Figure 1 - available via license: Creative Commons Attribution 3.0 Unported
Content may be subject to copyright.
Value dynamics of index D depending on speed in the contacting pair with the lubricant "Industrial oil I-20". The figure shows a stable existing trend of acoustic emission signal increasing together with the angular speed increase. Herewith the higher the pressure in the contacting pair, the more intensive the increase in index D. It bears evidence about degradation of the contacting pair friction conditions, pressing lubrication out of the contact area and transfer from volumetric friction to dry friction. Figure 2 demonstrates the character of acoustic emission value change described by index D for a sequence of pressure values in a contacting pair by constant angular speeds. Similar to the angular speed parameter influence, the trend reveals that the acoustic emission signal value corresponding to the friction factor should change depending on pressure in the contacting pair. Transfer to the dry friction condition by high speeds happens already according to low pressure values,
Source publication
An experiment was conducted to confirm the reliability of the evaluation of the technical condition of transmission elements during operation in terms of the magnitude and nature of the acoustic emission signal, while completing the negative effect of the artificial environment on the durability of the transmission elements. Thus, the results of th...
Context in source publication
Context 1
... the experiments a relative index D is measured that is proportional to the value of acoustic emission appearing in the friction couple "counterbody -plate" and to the index of friction in the couple [2,8,10]. Figure 1 shows the changing in the signal value of acoustic emission friction described by the index D for a sequence row of angular speeds by constant pressures in a contacting pair. Similar to the angular speed parameter influence, the trend reveals that the acoustic emission signal value corresponding to the friction factor should change depending on pressure in the contacting pair. ...
Similar publications
The paper reports results of the study on the possibility of using the acoustic emission method in diagnosing fatigue and corrosion damage in steel elements of the cable way support towers. The assessment of the sensitivity of the structure to the recorded destructive processes is based on the structural damage classification method using the patte...
In order to study the interface bond-slip failure mechanism of concrete-filled steel tube (CFST). Acoustic emission (AE) test was carried out on the push-out test of 9 CFST specimens by using AE monitoring system. AE impact counting, energy release and frequency spectrum characteristics were obtained. The test results indicated that the load-slip c...
Inversion of hypocenters is the first and most fundamental step in the study of seismic activities. It requires solving the nonlinear relation between the travel time and hypocenter locations, which is heavily dependent on the knowledge of the medium properties, most importantly the velocity structure. In this study, we prove that machine learning...
The failure of rail infrastructure components can have wide and far-reaching consequences across the rail network. To ensure failure risk is minimised, accurate, real-time monitoring of railway critical assets is required. Techniques used to monitor the network must have minimal, or ideally no impact on the capacity and availability of the network....
In the present work, the Brazilian tests for six sandstone samples were carried out. The acoustic emission (AE) method was applied to analyze the characteristics of the crack propagating mode and further to classify the cracking mode during the whole sandstone lump Brazilian splitting process. The study results showed that the AE event produced dur...
Citations
... Therefore, the acoustic signal excited in the layered coal-rock mass is the superposition of its own (resonant) elastic vibration in each individual layer. In the process of coal mining, the cutting mechanism of the running mining equipment is used as the source of acoustic vibration [20]. Taking the working face as an example, the acoustic vibration excites near the working face, with propagation to the deep coal body and the sound wave passing through the medium with variable parameters. ...
... Therefore, the acoustic signal excited in the layered coal-rock mass is the superposition of its own (resonant) elastic vibration in each individual layer. In the process of coal mining, the cu ing mechanism of the running mining equipment is used as the source of acoustic vibration [20]. Taking the working face as an example, the acoustic vibration excites near the working face, with propagation to the deep coal body and the sound wave passing through the medium with variable parameters. ...
With the increase in coal mining depth, the stress and strain state of coal and rock mass affects the formation of dangerous zones of dynamic phenomena. In order to study the relationship between the frequency spectrum characteristics of artificial acoustic signals and the stress state of coal and gas pressure, a test device and system that can generate acoustic signals by mechanical vibration excitation are developed by using the design idea of the unit module. Firstly, the basic mechanical parameters of coal under uniaxial compression are analyzed. On this basis, we use the test device to study the qualitative and quantitative relationships between the relative stress coefficient K value of the coal body and the axial loading stress, whether it contains gas, and the mechanical vibration force. The test results show that when the gas-containing coal and the gas-free coal are subjected to the same external mechanical vibration knocking force to stimulate the artificial acoustic signal test, the relative stress coefficient K value increases first and then decreases with the increase in axial loading stress. The relationship between the relative stress coefficient K and the axial loading stress σ can be expressed in the form of exponential function K=e−Cσ. When the axial loading stress and the external mechanical vibration force are both fixed values, the relative stress coefficient K value of the coal body with gas is smaller than that without gas. When the axial loading stress and gas-bearing pressure of the coal body are both fixed values, the relative stress coefficient K value decreases with the increase in the impact force of the external mechanical vibration. This experimental study can provide a reference for the identification and prediction of dynamic disasters based on artificial acoustic signals.
... Unit setting up and software updating can be performed through USB interface in the unit with the help of a computer or remotely through the onboard computing system. For data storing, a power independent SD-card is installed in the unit [13,14]. ...
