Acoustic Emission Testing Technology Research Articles

Enhancing Preamplifier Design for Acoustic Emission Detection Instrument

With the development of the industry, the safety of pressure vessels is crucial for both production and personnel safety. The application of acoustic emission testing technology as a dynamic non-destructive testing method in the detection of pressure vessels is becoming increasingly prevalent. This paper presents the design of a low-frequency acoustic emission preamplifier with a frequency range of 30KHz to 200KHz and a gain of 20dB. The preamplifier is composed of amplification circuits, power supply circuits, and filtering components. By utilizing the PXR04 series high-sensitivity resonant acoustic emission sensor and Texas Instruments' OPA333 operational amplifier, along with a clever power supply design, effective signal amplification and system stability are ensured. Experimental results validate the correctness of the design, providing a feasible and effective solution for enhancing the performance of acoustic emission testing equipment.

Exploration and Application of Acoustic Emission Detection Technology in Leakage Detection of the Bottom Plate of Crude Oil Metal Storage Tanks

The use of acoustic emission detection technology can conduct online and non-stop detection and evaluation of crude oil metal storage tanks, achieving the integrity detection and evaluation of storage tanks. In order to explore the applicability of acoustic emission detection technology in the leakage detection of the bottom plate of crude oil metal storage tanks, this project carried out online acoustic emission detection of crude oil metal storage tanks, magnetic flux leakage detection after tank opening and cleaning, and compared and analyzed the results of two detection technologies. The adaptability of online acoustic emission detection technology was analyzed and explored. It was found that acoustic emission technology can qualitatively evaluate the corrosion of tank bottom plates, but cannot accurately locate corrosion defects. For tanks with severe corrosion that require maintenance, it is still necessary to open the tank and use magnetic flux leakage and other detection techniques to determine the location of defects. Through comparative analysis of acoustic emission testing technology and magnetic flux leakage testing technology, the results obtained from acoustic emission testing technology are conservative compared to the actual results. It is recommended to upgrade the evaluation of corrosion degree for the acoustic emission evaluation results of crude oil metal storage tanks.

Experimental Study On 3D Acoustic Emission Source Location of Concrete Based On Sparse Least-Squares Support Vector Regression

In order to further prove the effectiveness of the sparse least-squares support vector regression (S-LS-SVR) method in damage detection, the authors used the S-LS-SVR model to locate actual damage sources of concrete. The data from acoustic emission testing (AE) are generated and filtered by the pullout test of reinforcement in concrete, and the three-dimensional coordinates of real-time damage sources in the failure process are provided through the model. The S-LS-SVR method is compared with the Newton iterative method and improved exhaustive method for positioning speed, positioning data utilization, and positioning accuracy. The results show that S-LS-SVR is superior to the two other time difference of arrival–based positioning methods in positioning speed, positioning data utilization, and positioning accuracy (data utilization is slightly lower than the improved exhaustive method). The location method based on S-LS-SVR provides the possibility for the application of AE technology in intelligent damage location of bridges, dams, and other service structures.

Acoustic emission source localization method for high-speed train bogie

Bogie is one of the most critical parts of high-speed train and is directly related to the operation quality and safety of the train. However, currently no dynamic non-destructive testing method exists for real-time monitoring. Therefore, this paper proposes a new damage localization method for high-speed train bogie dynamic testing. The acoustic emission testing technology is applied to test the vulnerable welding parts of the bogie with time reversal localization method. Firstly, the bogie welding parts structure model based on finite element software is established. Then an acoustic emission damage signal is sent from the model and the acoustic emission source signal is received by the preset acoustic emission sensor. And the accurate localization of damage is achieved by dealing with the received signal according to the time reversal focusing principle and imaging the acoustic emission source. The simulation experiments show that the proposed method can accurately find the damaged localization. And finally, the method has been verified through experiment, and the results show it can effectively improve signal energy of the damage source, and the position of the damage source can be shown accurately through signal reconstruction and localization in the detection area.

The Acoustic Emission Testing Technology on Large Crane Structure Damage

The Acoustic Emission testing application on Crane steel structure is greatly limited, because of the factors such as the random transmission path of sound wave, the influence of dynamic load noise and the discontinuity of structure. In this paper, the feasibility of Acoustic Emission detection for crane structure damage is discussed from two aspects: mechanism test and field detection. Based on the analysis of the whole test process, when lifting heavy objects and braking, the metal structure is subjected to the instantaneous gravity load of tens of tons, so that a large number of AE signals are collected by various monitoring sensors. It mainly includes active defect damage, mechanical vibration, structural friction and electrical noise, etc. At this time, the effective defect expansion signal is compared with the noise signal. However, in the load maintenance phase, the noise signal disappears or drops to a very low level. At this point, if a sensor still collects a strong active AE signal, it is highly likely that there is a damage source in this area. Compared with the traditional mechanical properties of materials, AE characteristic parameters, such as amplitude, ringing count and energy count, can reflect the microscopic damage changes of materials under load in a more detailed way. By summing up the distribution range of AE parameters corresponding to different damage mechanisms and typical signal characteristics, such as the double peaks phenomenon in the material yield stage, it can provide a scientific foundation for the application of AET in the metal structure damage of large lifting machinery.

