Movable Load Research Articles

Vehicle flow indication and identification using FBG sensors

Abstract This paper proposes a vehicle flow monitoring system utilizing fiber Bragg grating (FBG) sensor technology. The system comprises a prototype road model along with a car with varying loads. The FBG sensor is embedded in the road surface for sensing the strain induced by the vehicle movement. The laboratory experiments were conducted using an embankment model equipped with FBG sensor to identify vehicle movement under static and movable loads. Under static condition, different loads were applied on the car and the corresponding wavelength shifts have been measured using FBG-interrogator. Under dynamic condition, the vehicle was moved with certain speed and the corresponding wavelength shifts were recorded over time. The sensitivity of FBG for vehicle load sensing has been obtained as 0.3 pm/N. The proposed vehicle flow sensor system offers good accuracy and sensitivity and has potential applications for real-time vehicle flow monitoring. The proposed sensor system can be used to analyze road surface irregularities, crucial for assessing heavy-vehicle fatigue.

Multifunctional Bandpass Filter/Displacement Sensor Component

This paper presents the design and realization of a multifunctional bandpass-filter/displacement-sensor using an edge-coupled microstrip bandpass filter loaded by a pair of split ring resonators (SRRs). It is shown that while the structure acts as a bandpass filter at its operating frequency, the phase of the reflection coefficient from a movable loading resonator at the resonance frequency of the resonator can be used for displacement sensing. With this aim, and to avoid any interference with the filter functionality, the resonance frequency of the SRRs is chosen within the stopband of the bandpass filter, where all the input signal is reflected back to the input port. Therefore, moving the loading resonators does not have any adverse effect on the filtering performance. To validate the concept, a fifth-order Chebyshev bandpass filter with a feed line loaded with a pair of SRRs is designed and the numerical evaluation of the proposed multifunctional bandpass-filter/displacement-sensor is provided. The proposed multifunctional component is also validated through fabrication and measurement. It is shown that the proposed component has a sensitivity of 8°/mm at the designed frequency of SRRs. However, the sensitivity can be increased by scaling the SRRs to resonate at a higher frequency within the upper stopband of the filter.

Optimal Scheduling of Movable Electric Vehicle Loads Using Generation of Charging Event Matrices, Queuing Management, and Genetic Algorithm

The extensive adoption of electric vehicles (EVs) can introduce negative impacts on electric infrastructure in the form of sporadic and excessive charging demands, line overload, and voltage quality. Because EV loads can be movable around the system and time-dependent due to human daily activities, it is therefore proposed in this research to investigate the spatial effects of EV loads and their impacts on a power system. We developed a behavior-based charging profile simulation for daily load profiles of uncontrolled and controlled charging simulations. To mitigate the impact of increased peak demand, we proposed an optimal scheduling method by genetic algorithm (GA) using charging event matrices and EV queuing management. The charging event matrices are generated by capturing charging events and serve as an input of the GA-based scheduling, which optimally defines available charging slots while maximizing the system load factor while maintaining user satisfaction, depending on the weight coefficients prioritized by the system operator. The EV queuing management strategically selects EVs to be filled in the available slots based on two qualification indicators: previous charging duration and remaining state of charge (SoC). The proposed methodology was tested on a modified IEEE-14 bus system with 3 generators and 20 transmission lines. The simulation results show that the developed methodology can efficiently manage the peak demand while respecting the system’s operational constraints and the user satisfaction level.

Bi-level framework for microgrid capacity planning under dynamic wireless charging of electric vehicles

The battery energy storage system in the microgrid can regulate energy and maintain the stability and continuity of renewable energy generation. This paper presents a new microgrid structure with in-motion electric vehicles as a distributed energy storage system. This structure combines the technology of dynamic wireless charging, allowing in-motion electric vehicles to participate in the energy regulation of the microgrid. The proposed microgrid mainly consists of wind turbines, photovoltaic arrays, as well as dynamic wireless charging facility. Two different planning objectives, i.e., maximizing the microgrid utility and minimizing the total generalized social cost, are investigated respectively. Taking into account the response of EV users to the microgrid capacity plans, we propose a bi-level framework. Further, an algorithm based on the surrogate model is used to solve the bi-level programming, where the radial basis function interpolation model is utilized to approximate the objective function. Finally, in case studies, the influence of parameter variations on the results is explored. The feasibility and advantages of the proposed microgrid capacity planning are demonstrated. Further, through the studies of the uncertainties of wind speed, light intensity, base load, and movable load, it is illustrated that the objective value can maintain good stability under the optimal capacity plan.

