Journal of Mechatronics and Artificial Intelligence in Engineering
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Research on the heat transfer and internal residual stress of multi-phase systems
Get PDFThe incompatibility of inherent physical properties of the individual constituents often leads to the failures of the whole multi-phase system during the service. We need to investigate the residual stress caused by different inherent properties of the constituents that could finally cause the failure of the whole system and predict the severe time. This paper synthesized a special network-structure composite as the investigated system. The hybrid composites have a honey-comb structure with the high thermal conductivity HfB2 encapsuling the low thermal conductivity B4C. Although the overall thermal conductivity is greatly improved, the different thermal expansivity of the composites can result in a severe residual stress within the composite, which will finally evolve into macroscopy cracks and becomes a threat to the normal operation of the whole system. It is therefore necessary to investigate the magnitude of residual stress and its corresponding distribution. We employed the real-situation modeling and finite element analysis to probe the residual stress caused by the incompatibility of thermal expansivity. This method is effective and has its practical value when applying in relevant industries applications for the prediction and preventing the possible accidents
Analysis of mechanical properties of steel-concrete joint of large-span hybrid beam bridge
Get PDFThe mechanical properties of the steel-concrete joint determine the mechanical properties of the whole bridge. The mechanical properties of the steel-concrete joint of Jianhua railway rigid-frame bridge are analyzed by using nonlinear finite element method. The results show that the overall stiffness transition of the joint is smooth, the maximum stress of concrete section and steel box girder section are lower than the design value of the strength, which indicates that the structural stiffness and strength of the steel-concrete joint section meets the requirements. The error range of the finite element analysis results and the measured data is within 6 %, which shows that the finite element method can simulate the actual stress state of the bridge and it could save a lot of time and energy compared to the actual test
Forecasting rainfall and potential for repeated events to predict flood areas in Banten province, Indonesia
Get PDFIn a period of ten years, from 2011-2020 rainfall in Indonesia is relatively high, with annual rainfall between 460.5-4,627.4 mm. The high rainfall has implications for flooding in several provinces. During this period, almost every year several areas in Banten Province experienced floods. To predict areas of Banten Province that have the potential for flooding, forecasts of rainfall and the potential for repeated occurrences of high rainfall are carried out. In making the forecast, observations were made at the Serang Meteorological Station, the Budiarto Curug Meteorological Station, the South Tangerang Climatology Station, and the Tangerang Geophysics Station. Rainfall data from the four stations were analyzed by Fourier transform, Gumbel method and Mononobe method. Distribution analysis results obtained rainfall in Banten Province between 0.0-607.9 mm with the length of rainy days per month between 0-26 days. Then, the results of the Fourier transform analysis; Banten Province included a monsoon rain pattern with unimodial rainfall. Furthermore, the results of the analysis of the Gumbel method and the Mononobe method, Banten Province included the category of moderate rain and tended to be heavy, even extreme. Based on the results of the analysis using these two methods, in 2025 in Banten Province, it is predicted that 11 % heavy rain, 3 % very heavy rain and 1 % extreme rain are predicted. In that year, it is predicted that there will be 65 sub-districts in Banten Province that have the potential for flooding. The sub-districts that have the potential for flooding are mostly located in Serang Regency, Serang City, Tangerang City, and South Tangerang City. This potential flood is predicted to occur in: January, February, March, April, May, October and November
A comparative analysis of different approaches used for modelling and solving differential equations in Simulink/MATLAB
Get PDFIn the paper, two new methods are developed and examined to implement a transfer function based approach in solving differential equations with Non-Zero initial conditions. A significant amount of time and effort is needed for solving differential equations theoretically or manually. Also, the obtained mathematical solutions to equations that represent various dynamic systems provide no graphical picture of the result. Using Simulink/MATLAB for modeling differential equations make the task of analyzing the behavior of systems easy and quick for the user. Beside, symbolic solutions and visual plots/graphs of the simulated results can be easily obtained and analyzed. Simulink uses different approaches to model a dynamic system such as differential equations in time domain (integrators based) or transfer function based and state space based. The paper addresses and compares different approaches used in Simulink for implementing block diagram based mathematical models of differential equations with non-zero initial conditions. Customarily, a transfer function based approach is used for analyzing systems with zero initial conditions. The paper demonstrated how to use a transfer function based approach for solving differential equations with non-zero initial conditions and two ways are devised to successfully implement the approach. To conclude, dynamic behavior of circuit and systems is analyzed and examined by obtaining graphical solutions with different approaches for chosen system parameters
Nonlinear dynamic analysis of constant-speed and variable-speed of autonomous vehicle passing uneven road
Get PDFThis paper focuses on the research about the comfort and safety of autonomous vehicles passing consecutive speed control humps (SCHs) at a highway, compares and analyzes the nonlinear dynamic characteristics of vehicles driving on uneven roads at a constant speed or with accelerations or decelerations. Firstly, a speed coupling excitation model of the consecutive SCHs and a four-degree-of-freedom (4-DOF) nonlinear vehicle suspension model are established, and then the numerical simulation is carried out by using the four-order fixed-step Runge-Kutta algorithm. The nonlinear dynamic characteristics are analyzed by means of a bifurcation diagram, phase portrait, Poincaré map, time history and power spectrum. Through the analysis, the relevant nonlinear motion characteristics and the speed critical conditions of chaotic vibration of autonomous vehicle suspension under these three conditions are obtained. The results show that chaotic motion may occur when the vehicle passes the uneven road in all three cases, and motion is not periodic during acceleration. Therefore, the vehicle should not accelerate passing continuous SCHs. The experimental results provide support for the follow-up researches of autonomous vehicle, because they give information on how to avoid chaotic motion, speed adaptive control, driving comfort and driving safety
