Study On Acoustic Emission Localization Of Concrete Using Corrected Velocity

As the most widely used building materials in the field of civil engineering,concrete in the service stage with cracks is a commonphenomenon.However,when the crack extended to a certain extent,it will bring a series of problems such as leakage,corrosion,seriously affect the structural safety and durability.Acoustic emission detection method as a nondestructive technique with alarm,real-time continuous monitoring of structural safety and limit function,especially by acoustic emission technology can get the relevant materials of the internal damage distribution information.In practical engineering applications,it is the ultimate goal of acoustic emission testing to locate and monitor the location and development of structural defects and to take corresponding remedial measures.As a number of concrete composite material has its own defects,inevitably,the wave propagation in the inhomogeneous material in the concrete will have a certain degree of attenuation,leading to constant velocity wave propagation in concrete is not,has a certain function of wave velocity and propagation distance.The current location of acoustic emission monitoring system are set as velocity values of acoustic emission damage location,can not be done on the variation of the velocity,resulting in concrete homogeneous material damage localization results of large deviation.Research shows that the concrete water cement ratio,aggregate size,curing age is the main factor affecting the acoustic emission signal attenuation,the preparation of different ratio of concrete block,mainly the following aspects of work:(1)The effect of aggregate size and water cement ratio on the compressive strength and acoustic emission characteristics of concrete under compressive loading was studied by the means of concrete cube compression test.(2)The effect of water cement ratio,aggregate size and curing age on the wave velocity is studied,and the variation law of wave velocity with distance is determined.(3)The positioning principle of 3D prepared AE location software exhaustive method based on acoustic emission,and the wave function into the program,through the acoustic emission source of 3D positioning test comparison of wave velocity before and after the correction of acoustic emission location precision lead cutting simulation,verify the feasibility of the concrete material for the velocity correction of acoustic emission with high accurate positioning and effective.The experimental results show that the location algorithm based on the 3D enumeration method combining the modified acoustic emission velocity of concrete damage can accurately position monitoring,can reflect the damage of concrete cracks and make prediction and assessment.