Energy Distribution Law Research Articles

The energy dissipation topology and characteristics of GaInSn liquid metal and ZnO resistors based on high-voltage DC circuit breakers

High voltage direct current (HVDC) circuit breakers play a very crucial role in HVDC transmission systems. Energy dissipation circuit branches are the main part of the HVDC breaker. The volume and size of energy dissipation branches are the bottlenecks of the HVDC breaker, and the existing energy dissipation schemes can not meet the lightweight requirements. In this work, a combined energy dissipation scheme based on gallium indium tin (GaInSn) liquid metal and ZnO resistors is proposed for the energy dissipation branch of a circuit breaker. Firstly, the self-shrinking of GaInSn liquid metal mechanism is analyzed and the energy dissipation characteristics at different stages are investigated. The variation patterns of short circuit current, arc voltage, resistance and other parameters in the process of liquid metal arcing and energy dissipation are obtained. Secondly, the circuit model of liquid metal in arcing and energy dissipation process is established. The equivalent nonlinear time-varying conductance of the arcing process of the liquid metal dissipative element is simulated by combining the volt-ampere characteristic curves of the liquid metal dissipative module. Finally, the topology of energy dissipation circuit branches combined by GaInSn liquid metal and ZnO resistors is proposed. At the same time, the HVDC breaker model combined by a hybrid DC circuit breaker and energy dissipation circuit branches is constructed. The energy dissipation ratio and distribution law of GaInSn liquid metal and ZnO resistors in the composite type of circuit breaker are verified. The composite dissipation improves the overall energy dissipation density of the circuit breaker compared to the conventional ZnO resistors energy dissipation.

Prediction of Electric Vehicle Energy Consumption in an Intelligent and Connected Environment

Accurate energy consumption prediction is essential for improving the driving experience. In the urban road scenario, we discussed the influencing factors of energy consumption and divided the modes from various perspectives. The differences in energy consumption characteristics and distribution laws for electric vehicles using the IDM and CACC car-following models under different traffic flows are compared. An energy consumption prediction framework based on the LightGBM model is proposed. According to the study, driving range, acceleration, accelerating time, decelerating time and cruising time all significantly impact the overall energy consumption of electric vehicles. There are apparent differences in energy consumption characteristics and distribution laws under different traffic flows: average energy consumption is lower under low flow and increased under high flow. The CACC-electric vehicles consume more energy in low flow than IDM-electric vehicles. Under high flow, the opposite is true. The results show that the proposed framework has a high accuracy: the MAPE based on IDM datasets is 3.45% and the RMSE is 0.039 kWh; the MAPE based on CACC datasets is 5.57% and the RMSE is 0.042 kWh. The MAPE and RMSE are reduced by 33.7% and 50.6% (maximum extent) compared to the best comparison algorithm.

Numerical analysis of the effect of energy distribution on weld width during oscillating laser welding of aluminum alloy

The weld morphology of aluminum alloy oscillating laser welding has an important influence on the quality of welded joints. To understand the formation process of the weld morphology, the three-dimensional numerical simulation model and energy distribution model for circular shaped oscillating laser welding of 6061 aluminum alloy are developed in this paper to analyze the characteristics of weld morphology and the effect of the energy distribution on the weld width. The cross section of the weld and the energy distribution on the processing surface are obtained under the conditions of different oscillation frequencies. It is found that the left width of the weld is larger than the right width of the weld and the energy density on the left side of the weld is more concentrated than that on the right side of the weld. With the oscillation frequency increases, the weld width and peak of energy density decrease. Furthermore, the formation mechanism of the difference in weld width is revealed based on the energy distribution law of the oscillating laser welding process, which is of great significance for improving the quality of aluminum alloy oscillating laser welding.

The influence of the number of free surfaces on the energy distribution and attenuation law of blasting vibration signals from peripheral holes: field experiment and simulation

Tunnels are commonly excavated using drilling and blasting methods, and the surrounding rock is greatly affected by the vibration of surrounding hole blasting. To study the influence of the number of free surfaces on the energy distribution and attenuation law of surrounding hole blasting vibration signals, on-site experiments and numerical simulation experiments were conducted. The research results indicate that the higher the number of free surfaces, the smaller the peak vibration velocity. The longitudinal Fourier main frequency decreases with the distance from the monitoring point. The more free surface, the greater the centroid frequency and zero crossing frequency. In addition, numerical simulation shows that the degree of rock fragmentation after blasting increases with the increase of the number of free surface of rock.

