Journal of Mechanical Engineering, Automation and Control Systems
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Finite element analysis of rockfall impact on pipelines with different erosion resistant coatings
Get PDFIn this paper, the finite element analysis method is used to extensively study the response of rockfall impact on pipelines with different erosion resistant coating. Based on the numerical results, the safety of the pipeline is comprehensively evaluated. Firstly, through the establishment of detailed pipeline and rockfall models, the impact of different rockfall materials and speeds on the pipeline is simulated. The results of the finite element analysis indicate that rockfall impact can cause significant stress concentration and deformation in the pipelines and damage to the coating. With the increment of impact speed, the damage to the pipeline also increases significantly, and different rockfall materials exhibit varying damage conditions, and it is found that fibreglass reinforced epoxy is better than the polyethylene coating. By comparing the analysis results under different conditions, the safety threshold of the pipeline under various rockfall impact scenarios is obtained. This provides an important theoretical basis and reference for the protection design and safety maintenance of the pipeline. The research in this paper not only aids in deepening the understanding of the mechanism of rockfall impact on pipelines but also serves as a valuable reference for improving the safety and reliability of pipeline engineering
Vector analysis of unmanned aircraft sea surface imaging characterization based on ISAR
Get PDFUtilization of airborne Inverse-Synthetic-Aperture-Radar (ISAR) for detection of moving targets on the sea surface is studied in this paper. In order to systematically analyze the characterization of radar imaging in the presence of both motion and observation uncertainty of a target, this study incorporates the Bayes-PRM multi-query algorithm for fusing ISAR multi-sensing information. The algorithm isochronously samples the physical quantities, such as UAV position, altitude, pitch angle, and velocity as a sequence of multivariate groups, and converts the time-series data of the trajectories into distributional features in graph theory. The coupled edge weights and Alternating Direction Method of Multipliers (ADMM) are introduced through the coupling framework combined with the ambient graph. With ADMM, the quadratic penalty term is used to achieve a simple linear function, and subproblems involving amplitude, linear velocity, and yaw angle can be embedded in a sequential solution scheme. The quality of the primal and dual solutions is then improved in an iterative manner to achieve vector analysis of the UAV. The potential maneuvering region of the target is fitted to a Gaussian-Wiener stochastic movement model, which in turn yields the detection expectation through point set coverage. By analyzing the tracking simulation results and diffraction theory, the experimental results are transformed into a function of the UAV multi-vector, and the angular linearization model of the multi-vector under the radar image is developed, which solves the optimal elevation angle and the optimal path for the maximum scanning radius of the airborne radar. The nominal trajectory of the UAV is effectively obtained, which confirms the improvement of the credibility of ISAR in target detecting. Through the proposed model, the results of object detection accuracy were improved
Constructing the schematic and mathematical model of the dynamics of a vibratory drum separator
Get PDFA structural diagram of a vibratory drum separator has been developed, and based on it, a mathematical model of the separator’s oscillatory motion has been constructed. The mathematical model was built using nonlinear mechanics methods and Lagrange equations. The obtained dependencies allow for determining the influence of geometric and physico-mechanical parameters on various factors affecting the intensity of the separation process. The research results should be used both at the design stages of vibratory separators and when selecting their parameters and operational modes
Influence of the welding cycle on the parameters of material damageability of the high-strength steel connection with an austenitic seam
Get PDFThe distribution of macrohardness of the material of a welded joint made of high-strength steel in the vicinity of a weld with an austenitic structure has been studied. The characteristics of the material's homogeneity, technological damageability, and the intensity of its growth have been determined using the LM-hardness method. The obtained characteristics of the material are considered according to the distance from the axis of the weld. It is shown that using the dispersion of important physical and mechanical characteristics to analyze the material homogeneity makes it possible to consider the differences in relation to the base material, structure, and properties of the weld. The method used in the work to assess the material damageability can be used for a welded joint that is heterogeneous in material. The obtained results are applicable in developing the technique of heterogeneous weld joints made of high-strength steels, as well as in the study of existing welded critical structures of long-term operation, in particular, main pipelines
Analysis and experimental research on the reliability of the connection between large-diameter bridge piles and caps
No full textThis article investigated the construction conditions of the pile foundation in the Wuxing section of the “Shanghai Suzhou Huzhou” railway bridge project. To test the reliability of large diameter connectors, it has established a finite element model with ABAQUS software for numerical simulation. Based on on-site tests, the reliability of the connection between the pipe pile and the cover steel was studied. According to the simulation results, when the load is P= 900 kN, the displacements of A2 and A3 steel pipe piles are 55.8 mm and 60.1 mm, respectively. The load-displacement relationship shows a high-order curve distribution. According to the results of on-site experiments, the displacements are 77.9 mm and 60.2 mm, respectively. The load-displacement relationship is linear. The results for the simulation and on-site testing are consistent. This study provides a basis to the research on the reliability of the connection between large-diameter steel pipe piles
Optimal path for automated pedestrian detection: image deblurring algorithm based on generative adversarial network