Optimal torque distribution of distributed driving AGV under the condition of centroid change

The torque distribution is researched under the condition of the centroid position of distributed drive automatic guided vehicle (AGV) with load platform and is uncertain due to the unknown movable load. The whole vehicle model under centroid variation, the efficiency model of the hub motor and the torque distribution control strategy based on a PID neural network are established. A hierarchical controller is designed to accurately ensure the economy and stability of the vehicle. Simulations of the proposed control strategy are conducted, the results show that the total power and lateral deviation distance of the driving wheels are reduced by 17.63% and 61.54% under low load conditions and 15.54% and 61.39% under high load conditions, respectively, compared with those of the driving wheels under the average torque distribution, and the goal of close slip rates of the driving wheels is achieved. A system prototype is developed and tested, and the experimental results agree with the simulation within error permissibility. The margin of error is less than 5.8%, the results demonstrate that the proposed control strategy is effective. This research can provide a theoretical and experimental basis for the torque optimization distribution of distributed drive AGVs under centroid variation conditions.

Stress-Strain State of a Composite Plate Under the Action of a Transient Movable Load

Stress-Strain State of a Composite Plate Under the Action of a Transient Movable Load

Some features of oscillations and stability of reinforced cylindrical shells under action of movable inertial loading

This paper describes some features of the mathematical models for the elastic shell with movable load and for the elastic elements of changeable length. In these systems two forms of eigenoscillations - the eigen component and the accompanying one, displaced in phase to the right angle correspond to every frequency of the system. The accompanying component is caused by the mobile inertia load or by the changeable length and they are non-trivial when those factors are present. As well as for objects with time-varying length, these problems lie in outside of the scope of the classical problems of mathematical physics due to that the eigenfrequencies and eigenforms will be presented as time-nondependent functions. This non-classical section of the mathematical physics is waiting for its development, new researches and generalizations. The main attention of this work is paid to the elastic systems with the mobile inertia load. The problem of oscillations and stability of thin cylindrical envelope with regular stringer set is being considered under assumption that they are regularly placed with a small step from one to another. Also, we assume that there is unsymmetrical stream of mobile inertia load. There is a wide variety of problems in area of jet engine, cooling systems, flying, and floating vehicle framework’s design, which boil down to such computational schemes. The linear theory of structural-orthotropical envelopes with equilibrium equations and geometrical Donnel-Mushtary relations are being used to obtain of the discussed problem formulation. We assume that ribs of the shell are considered as Kirchhoff-Klebsh bars. The accurate solution of the problem is obtained by using of two-waves representation for motion and it has been applied for research on influence of geometry, elastic and structural parameters on the oscillation and stability properties of the shell.

Reconstruction of the suspended pedestrian bridge through the River Bug to border island

The results of the technical examination of the pedestrian bridge over the Western Bug River on the territory of the Brest Fortress are presented. A new constructive solution of the bridge, the results of its numerical modeling and the features of installation are presented. The fullscale tests of the bridge with a movable test load confirmed the design decisions made by the authors. The resulting efforts in the ropes did not exceed the calculated values.

To the problem of train running safety

The paper is presenting the procedure used for establishing the cause of the wagon derailment. To do this, the computer simulations and the computational software, developed in the Dnipro National University of Railway Transport (DIIT) were used. The level of longitudinal forces and the wagons dynamic performance have been evaluated using the mathematical models of longitudinal oscillations of a train and the spatial vibrations of wagons, in particular of tank wagons. As a result of modeling we obtained oscillograms of longitudinal forces in each inter-wagon connection, the dependence of the largest longitudinal forces on travel time and distance traveled, the distribution of the maximum longitudinal forces along the train length, the speed dependence on travel time and track coordinates. We also obtained the dynamic performance of wagons: the vertical dynamics coefficients of the axle-box and central suspension, the horizontal dynamics coefficients and the derailment stability coefficient. The influence of the movable load in the tank wagons and the characteristics of rail irregularities on the stability coefficient against wheel climbing onto the rail is also considered. The presented methodology was used to determine the cause of the tank wagon derailment in a non-homogenous freight train consisting of 50 wagon tanks on an existing track section of the Lithuanian railways. When simulating the train movement, it was assumed that the train was equipped with elastic-friction absorbing devices and air distributors, turned on to the average operation mode. As a result of numerical experiments, an assumption was made about the cause of the train derailment.

Modeling of Constructions’ Structurally Nonlinear Oscillations Using Chebyshev's Polynomials

A numerical algorithm for solving initial-boundary value problems with nonlinear boundary conditions was developed and implemented. The algorithm is constructed with reference to modeling of oscillations of an elastically supported deformable rod with limit stops at the ends under the action of a moving variable force. Such a rod is the design scheme of a number of building structures, including the span structure of a floating bridge of continuous system with limiting rigid supports at the ends. Chebyshev's polynomials were used to improve the computational schemes for realizing the practical problems of modeling constructive-nonlinear oscillations of building structures. The solution does not lose stability for large values of the elasticity coefficients of elastic couplings. Using the developed approach, it is possible to perform virtual computing experiments to skip a variety of movable loads on the floating bridge to analyze its deformed state and to make well-grounded design decisions.