Study on destabilization failure characteristics and energy evolution law of drilling holes

AbstractBorehole destabilization damage is an important factors affecting gas extraction efficiency. To derive the fracture development law, strain, and energy evolution characteristics of different borehole diameters, uniaxial compression experiments were conducted on prefabricated rock specimens with different borehole diameters. The results showed that the elastic energy and dissipation energy of the specimens with different pore diameters changed with the compression process, and the energy distribution inside the specimens. The results show that as the pore size of the specimen increases, the strain area damaged by tensile fracture gradually decreases and the strain area damaged by shear fracture gradually increases, and the damage of the dominant specimen gradually evolves from tensile fracture as the dominant factor to tensile fracture and shear fracture together as the dominant factor and finally to shear fracture as the dominant factor. For the whole compression process of pore size rock specimens, the total energy curve shows a nonlinear growth trend, and the elastic energy curve shows a nonlinear growth trend before the specimen damage and a cliff‐type decrease after the specimen damage. From the perspective of energy distribution, the elastic energy storage limit of the specimen decreases with the increase of the specimen pore size, the energy distribution law inside the rock specimen with pores changes, and the total energy absorbed from the outside gradually changes to the dissipated energy, resulting in an increasing proportion of dissipated energy, indicating that the larger the pore size, the larger the plastic deformation, and the more obvious ductile damage characteristics of the specimen with pores will be shown. The research analyzes the causes of destabilization of rock samples with different hole diameters and provides some theoretical guidance for the study of gas extraction drilling stability.

Image Processing and Feature Extraction for Hull Structure GMAW Based on Weld Pool Visual Sensing

Image processing and feature information extraction based on the visual perception of the weld pool are considered essential components of intelligent welding quality monitoring of hull structure gas metal arc welding (GMAW). The unstable characteristics, such as large spatter, much smoke, and strong arc light during hull structure GMAW, lead to the blurring of image acquisition and the difficulty of contour extraction of the weld pool. The present study is aimed at addressing the practical issues from two perspectives, i.e., a spectrum‐visual‐sensing acquisition system and an image‐processing and feature extraction algorithm. First of all, by analyzing the light energy distribution law and acquiring the optical parameters relevant to the cut‐off composite dimming and near‐infrared narrowband filtering, spectral sensing is employed in establishing models of arc light radiation to detect the strength of continuously distinctive spectral lines. Besides, an appropriate high‐speed charge‐coupled device (CCD) camera is selected to build a visual acquisition system, which can reduce the external interference of the arc light on the image acquisition of the weld pool. Afterwards, the implementation of an image‐processing fusion model based on the spatial information fuzzy C‐means (FCM) clustering analysis and Sobel edge detection operator accompanies the investigation of the geometric aspects of the weld pool image. In terms of clear segmentation of the interest region, the edge detection and accurate extraction of the target contour are successfully obtained. In the subsequent section, the Hough transform analysis is adopted to establish the geometric feature extraction model of the weld pool, with corner detection, conversion, and camera calibration as the core technology. Additionally, the left and right views of the image contour are calibrated to achieve the lossless conversion of corner pixels and physical coordinates. Finally, three other distinct image‐processing methods are designed to compare the segmentation effect of the edge contour with the fusion model, and then, the extraction accuracy of the geometric features of the weld pool is verified. The interference of the arc light and smoke has been demonstrated to be substantially diminished, which is attributable to the visual‐sensing system during image acquisition of the weld pool. The results of edge fusion of the weld pool image show that based on the GMAW using the FCM‐Sobel fusion method, a superior extraction accuracy of geometric features characterized by smoothness, continuousness, no breakpoints, and less noise has fulfilled the engineering requirements.

Research on the HHT-Based Analysis Method of Tidal Power Generation Power Distribution Law

Tidal power generation technology has advanced quickly in recent years. In this study, the Hilbert-Huang transform (HHT) was used to examine the electrical energy distribution law of tidal power generation according to the time periods of days, months, and years based on observed data for tidal power generation. Our analysis summarized the tidal power generation law as follows: in the span of one day, the motor ran for 14 h before shutting off for 10 h. The frequency was 28 Hz, and the maximum voltage was 259 V. The tidal power generation swung twice a month, reaching its peak in the middle of the month and its trough at the beginning. The tidal power output fluctuated twice a year, reaching its peak in August, September, and October and its trough in February, March, and April. In the investigation of tidal power generation patterns, the HHT transformation’s precision and potency were confirmed.