Study on the Cracking Time in Low-stress Precision Cropping Based on Acoustic Emission Technology

The high-speed centrifuge and low-stress precision cropping is the technology which makes use of the stress concentration effect of the prefabricated V-shaped groove on the surface of the metal bar and relies on the expansion of the crack to achieve precision cropping. This paper applies the acoustic emission testing technology to monitor the entire process of low-stress precision cropping in order to solve the problem that the cracking time of V-shaped groove tip cannot be precisely determined during the low-stress cropping. It is concluded that the acoustic emission signal can be used to describe the crack damage process of V-shaped groove tip, providing better cross-section quality. Based on this, the cracking time of V-shaped groove tip is further determined, which better meets the requirements of low-stress precision cropping.

Анализ качества тестов при сертификации специалистов по акустико-эмиссионному методу контроля объектов железнодорожного транспорта

The results of qualification exams during specialist certification on acoustic emission nondestructive testing of railway objects are analyzed. The correspondence of task test difficulty with the level of specialist preparedness for certification is considered using the Rush method. Analysis of test results in specialist certification has shown:
 - the presence of the deviation in the distribution of test task difficulty level histograms from the uniform law, especially for special exam tests, that requires the elimination of the tasks with very low and very high difficulty level logits, as well as increasing the number of the tasks with the minimum function of task test difficulty logit;
 - the necessity of training intensification in the test topics corresponding to minimum specialist preparedness logits. 
 The obtained results are the bases for following analyses of the test task difficulty; the reasons of insufficient learning topic tasks with a low percentage of answer; making the possible adjustments in the consulting sessions, as well as the content and form of the test. 
 To exclude the test bias, the interview with certified specialist is carried out in examination center allowing specifying whether the specialist knows the basic concepts and has acoustic emission testing technology skills.
 In general the performed analysis showed a high preparedness degree for most specialists due to regular training and at least a year work experience on acoustic emission testing.

Crack Analysis of Multi-plate Intersection WeldedStructurein Port MachineryUsing Finite Element Stress Calculation andAcoustic Emission Testing

Crack is the main inducement of failure accidents in welded structures of port machinery. Taking actual engineering problems occurred in a coal wharf as a case where a stacker reclaimer altered its local structure (bucket wheel changed to be chute) and then cracks appeared on the Slew deck with pylon after half a year. Using the finite element simulation combined with acoustic emission testing, the stress concentration and crack active status of the multi-plate intersection welded structure were inspected, which aimed at monitoring the development trend of the cracks and finding out reasons. Finite element stress calculation method adopts Solidworks, ANSYS and Hypermesh software co-simulation to explore the effects of mesh type and density on the stress calculation results of the Slew deck with pylon structure, and to analyze the stress distribution of the multi-plate intersection shell structures. According to the analysis results, this paper infers the reasons for crack propagation. Combined with the regular monitoring of acoustic emission testing technology on the active state of cracks and the intensity of expansion, the influences on the apparatus are deduced by the crack states of the bucket wheel reclaimer operations under different working conditions. And then put forward measures for a whole reasonable structure of the rectification and crack repair plans. The results of the research show that: 1) The maximum stress value following the change decreases slightly，which indicates that structure change is not the direct reason for cracking, instead, it is the initial structure design problems; 2) The imbalance torque produced in the boom hinge point after the change is the direct reason for causing cracks; 3) The proposed repairing scheme significantly reduces the stress at the cracks, and improves the fatigue strength. Finite element simulation combined with acoustic emission testing method provides effective means for analysis and prediction of cracks occurred in multi-plate intersection welded structure of port machinery.

Quality Testing of the Chrome Coating Based on Acoustic Emission Technology

A assessment method on quality detected system was developed on cylinders inner wall coating through the hydraulic radial expansive load system and acoustic emission testing technology,. Put double probes linear position principle and uniform motion of load system together, and make curved positioning come true based on the technical principle of locating acoustic emission source. The disadvantage was solved that double probes can’t make acoustic emission source planar positioning. The result showed that this system can provide a precise identification and location; it has fast testing velocity and portable device.