This article presents the results of multiple-conditions wear-resistance tests for the antifriction bearings that are used in a milling tool. The test was performed on a one-fifth milling tool model. The tests were divided into three stages. The first testing stage included tests of a model with a new undamaged bearing. The second stage included tests of a model with a bearing that is worn out by approximately 50%. The third stage included tests of a model with a completely worn out antifriction bearing. Along with vibroacoustic tests, we measured the temperatures of the tested triboelement. In this article, we provide amplitude-frequency values of vibroacoustic signals recorded during the tests of a model with an undamaged antifriction bearing, a bearing with 50% worn-out extent, and 100% worn-out bearing. Appropriate resistance levels of complex machine elements cannot be achieved without systems of triboelements condition control. We suggest attaching temperature and vibroacoustic sensors to the critical elements of a peat winning machine that provide data for integral analysis of triboelemets condition and prevent failures when damage is recorded. Integral analysis of the technical condition of the main triboelements will allow performing the highly precise prognosis of the remaining life of a peat-winning machine, thus preventing failures in peat mining seasons.
... For the convenience of service, improving the quality of this service, mechanizing production and reducing economic costs during maintenance and repair of mining machines involved in carrying out basic and auxiliary works in the implementation of mining technologies, work is underway to create mobile and autonomous technical means for carrying out delivery work, storage, regeneration and collection of used oils and lubricants as part of scheduled maintenance and repair work. However, when performing lubricating and filling operations with the help of mobile workshops, problems arise associated with forcing grease into the system due to the inability to create the necessary pressure with domestic metering pumps [16,17]. ...
Significant portion of the annual calendar fund-time work of mining excavators spent on maintaining its working condition by carrying out preventive and repair regulatory activities and recovery in the event of emergency failures and maintenance and repair expenses constitute a significant proportion of the cost of excavation of mining rock. To assess the effectiveness of machinery a non-standard indicator, the coefficient of technical readiness, applied which does not have a single assessment methodology. At the present stage of machinery development, existing quarry dispatching systems allow you to allocate any of its elements from the fund-time of mining excavators: productive time, time spent in repair and maintenance and also classify other time costs of a particular machine which allowed an appropriate analysis. Analysis showed that at the current organization of MaR (maintenance and repair) there is significant potential to reduce repair impacts, as well as to ensure a reduction in the cost of routine maintenance, to remove maintenance and repair measures from the category of costly ones, at least for self-sufficiency without compromising the quality of these works and the reliability of the excavator as a whole.
Development and application of digital technologies at the stage of new model design is highly relevant. Manufacture of a testbed vehicle and its full-scale pilot testing is impossible for Russian manufacturers of mining excavators due to a high cost of a prototype and a lack of special testing grounds. In order to reduce the risks of machine builders as vehicle manufacturer and those of MPPs as users of the prototype excavator, it is necessary to introduce and develop the digital twin technology at the stage of designing new models. A general reference point in development of the digital twin of a mining excavator is minimizing human input. Due to integration of works by stages of creation of the digital twin in a form of an information diagnostic system, there is a possibility to manage the life cycle of the product and optimize MRO with accounts of actual conditions and operating modes.
While manufacturing and exploitation of different materials, there could be observed complex physicochemical processes of interaction between their individual components and these components with the environment. Revealing such mechanisms helps to understand their distinct features and optimize technological processes of manufacturing materials with certain characteristics. The solution could be based on interpretation of results of acoustic emission (AE) tests from the perspective of multilevel kinetic model of AE of heterogeneous materials. The article describes the research, the essence of which was to identify systematic changes in the values of the parameters of the AE coefficients included in the model when changing various technological and operational factors on the basis of their operational assessment based on the results of acoustic emission tests.
The method of acoustic emission (AE) and the information-kinetic approach to AE diagnostics are identified as the most promising from the point of view of observing the process of growth of damage and optimization of production technologies. Based on a multi-level model of the time dependence of AE parameters, estimation of elastic homogeneous fracture intensity parameters of representative structural elements of a product and universal strength nanoconstants, the approach combines the traditional experimental way of resource estimation and kinetic representations of fracture. This allows to separate the effect of macro- and nano-factors on the AE of the material, variously related to the strength and acoustic emission activity of the material. A multilevel model and an informational-kinetic approach to acoustic emission diagnostics are described, combining nano-, micro- and macro-factors affecting acoustic emission activity, reliability of technical objects and methods for assessing their resource. On the example of a welded pressure vessel, the implementation of the method of its nano-diagnosis is considered. The possibility of effective resource estimation of various technical objects based on the information-kinetic approach to their acoustic emission diagnostics is shown. As a methodological basis, a multilevel model of the time dependences of the AE parameters is taken, which describes their behavior under conditions of strength and metrological heterogeneity.
As a result of the studies, the possibility of assessing the state of the working surfaces of mining machines, in particular bearing assemblies as a whole without disassembling the gearbox, is confirmed. An innovative solution in this matter is to ensure the delivery of the lubricator to tribolcoupling through the channels of the lubrication system, according to its state, determined by the size of the acoustic signal of the ultrasonic range in the friction pair.