Energy distribution law of coal–rock combined body under confining pressure effect

Energy distribution law of coal–rock combined body under confining pressure effect

Study on Energy Distribution Law and Numerical Simulation of Mining Roadway Surrounding Rock

In underground engineering, the deformation and failure process of the surrounding rock of the roadway is always accompanied by the occurrence of energy. The study of the energy distribution law of the surrounding rock of the roadway plays an important role in its stability. This paper first theoretically analyzes the stress and energy distribution law of the surrounding rock of the roadway, then with the help of numerical simulation method, combined with the existing physical and mechanical parameters, based on the existing support parameters of Dongrong No. 2 Mine, gradually compares and analyzes the distribution of vertical stress and energy under the three support methods of no support, original support, and combined support, and the results found that the vertical stress distribution law under the three support methods is basically the same. High-stress areas appear on the two ribs of the roadway, and low-stress areas appear on the roof and floor. The range of high-stress areas from no support to combined support continues to decrease and becomes more evenly distributed. The energy distribution pattern is basically the same. The overall energy of the coal seam is high. There are high-energy areas at 2 m left and right of the roadway, and the roof and floor energy of the roadway is the smallest. The low energy area extends 5 m up and down, respectively. The range of high-energy areas from no support to combined support is shrinking, and the energy distribution is more uniform.

Attenuation characteristics of impact-induced seismic wave in deep tunnels: An in situ investigation based on pendulum impact test

The radiated seismic energy is an important index for the intensity assessment of microseismic (MS) events and the early warning of dynamic disasters. However, the energy of MS signals is significantly attenuated due to the heterogeneity and viscous damping of rock media. Therefore, the study on attenuation characteristics of MS signals in underground engineering has practical significance for the accurately estimation of radiated seismic energy. Based on a pendulum impact test facility and MS monitoring system, an in situ investigation was carried out to explore attenuation characteristics at a deep tunnel. The results show that the seismic energy and peak particle velocity (PPV) attenuation are exponentially related to the propagation distance. The attenuation coefficient of energy is larger than that of PPV. With the increase in the input impact-energy, the seismic energy attenuation coefficient decreases as a power function. An empirical relationship between energy attenuation coefficient and wave impedance of rock mass was established in this scenario. Moreover, the time-frequency characteristics and energy distribution laws of impact-induced signals were investigated by the continuous wavelet transform (CWT) and wavelet packet analyses, respectively. The dominant frequency of signals decreases gradually as the propagation distance increases. Based on the energy attenuation characteristics, a new method was proposed to calculate the released source energy of MS events in the field. This study can provide an insight into energy attenuation characteristics of seismic waves and references for attenuation correction in seismic energy calculation.

Energy evolution and distribution law of rock under thermal mechanical coupling

The characteristics of the energy evolution and distribution of rock during deformation and failure were studied based on thermal mechanical coupling tests completed by Min Ming at his Master?s thesis in 2019. Dissipated energy is greater than elastic energy at the crack closure stage, while elastic energy is dominant at the linear elastic stage. At the post-peak failure stage, elastic energy is released rapidly before 800?C and released slowly at 1000?C. A comprehensive evaluation index to examine the influence of temperature on rock strength and deformation ability was proposed from the perspective of elastic energy accumulation ability. The negative effect of temperature on the strength of the rock sample is weaker than that on the elastic modulus before 400?C. The negative effect of temperature on the strength of the rock sample is stronger than that on the elastic modulus after 600?C.

Study on characteristic stress and energy damage evolution mechanism of cemented tailings backfill under uniaxial compression

This study attempted to explore, at curing age, the characteristics stress and energy evolution of the cemented tailings backfill (CTB) under uniaxial compression. Based on the energy consumption theory, the energy parameters at the characteristic stress varing with the curing age was analyzed. Furthermore, the evolution law of energy distribution and the energy damage mechanism of the CTB were revealed, and the failure criterion of the CTB was established based on the elastic energy consumption ratio. The results showed that the characteristic stress of the CTB follow an exponential function increasing law with the increase of curing age and the characteristic stress of the CTB with larger cement-to-tailings (c/t) ratio increases more rapidly when the curing age is 3d ~ 14d. The total energy, elastic strain energy and consumption energy at the peak stress point of the CTB all follow the exponential function increasing law with the increase of curing age, and the increase of cement-to-tailings (c/t) ratio and curing age can significantly improve the energy storage limit of the CTB. The deformation and failure of the CTB mainly go through five stages: initial crack compaction stage, linear elastic deformation stage, steady development stage of microcrack, accelerated crack expansion stage and post-peak failure stage. According to the damage value D of the CTB and the growth law of dissipated energy, elastic strain energy and axial strain, the loading damage of cemented CTB can be divided as follow: initial damage stage, damage stationary stage, damage stable stage, damage rapid stage and damage failure stage. The slow growth and abrupt change of the elastic energy consumption ratio K in the post-peak stage can be used as the criterion for strength instability of the CTB.

