Axle Type Research Articles

Deep Learning–Based Detection of Vehicle Axle Type with Images Collected via UAV

Deep Learning–Based Detection of Vehicle Axle Type with Images Collected via UAV

Traffic input module for mechanistic-empirical pavement design with weigh-in-motion data

• Weigh-in-motion data provides large quantity of traffic information for pavement design. • Reliability of pavement design highly depends on the quality of truck traffic data. • The weigh-in-motion recorded traffic data may not be sufficiently accurate for satisfactory pavement design. • The accuracy of weigh-in-motion traffic data can be improved through machine learning algorithms. The success of the mechanistic-empirical pavement design guide implementation depends largely on a high level of accuracy associated with the information supplied as design inputs. Truck axle load spectra play a critical role in all aspects of the pavement structure design. Inaccurate traffic information will yield an incorrect estimate of pavement thickness, which can either make the pavement fail prematurely in the case of under-designed thickness or increase construction cost in the case of over-designed thickness. The primary objective of this study was to create an accurate traffic design input module, and thus to improve the quality of pavement designs. The traffic input module was created with the most recent data to better reflect the axle load spectra for pavement design. The unclassified vehicles by weigh-in-motion devices were analyzed and a neural-network-model-based classification method was utilized to determine the appropriate allocations of unclassified vehicles to truck classes. The updated truck traffic information includes average annual daily truck traffic, truck volume monthly adjustment factors, truck volume lane distribution factors, truck volume directional distribution factors, truck volume class distributions, traffic volume hourly distribution factors, distributions of for single-axle, tandem-axle, tridem-axle, and quad-axle loads, average axle weight, average axle spacing, and average number of axle types.

Dynamic Behavior and Parameter Characteristics of Buried Pipeline in Airports

Buried pipeline, as one of the crucial facilities of airport ground engineering, has been extensively utilized for the transportation of petroleum, natural gas, industrial wastewater, and more. However, there are significant gaps in the research on the dynamic response of buried pipelines in airports under the action of dynamic traffic loads, which severely hampers the design and engineering quality of oil transmission pipelines. This study builds a three-dimensional finite element model to simulate the action of vehicles on the pipe–soil structure with actual loads. Moreover, the current research establishes a dynamic analysis model of pipe–soil interaction to analyze the material damping and load parameters. Using the structural dynamic response equation and Rayleigh damping calculation theory, this study investigates the change law of pipe dynamic stress and influencing factors and presents the recommended values of the parameters related to the pipe–soil interaction. Results are as follows. A damping ratio of 0.05 can enhance the time lag of the dynamic response of the structure and weaken the response peak. For the Rayleigh damping parameters, the viscous damping coefficient [Formula: see text] has almost no effect on the dynamic response of the pipe–soil structure, so it can be disregarded in the calculation. With the increase of the axial weight of the traffic load above the pavement structure, the peak value of each dynamic response quantity of the pipe–soil structure and load magnitude. The suggested value of the dynamic load coefficient of the pipe–soil structure is 1.5. Lastly, the earth pressure and dynamic load coefficients are suggested to take values for different load and axle type cases.

Novel cross wedge rolling method for producing railcar axles

Railcar axles are large-size parts manufactured in large batches using forging methods. More efficient methods of manufacturing railcar axles are currently being sought. A promising line of research in this respect is connected with the use of cross wedge rolling (CWR). Nonetheless, there exist no rolling mills that would make it possible to manufacture such large-size parts as railcar axles. A solution to this problem was inspired by the symmetric shape of a railcar axle, which makes it possible to roll this part in two passes using the same tools. Taking advantage of the potential offered by numerical modelling, simulations were made of two rolling processes for producing a railcar axle type BA302, i.e. one process was conducted with the use of two rolls and the other with two flat tools moving in the opposite directions. Numerical results demonstrated that railcar axles produced by the proposed rolling process had neither external nor internal (cracks) defects. The effectiveness of the developed CWR method was ultimately confirmed by the high quality of railcar axles that were produced (in a scale of 1:5) under industrial conditions at the Lublin University of Technology.