TORSIONAL STIFFNESS AS AN INFLUENCE PARAMETER ON ARCH STABILITY

Arch bridge springs can be connected to concrete abutments either by prestressing bars or by connectors. In both options, the torsional stiffness is substantially reduced, compared to the full arch cross sectional area. The influence of this lack of torsional stiffness on arch buckling is being researched, both numerically and experimentally. To reduce any residual stress during tests, wooden rods that simulate the arch were submerged in water and subsequently bent to the desired shape. Imperfections of the arch samples are measured. Two unequal concentrated loads are applied to the samples, thus simulating the effect of movable loads across half of the arch span. During loading, lateral deflections were measured until elastic buckling occurred. The simulation of more flexible rotation of the springs required replacing the cross section by thin equivalent side plates. Since all parameters have not been isolated, the results are limited yet. However, comparing the failure load of similar conditions, the reduction of torsion stiffness by 81.48% reduces the failure load by 26.3%. This indicates that total prevention of axial rotation may not be imperative for arch bridges.

Frequency and impedance reconfigurable antenna using magnetically-actuated low-loss Ferrofluid loads

ABSTRACTWith space and spectrum at a premium, antennas must be capable of operating well across a variety of frequencies and environments. This work presents a novel method of frequency and impedance reconfiguration through the actuation of a ferrofluid load with a permanent magnetic bias field, while still achieving up to 85% efficiency. Under a sufficiently strong bias field, the ferrofluid load behaves as a low-loss movable dielectric load, and the actuation method avoids the complexity associated with microfluidic pumps and DC bias networks. This work opens a new field of reconfiguration mechanisms for antennas through magnetic repositioning of low-loss ferrofluid loads.

Dynamics of Elastic Objects under Movable Inertial Loading - Some Features of the Mathematical Models and Analogies

This paper describes some features and analogies of the mathematical models for the elastic elements with movable load and for the elastic elements of changeable length. In these systems two forms of own oscillations - the own component and the accompanying one, displaced in phase to the right angle correspond to every frequency of the system. The accompanying component is caused by the mobile inertia load or by the changeable length and they are not trivial only when this factor exists. As for objects with time-varying length, these problems lie in outside of the scope classical problems of mathematical physics due to that the eigenfrequencies and eigenforms become time-dependent functions. This non-classical section of the mathematical physics is waiting for its development, new researches and generalizations.

Survey and Experimental Investigation of Movable Fire Loads in Japanese-Style Wooden Historical Buildings

ABSTRACTThis study investigated the movable fire loads and the characteristics of combustible materials in Japanese-style wooden historical buildings via field surveys and cone calorimeter experiments. Twenty-one historical buildings with 102 rooms and a total floor area of 2235.06 m2 were surveyed to determine the movable fire load. Strong correlations among fire load density, compartment floor area, and spatial use are found in this survey. The mean values of the movable fire load density in decreasing order in terms of room use are storeroom (431.38 MJ/m2), study room (298 MJ/m2), bedroom (294.88 MJ/m2), reception room (287.20 MJ/m2), and dining room (217.11 MJ/m2), providing fire engineering design with a reliable fire load setting in various types of rooms in historical buildings.

Charging Demand Forecasting Model for Electric Vehicles Based on Online Ride-Hailing Trip Data

Electric vehicle (EV) has been popularized and promoted on a large scale because of its clean and efficient features. Charging this increasing number of EVs is expected to have an impact on the electricity grid and traffic network. Therefore, it is necessary to model and forecast the EV charging demand. Most of the existing researches have not utilized real-world traffic data to analyze the EV charging demand. Few researches have considered and analyzed the characteristics of space-time transfer of charging load in urban functional areas. As an emerging mode of transportation, however, online ride-hailing trip data provide an ideal source for analyzing traffic planning and operation. On the basis of this, a charging demand forecasting model of EVs based on a data-driven approach was presented in this paper. In this methodology, it is firstly assumed that residents’ transportation trip demand is not restricted by vehicle categories(electric or fuel vehicles). The original trip trajectory data of Didi online ride-hailing were conducted to model via data mining and fusion. And the process of data analysis included region-scope selection, spatial grid modeling, trajectory data mapping, retrieval data identification and urban functional area clustering as well as traffic network modeling. Through modeling and processing, the following regenerative feature data were obtained: functional regional division (i.e., residential areas, industrial areas, commercial areas, and public service areas), trip rule distribution (i.e., temporal distribution and spatial distribution on weekdays, weekends and holidays) and actual driving path (i.e., driving path with the shortest distance or with the minimum time-consuming). And then, considering the movable load feature of EVs, vehicles were subdivided into three kinds such as private vehicles, taxis and other public vehicles, and the single EV model with driving and charging characteristic parameters was established. Furthermore, the regeneration data obtained from modeling and analysis along with the determined single EV model were supported as data sources and model for the charging demand forecast architecture. At last, the actual urban traffic network in Nanjing, China was selected as an example to design the path planning experiments and charging demand load experiments in different scenarios. The results demonstrate that this proposed model is able to realistically simulate the actual dynamic driving process of EVs, and effectively predict the spatial-temporal distribution characteristics and load transfer trends of charging demands in different date type as well as different functional areas. The model also lays a theoretical foundation for the subsequent research on investment and construction of charging facilities, as well as charging control and charging guidance of EVs.