The Control of Intramolecular Through-Bond and Through-Space Coupling in Single-Molecule Junctions

The Control of Intramolecular Through-Bond and Through-Space Coupling in Single-Molecule Junctions

Energy Distribution Law of Dynamic Failure of Coal-Rock Combined Body

The rock burst must be generated by energy. In order to explore the distribution law of energy in coal-rock system, based on the structural characteristics of coal and rock and the mechanical characteristics analysis of coal-rock combined body model, the calculation formula of energy distribution was given before the damage of same diameter coal-rock combine body and nonsame-diameter coal-rock combined body; the uniaxial compression experiments were carried out on the combined body, and the energy distribution before the failure of the combined body was calculated by using the energy distribution calculation formula. The results show that the greater the difference in hardness between the components of the combined body, the stronger the outburst proneness; the energy mainly accumulates on the weak component before the combined body is destroyed, and the hard components act as a clamping device. When the soft layers and the hard rock layers are interbedded, the energy accumulation ability of the soft rock layer is stronger than that of the hard rock layer, and the weak rock layer is the main carrier of energy accumulation. According to this, from the perspective of energy accumulation layer, for the energy-bearing structure, direct release energy and indirect release energy two kinds of rock burst prevention and control concepts and corresponding antiburst measures were proposed. At the same time, engineering practice, microseismic monitoring, and on-site measurement were conducted in Junde Coal Mine. The results show that the blasting pressure relief for the weak coal seam and the hard roof destroys the energy-bearing structure formed by the fine sandstone-coal-fine sandstone and effectively releases the energy and has a remarkable antiscour effect.

Subharmonic resonance bifurcation and chaos of simple pendulum system with vertical excitation and horizontal constraint

In order to improve the working performance and optimize the working parameters of the typical engineering pendulum of a typical system that it is abstracted as a physical simple pendulum model with vertical excitation and horizontal constraint. The dynamical equation of the system with vertical excitation and horizontal constraint is established by using Lagrange equation. The multiple-scale method is used to analyze the subharmonic response characteristics of the system. The amplitude-frequency response equation and the phase-frequency response equation are obtained through calculation. The effects of the system parameters on the amplitude resonance bandwidth and variability are clarified. According to the singularity theory and the universal unfolding theory, the bifurcation topology structure of the subharmonic resonance of the system is obtained. The Melnikov function is applied to the study of the critical conditions for the chaotic motion of the system. The parameter equation of homoclinic orbit motion is obtained through calculation. The threshold conditions of chaos in the sense of Smale are analyzed by solving the Melnikov function of the homoclinic motion orbit. The dynamic characteristics of the system, including single-parameter bifurcation, maximum Lyapunov exponent, bi-parameter bifurcation, and manifold transition in the attraction basin, are analyzed numerically. The results show that the main path of the system entering into the chaos is an almost period doubling bifurcation. Complex dynamical behaviors such as periodic motion, period doubling bifurcation and chaos are found. The bi-parameter matching areas of the subharmonic resonance bifurcation and chaos of the system are clarified. The results reveal the global characteristics of the system with vertical excitation and horizontal constraint, such as subharmonic resonance bifurcation, periodic attractor multiplication, and the coexistence of periodic and chaotic attractors. The results further clarify the mechanism of the influence of system parameters change on the movement form transformation, energy distribution and evolution law of the system. The mechanism of the influence of relevant parameters on the performance of the engineering system with vertical excitation and horizontal constraint is also obtained. The results of this research provide theoretical bases for adjusting the parameters of working performances of this typical physical system in engineering domain and the vibration reduction and suppression of the system in actual working conditions.

A study on energy distribution law of frame structure across ground fissure

In order to study the frame structure energy dissipation mechanism on the ground, a 3x3 span 5-story frame structure was used as the research background, and a shaking table test with a scale ratio of 1:15 was designed. Based on the prototype structure, a finite element model based on ABAQUS is established. The correctness of the finite element model is verified by experimental comparison. On this basis, the plastic energy dissipation and damping energy consumption of the structural beam and the plastic energy dissipation law of the column are analyzed. The weak part of the structure of the trans-ground fissure structure under energy conversion is found. This study provides a reference for the arrangement of energy-consuming devices in seismic design and disaster prevention and mitigation design for similar structural engineering.