SIMPLIFIED MECHANISTIC – EMPIRICAL ANALYSIS OF FLEXIBLE PAVEMENT

Pavement stress-strain analysis is an ideal tool for analytical modelling of pavement behaviour and thus, constitutes an integral part of pavement design and performance evaluation. It is the fundamental basis for the mechanistic design theory. Predicting pavement response by simplified procedure analysis by relying on equivalency factors using axle load spectrum which is obtained from Weigh-In-Motion (WIM) data is aimed for this study. The framework for computing the structural response of the standard axle group loads on a pavement structure by using a layered elastic computer program and calculation of pavement responses for axle load distribution for different axle groups and axle types by using the theoretical analysis. From the study, the summary of the obtained results are as follows: (1) axle load distribution was developed for the four considered axle configurations; (2) Single axle with single tyre has the greatest destructive impact followed by the tridem axle with dual tyres (TRDT) and next by TADT. The least destructive axle group type is the Single Axle with Dual tyre SADT.The predicted pavement response by theoretical analysis indicates that the critical tensile strains obtained results are all greater than the critical vertical strains. At the heaviest axle load, from 70KN, for both SAST and SADT; from 140KN for TADT; and from 210KN, the critical strains have the greatest magnitude by SAST and followed by SADT and next by TADT. The least critical tensile strain is from the TRDT.

Deformation behavior of flexible pavements by finite element simulation

Flexible pavement is usually designed based on certain axle load limits and climatic conditions. The Iraqi code has specified certain load limits per each axle type that should not be exceeded. However, many trucks violate these limits by carrying additional weights to decrease the transportation cost. These overweight trucks cause severe deterioration to the pavement and thus reduce its life. The Iraqi authorities generally charges the violating trucks a penalty based on their weights. This penalty could be very small compared to the damage occurring to the pavement based on these over weights. Also, some trucks may carry huge weights that the pavement may not support, so unloading such trucks could be a suitable solution rather than paying few amounts of money and deteriorating the pavement. The study aims at studying the effect of axle load increase, and the variation in pavement moduli, on the overall pavement life. It also aims to estimate the overweight truck limits that could be penalized or unloaded. The research uses the ABAQUS software conditions to estimate the tensile strains occurring under the asphalt concrete (AC) layer and the compressive strains above the subgrade surface. These computed strains are incorporated in the fatigue cracking and rutting models to estimate the pavement life for different axle weights. Results showed that violating trucks should be unloaded when their weights exceed certain limits.

Research on the Recognition Method of the Axle End Mark of a Train Wheelset Based on Machine Vision

Whether the wheelset of a high-speed train has defects such as cracks is very important to the safety of high-speed trains. Hence, the wheelset must be regularly inspected for flaws. For flaw detection of a wheelset, it is necessary to record the axle end information of the wheelset to correlate with the flaw detection results. To quickly and accurately identify the axle end mark of the wheelset, an automatic identification method based on machine vision is proposed. Our method identifies seven types of marks on the axle end, including the smelting number, steel grade number, unit number, sequence number, year and month, axle type mark, and the azimuth mark. Using the established automatic identification method of axle end marks, based on Retinex theory, an improved dual-core Laplacian combined with Gaussian filtering operation is proposed to solve the problem of the low contrast of the wheelset axle end image. An improved image tilt correction algorithm based on the combination of Hough circle detection and bilinear interpolation is proposed, which solves the angle tilt problem of the target character area of the axis end image. To handle the various types of axis end markers and the small amount of data, a retraining method to improve recognition accuracy is proposed. This method first uses Chi_Sim as the basic font for training and then retrains based on the trained font. Finally, Tesseract-OCR is used to improve the accuracy of the recognition results. Experiments are carried out by developing an automatic recognition program for axle end marks. The results show that the proposed method can effectively identify and classify seven-character types, and the recognition accuracy reaches 96.88% while the recognition time of each image is 5.88 s.

A Practical Design Guide for Unbonded Jointed Plain Concrete Roads over Deteriorated HMA Roads: Realistic Traffic Loading

This study aimed to determine the material properties and the thickness of the layers of an unbonded jointed plain concrete pavement design over a deteriorated flexible pavement that lost its service capability. Maximum principal stresses occurring under the concrete pavement should not exceed the modulus of rupture of the concrete. Three-dimensional finite element analyses using ANSYS (Release 18.1 SAS IP, Inc.) software were carried out with the Taguchi method. The most reliable solution for the pavement design was investigated with whole configuration axle loading that reflects the realistic traffic situation. The stress values under the concrete slab due to the positive temperature gradient neglected in the American Association of State Highway and Transportation Officials (AASHTO) method were also investigated. The concrete slabs are exposed to these stresses for longer than the axle loads. Temperature distributions throughout the thickness of the concrete slab were calculated with the bilinear formulas suggested in the study. Axle loadings were applied on both the pavement edge and corner to reflect the most critical loading condition in the pavement design. The critical axle type was found to be 1.2. It was observed that a 0.15 m concrete thickness was appropriate for the concrete class, joint spacing and hot mix asphalt (HMA) elasticity modulus levels used for the 1.22, 1.122, and 1.2 + 111 axle types, but it was not appropriate for the 1.2 axle types. The slab thicknesses calculated with the AASHTO method, and the finite element method were found to be close to each other. It was determined that the concrete thickness significantly affected the maximum principal stress, with a performance statistic (S/N) value of 1692 for the 1.2 axle type. This was followed by the modulus of elasticity of the concrete with an S/N value of 0.356, the modulus of elasticity of the existing flexible pavement with an S/N value of 0.244, and the concrete joint spacing with an S/N value of 0.105. A practical design guide was recommended to extend the service life of a highly deteriorated flexible pavement with the construction of unbonded jointed plain concrete.