Effect of the geometrical parameters on the vehicle's moving stability
Get PDFTo enhance the moving stability and safety of vehicles, kinematics and dynamics model of the vehicle consisting of a guided front wheel and a free rear wheel is established based on the model of a four-wheeled vehicle when the vehicle moves on the curve-road. The effect of the geometrical parameters and dynamics parameters including the factor of the moving stability, vehicle moving speed, lateral stiffness parameters of the front and rear wheels, vehicle mass, vehicle length on the vehicle moving stability and safety is then simulated and analyzed, respectively. The research results indicate that the operating parameters of the vehicle greatly affect the vehicle moving stability. The lateral stiffness parameters of the front and rear wheels should be increased while the vehicle mass needs to be reduced in the operating condition of the vehicle to enhance the vehicle moving stability. Besides, the vehicle length L should be reduced and the longitudinal distance of a needs to be distributed by 0.95×a to further improve the vehicle moving stability
Modelling and experimental investigation of the vibratory conveyor operating conditions
Get PDFThe paper’s objective is to study the dynamic parameters and operating conditions of the vibratory conveyor, which is based on the double-mass oscillatory system and equipped with the pull-type (single-cycle) electromagnetic exciter. The scientific novelty consists in substantiating the conveying capacity of various standard sizes of bolts at different operating conditions defined by the input parameters, particularly supplied voltage. In order to describe the conveying tray vibrations, the simplified mathematical model of the conveyor’s double-mass oscillatory system is developed using the Euler-Lagrange equations and is numerically solved in the Mathematica software with the help of the Runge-Kutta methods. The experimental investigations are carried out at the Vibroengineering Laboratory of Lviv Polytechnic National University and are focused on testing the conveying speed of various bolts at different motion conditions: detachable (bouncing, hopping, jumping over the conveying surface) and non-detachable (sliding along the conveying surface). The obtained results show the basic kinematic parameters of the conveying tray motion at different voltages supplied to the actuating electromagnet and the dependencies of the conveying speeds of various bolts at different motion conditions mentioned above. The paper may be useful for designers and researchers while improving and implementing similar vibratory equipment in various industries
Studies on tensile and tear fracture of the S8210 tarpaulin
Get PDFThe tarpaulin of PVC-coated S8210 wagons is a composite textile membrane. This material is resistant to atmospheric factors (wind, rain, snow, etc.), durable for many practical applications and can be manufactured in various colors and prints. PVC membrane material is inexpensive, soft and easy to manufacture. These materials are widely used in large-opening spatial structures due to excellent mechanical behavior and beautiful textures. The tarpaulins are made by the method of welding with high frequency currents from the material S8210. In the present paper, the tensile and tearing mechanical properties of tarpaulins intended to protect goods carried by railway wagons are presented. The results of this study can be used in establishing the appropriate utilization of the fabric, in accordance to the warp and weft directions
Mathematical model and motion analysis of a wheeled vibro-impact locomotion system
Get PDFThe paper is aimed at investigating the motion conditions of the wheeled vibro-impact locomotion system equipped with the twin crank-slider excitation mechanism and the additional braking mechanisms allowing only one-way rotation of the wheels. The novelty of the present research consists in the improved mathematical model describing the motion conditions of the vibro-impact system and the proposed parameters optimization technique that allows for maximizing the average translational velocity of the wheeled platform. The main idea of this technique is to provide the maximal velocities of internal bodies when they get in contact with the corresponding impact plates. The numerical modeling results describing the dynamic behavior of the vibro-impact system are obtained in Mathematica software and substantiate the correctness of the developed mathematical model and of the proposed parameters optimization technique. The paper can be of significant practical and scientific interest for researchers and engineers studying and improving the vibratory locomotion systems, e.g., for inspecting and cleaning the pipelines
Optimal PMU placements using sea lion optimization for adaptable distribution system
Get PDFThe technological advancements and policy reformations make the electric power distribution system an active network. The modern power system operational regulations encourage coordinated network operations among various entities and customer participation. Unlike traditional operational environments, real-time monitoring has become a mandate for secure and reliable operations. Phasor Measurement Units (PMU) is the most reliable data acquisition tool, and their application for State Estimation (SE) has already been proven. This work extends the application of PMUs for the distribution system. A multi-objective optimization framework is proposed considering the optimal placement of PMU, network reconfiguration, and topology expansion. A novel optimization tool, the sea lion optimizer has been chosen to address the developed optimization problem. The proposed operational model is employed in IEEE RBTS-2 bus system, IEEE 33 node system and 69 node radial distribution network. Numerical results provide new insights into PMUs role in enhancing distribution network operations. The statistical indices confirm that the intended optimizer performs well in the chosen highly constrained optimization environment