Aerial Target Tracking Based on Frequency-Domain Gabor Filters and Correlation Filters under Complex Interference Environment

Aerial infrared target automatic tracking technology is the core technology of the photoelectric countermeasure system of infrared imaging missiles. Aiming at challenging conditions of complex battlefield environment, large scale change of air target, infrared interference partial occlusion and so on, we propose a new correlation filtering algorithm based on Gabor filtering features in the frequency domain for aerial infrared target tracking. This algorithm constructs a set of frequency-domain Gabor filters, which extracts frequency-domain Gabor filtering(GF) features of the target image block and reduces dimension fusion, thereby effectively suppressing background noise and highlighting target texture information. According to the characteristics and variation law of spectrum energy distribution, the eigenvectors of target spectrum scale are extracted to improve the accuracy of target scale information estimation. High-confidence patches are used to track the reliable part of the target, and the energy distribution of the tracking box is calculated to predict the occluded part of the target simultaneously. This method provides more target information and improves the robustness of the algorithm in case of reappearance of the occluded target. Compared with other tracking algorithms, the average accuracy of the proposed algorithm was improved by 15.2%, and the frame frequency reached above 110 Hz.

Proper Orthogonal Decomposition Analysis and Dispersion Characteristics of Resonant Acoustic Flow

The investigation on the flow field and mixing characteristics of resonant sound mixing is of great significance for the dispersion mixing of superfine materials. In order to simulate the flow field and dispersion characteristics of resonant acoustic mixing, a gas-liquid-solid three-phase flow model based on the coupled level-set and volume-of-fluid (CLSVOF) and discrete particle model (DPM) was established. The CLSVOF model solves the gas-liquid interface, and the DPM model tracks the particle position. Then, the particle image velocimetry (PIV) experiment was performed using a self-made resonance acoustic hybrid prototype under different oscillation accelerations, and the radial velocity distribution between the experiment and simulation was compared. Finally, the proper orthogonal decomposition (POD) is used to decompose the flow field under different oscillation accelerations and fill levels, and the energy distribution law and the energy structure of different scales are extracted. The results show that the energy of the instantaneous flow field of the resonant sound is mainly concentrated in the low-order mode, and a close relationship was revealed between the energy distribution law and dispersion behavior of particles. The larger the small-scale coherent structures distribute, the more energy it has and the more favorable it is for fast and uniform dispersion.

Mechanical properties and energy development characteristics of impact-prone coal specimens under uniaxial cyclic loading

Energy is the intrinsic driving factor of rock dynamic failure. In this paper, the mechanical properties and energy development characteristics of impact-prone coal are studied. The stress and strain data and the acoustic emission (AE) signals of the impact-prone coal specimens are obtained by conducting cyclic loading-unloading tests. The elastic modulus deterioration rate is defined to describe the deterioration of the mechanical properties of the specimens during the loading process. The calculation results show that the elastic modulus deterioration rate of the impact-prone coal specimens during the cyclic loading process is as low as 3%. The AE monitoring results show that the AE signal is rare in the loading-unloading cycle before failure, and a large number of AE signals are generated at the failure moment. The stress-strain data are used to analyze the energy storage and distribution law of the loading process of impact-prone coal specimens. The results show that the input energy density increases nonlinearly with the increase of the load, and the input energy is mostly stored in the rock as elastic strain energy. The dissipative energy density is linear with the axial load. The impact-prone coal specimens have a strong ability to store elastic energy, and the precursor of damage and failure is not obvious. The study in this paper reveals the cause of the impact-prone coal easily induced to coal bursts from the energy point of view.

Effects of characteristics of bed structure on separation of 6-0 mm high-sulfur fine coal in a compound dry separator

ABSTRACT Large amounts of fine coal are produced during coal mining as a result of the extensive deployment of the mechanized mining technology and should be cleaned with the consideration of energy source conversation and environment protection, Urgent need for fine coal (especially high sulfur content fine coal) sorting desulfurization technology. On the basis of an analysis of raw coal, the use of a compound dry separator is proposed in this paper to separate high-sulfur coal across the full-size range of 6–0 mm. The relationship between the change of bed structure and the distribution of bed sulfur content and the force law of the particles is analyzed emphatically. The effect of the change of the backboard angle and the change of the clapboard length and height on the migration trajectories and vibration energy distribution of the material during the sorting process was studied systematically. The results showed that when the backboard angle was 45°, the clapboard length and height were 250 mm and 55–60 mm, respectively. The materials are sufficiently stratified, the sulfur content distribution regularity significantly. The law of vibration energy distribution is significant, and the maximum values of the particles force in the clean coal and gangue are 12.3 mN and 14.1 mN, the vibration acceleration of the clean section and the gangue section are 33.5m/s2, 20.6m/s2, the high sulfur content materials are mainly concentrated in the gangue section. The yields of the clean coal and gangue were 71.45% and 28.55%, respectively, with corresponding sulfur contents of 0.93% and 25.24%. The probable error (E) was 0.14g/cm3.