A FBG based displacement transducer for small soil deformation measurement

A small soil deformation measurement system based on fiber Bragg grating (FBG) has been developed for underground displacement monitoring. This new displacement transducer consists of two anchorage plates for the fixation of displacement sensor in soil, a single FBG sensor for sensing the occurred deformation, and a PolyVinyl Chloride (PVC) tube for the protection of inner FBG sensor. The two anchorage plates were fabricated and fixed on the PVC tube surface by FDM process. Gauge length, maximum measurement displacement, and displacement resolution of the proposed FBG displacement transducer were 90 mm, 0.9 mm, and 0.0747 mm, respectively. Raw material of the anchorage plates was Polylactic Acid (PLA) material. An embankment model was established and installed with multiplexed four FBG displacement transducers for the measurement of internal horizontal displacement in laboratory. Both static load and movable load were applied on the top surface of the embankment model. It is found that maximum error of the four sensors under different static load was less than 6%. The monitored strains of four different FBG displacement transducers under movable load were highly consistent, indicating that the smart FBG based small deformation monitoring system can be used to monitor vehicle flow in future. All monitored displacement values were less than 0.03 mm. Therefore the FBG displacement transducer characterized by high resolution can be used to monitor small displacement occurred underground.

The residual lifetime of steel bridges under the action of fatigue and corrosion effects.

Decades-old steel bridges have to face the unfavourable environment that causes the ageing and deterioration of material properties. Moreover, especially railway bridges, which are famous for permanent resistance to heavy movable load, are exposed to large number of stress ranges that may lead to fatigue damage. Combination of both phenomenon has significant impact on the condition of bridges and their remaining service life. The subject of the proposed paper is observation the response of steel bridge structures containing construction elements weakened by corrosion on cyclic load. For the purpose, the series of laboratory fatigue tests were performed on samples of riveted connections. Specimens with various level of corrosion weakening had been taken from historical railway bridge and were loaded by cycling force in tension subsequently. The laboratory tests were supported by numerical analysis. This paper presents knowledges gained from the study that was focused on how to take into account the combined effect of degradation process and fatigue. The evaluation of the tests indicates that the service life of members may be significantly reduced due to fatigue. The developed relationship between corrosion loss and reduced detail category is stated.

Finite element modeling of a moving load using contact conditions

The article deals with the issues of simulation of the dynamic moving load on a span structure in the modern finite element systems. The possibility of using the contact conditions in the Midas NFX program to describe the coupled vibrations of a beam and a movable load is investigated. To verify the results obtained, the method of separate modeling of the moving load by use of several forces on the trafficway line is used. The series of numerical studies of an elastically supported dynamical system was performed using two techniques. Graphic charts are obtained mapping vertical displacements of the vibration system characteristic points, depending on the inertial properties of the moving load, on the nodal forces application step, the parameters of surface conditions.

Impact of the Movable Random Load on the Infinitely Long Beam Superposed on the Solid Viscoelastic Foundation

The problem of the movement of the load at a constant rate on an infinitely long beam superposed on the solid viscoelastic foundation has been considered. The load is considered to be an arbitrary function of the longitudinal coordinate. The impact of the load characteristics and the foundation on the critical speed value and the mean-square scatter of the beam deflection has been analyzed.

Optimal distribution reconfiguration considering high penetration of electric vehicles

The appearance of Plug-in Electric Vehicles (PEVs) in the electric grids is providing new opportunities when some new challenges are also created. Technically, PEVs are movable loads that can benefit to both owners and utilities in case of using Vehicle-to-Grid (V2G) technology. Therefore, this art icle aims to investigate the Distribution Feeder Reconfiguration (DFR) effect to optimally manage PEV performance in a probabilistic framework. The proposed stochastic framework will capture the uncertainties of location of PEVs as well as driving pattern and battery State-of-Charge (SOC). In addition, a new self-adaptive evolutionary swarm algorithm based on Social Spider Optimization (SSO) algorithm is proposed that will search the problem space globally. The simulation results on the IEEE standard test system shows the high performance of the proposed method.