Study on the breaking process and damage characteristics of abrasive water jet impacting concrete based on acoustic emission.

• ·Acoustic emission signals characteristics of AWJ impacting concrete is studied. • ·Correlation between AE signals and development of erosion hole is studied. • ·The damage of concrete is defined based on the ultrasonic velocity is established. • ·Damage distribution of concrete impacted by AWJ. The breaking process and damage distribution characteristics of concrete are the theoretical basis for improving the quality and safety of concrete impacted by abrasive water jet (AWJ) technology. Therefore, the process of AWJ impacting concrete is monitored online based on acoustic emission (AE) technology in this paper. The results show that the AE signals of AWJ impacting concrete have two peaks in frequency domain, the low frequency signals are generated by AWJ and the high frequency signals are generated by concrete breaking. The autoregressive (AR) model is used to estimate the power spectrum of AE signals. The variations of AWJ signals and concrete crushing signals in the impact process are analyzed based on the power of AE signal defined by the area under the power spectral density (PSD) curve. Through monitoring the development process of erosion hole inside the transparent materials impacted by AWJ, it is verified that the power of the concrete crushing signals after the formation of the erosion hole can reflect the penetration rate well. In addition, the damage characteristics of concrete specimens impacted by AWJ are studied in this paper by measuring the transverse ultrasonic velocity of the specimens before and after impact. [ABSTRACT FROM AUTHOR]