No full textThe pedestrian detection technology of automated driving is also facing some challenges. Aiming at the problem of specific target deblurring in the image, this research built a pedestrian detection deblurring model in view of Generative adversarial network and multi-scale convolution. First, it designs an image deblurring algorithm in view of Generative adversarial network. Then, on the basis of image deblurring, a pedestrian deblurring algorithm in view of multi-scale convolution is designed to focus on deblurring the pedestrians in the image. The outcomes showcase that the peak signal to noise ratio and structural similarity index of the image deblurring algorithm in view of the Generative adversarial network are the highest, which are 29.7 dB and 0.943 dB respectively, and the operation time is the shortest, which is 0.50 s. The pedestrian deblurring algorithm in view of multi-scale convolution has the highest peak signal-to-noise ratio (PSNR) and structural similarity indicators in the HIDE test set and GoPro dataset, with 29.4 dB and 0.925 dB, 40.45 dB and 0.992 dB, respectively. The resulting restored image is the clearest and possesses the best visual effect. The enlarged part of the face can reveal more detailed information, and it is the closest to a real clear image. The deblurring effect is not limited to the size of the pedestrians in the image. In summary, the model constructed in this study has good application effects in image deblurring and pedestrian detection, and has a certain promoting effect on the development of autonomous driving technology
Improving piano music signal recognition through enhanced frequency domain analysis
Get PDFFeature extraction is a crucial component in the analysis of piano music signals. This article introduced three methods for feature extraction based on frequency domain analysis, namely short-time Fourier transform (STFT), linear predictive cepstral coefficient (LPCC), and Mel-frequency cepstral coefficient (MFCC). An improvement was then made to the MFCC. The inverse MFCC (IMFCC) was combined with mid-frequency MFCC (MidMFCC). The Fisher criterion was used to select the 12-order parameters with the maximum Fisher ratio, which were combined into the F-MFCC feature for recognizing 88 single piano notes through a support vector machine. The results indicated that when compared with the STFT and LPCC, the MFCC exhibited superior performance in recognizing piano music signals, with an accuracy rate of 78.03 % and an F1 value of 85.92 %. Nevertheless, the proposed F-MFCC achieved a remarkable accuracy rate of 90.91 %, representing a substantial improvement by 12.88 % over the MFCC alone. These findings provide evidence for the effectiveness of the designed F-MFCC feature for piano music signal recognition as well as its potential application in practical music signal analysis
Design and analysis of tracking differentiator based on SO(3)
Get PDFMotivated by the issue of insufficient dynamic performance and tracking accuracy in SO(3)-based attitude tracking differentiators during large-angle maneuvers and complex trajectory tracking, a novel design approach for a three-degree-of-freedom attitude tracking differentiator within the SO(3) framework is proposed by incorporating second-order system theory and Lie group theory and improving the classical tracking differentiator. The kinematics model and error dynamics model of a rigid body on SO(3) are derived, and a reasonable virtual control input on SO(3) is constructed subsequently in order to achieve better dynamic response and tracking performance. Simulation and experimental results validate that the designed tracking differentiator could realize rapid and smooth convergence during large-angle maneuvers, and the initial large tracking error rapidly drops to near zero in a short period of time; additionally, it can also track expected time-varying curves well in complex trajectory tracking, with initial errors rapidly decreasing and maintaining at normal levels, demonstrating excellent tracking and control capabilities. There are strong application prospects for this new approach in addition to its theoretical significance
Interconnections between local Schumann resonances and episodes of kidney disease
Get PDFThe aim of the study was to evaluate the interconnections between local Schumann resonances of the Earth’s magnetic field and episodes of kidney disease. Materials and Methods: Study participants included 716 males and 624 females who had episodes of kidney disease during the period of 1 January 2021 to 31 December 2021 and attended the Department of Nephrology at the Hospital of Lithuanian University of Health Sciences, Kauno klinikos. Time varying magnetic field data was collected at the magnetometer site located in Lithuania. Results and Conclusions: The study results support the hypothesis that the Earth’s magnetic field has a relationship between the number of nephrology patient hospitalizations per week and the average weekly local Schumann resonances strength in different frequency ranges. Working hypotheses are proposed for the mechanisms of the influence of the Earth’s electromagnetic field on kidney function: а) quantum mechanical features of the atomic composition of renal tissue molecules determine a kidney-specific reaction; b) cyclotron resonance mechanism; c) resonant response of cells of morphological structures of kidney tissue to external bioactive frequencies in the range of 6-8 Hz; d) mechanism of indirect influence of blood as a magnetically saturated medium
Solving Saint Venant torsion problems for rectangular beams using single finite Fourier sine transform method
Get PDFThis research presents the single Fourier sine transform method (SFSTM) for solving the Saint Venant torsion problem of rectangular prismatic bars. The problem is a common theme in the theory of elasticity of unrestrained torsion which was previously expressed by Prandtl using Prandtl stress functions ϕ(x,y) as a Poisson type nonhomogeneous partial differential equation (PDE) called the stress compatibility equation. In this work the SFSTM was applied to the stress compatibility equation, converting the PDE to an easier to solve ordinary differential equation (ODE) in the transformed domain. The boundary conditions were used to find the integration constant and inversion was used to find the solution in the physical domain. The non vanishing stresses and torsional moments were thus found as a single series of infinite terms with rapid convergence. The maximum stresses and moments were found in standard form in terms of torsional parameters which were tabulated for various ratios of the cross-sectional dimensions. A comparison of the torsional parameters with previous results show that the present results are identical with previous results illustrating the accuracy of the SFSTM used. The sine kernel of the SFSTM satisfies the boundary conditions of the problem and contributed to the exact solution obtained. The SFSTM simplified the PDE to an ODE which is simpler to solve