differences of AE signals’ reaching different sensors are computed according to the relationship between phase-difference and time-difference. Finally, the AE source is located by the method of time-difference location. Experiments are conducted on a 50 mm×100 mm×50 mm granite stone, and AE source is generated by broken lead at ten different points. Under the lab environment, the results from the proposed AE location method indicate that using phase-difference based on wavelet transform and all phase frequency analysis can effectively improve the accuracy of location of AE source. Compared to the results obtained by the PCI-2 acoustic emission instrument, the absolute error reduces by about 3 mm, so as to provide an effective way for AE source inversion.