An Empirical Tire-Wear Model for Heavy-Goods Vehicles

ABSTRACT Tire selection has an important impact on the operational costs of heavy-goods vehicles (HGVs). HGV tires are designed on a tradeoff between wear resistance, rolling resistance, and adhesion (skid resistance). High wear resistance tires (high mileage) are replaced less often but use more fuel during operation, and vice versa for low rolling resistance tires. Presently, finding the optimal tire to minimize replacement costs and fuel consumption (greenhouse gas emissions) is challenging due to the difficulty in predicting tire wear for a given operation, since its rate varies with different vehicle configurations (e.g., load, vehicle length, number of axles, type of axle, etc.) and road types (e.g., motorways/highways, minor roads, urban roads, etc.). This article presents a novel empirical tire-wear model that can be used to predict the wear for multi-axle vehicles based on route data and a vehicle model. The first part of the article presents the analytical and experimental development of the model. The second part presents the experimental validation of the model based on 10 months of in-service data totaling 37,000 km of operation. The model predicts tire tread depth within 8% (average error of 2%).

Calculation of Equivalent Axle Load Factor Based on Artificial Intelligence

In most road pavements design methods, a solution is required to transform the traffic spectrum to standard axle load with using equivalent axle load factor (EALF). The EALF depends on various parameters, but in existing design methods, only the axle type (single, tandem, and tridem) and pavement structure number were considered. Also, the EALF only determined for experimental axles and axle details (i.e., axle weight, length, pressure), wheel type (single or dual wheel) plus pavement properties were overlooked which may cause inaccuracy and unusable for the new axle. This paper presented a developed model based on Artificial Neural Network (ANN) for calculation of EALFs considering axle type, axle length, contact area, pavement structure number (SN), tire pressure, speed, and final serviceability. Backpropagation architecture was selected for the model for the EALF prediction based on fatigue criteria. Finally, among all reviewed ANN configuration, a network with 7-13-1 was selected for the optimum network.

Mechanistic-empirical analysis of asphalt pavement fatigue cracking under vehicular dynamic loads

Vehicle-pavement interaction causes dynamic loads and accelerate pavement deterioration. The study provides a methodology to consider dynamic loads in mechanistic-empirical (M-E) pavement design and analysis. The dynamic load coefficients were found increasing as pavement roughness increased or axle loads decreased. The impulse response method was adopted to calculate tensile strains of asphalt layer under random loads. The relative ratios of fatigue life due to dynamic loads were calculated and fitted as a function of axle type, load magnitude, and international roughness index (IRI). The accumulative fatigue damage ratio between dynamic and static loads was proposed for M-E pavement analysis.

Influence of overloaded vehicles on pavement life based on WIM data

In this paper, the weight distribution characteristics of overloaded vehicles and the influence of overloaded vehicles on pavement service life are studied based on WIM data. Based on the vehicle weight data collected from weight in motion station, the vehicle weight distribution function of different axle type trucks and the weight overload ratio distribution function of different axle types are obtained by fitting. Equivalent single axle loads of the pavement under different weight limits are calculated based on the vehicle weight distribution function, and finally the pavement life growth factors under different weight limits are determined. The calculation results show that: the maximum overload ratio of two-axle vehicle can reach 340%; the number of six-axle overloaded vehicle accounts for more than 50% of the total number of overloaded vehicles, which is the largest proportion. Pavement life can be improved effectively by limiting load, and the road life growth factor shows a quadratic parabolic trend to increase with the decrease of load limit value. For two axle trucks with serious overload, the pavement life can be increased by more than 15 times with a strict load limit value.

HAVE TRACTOR MANUFACTURERS BORE IN MIND SOIL COMPACTION OVER THE LAST 40 YEARS?

Soil compaction is the compression of soil particles in a lower volume as a consequence of the reduction of the spaces existing among the particles themselves. This phenomenon is caused by natural forces and, above all, human ones. In order to estimate the field damages that can be caused by the traffic of agricultural machines, the load and the mean pressure applied by the tyres onto the soil can be measured. The research aim is to determine the pressure applied by each considered tractor onto the soil, in order to evaluate the effect of the traffic of tractors onto the soil itself. A total of 783 wheeled tractors manufactured and marketed in the last 35 years (1979-2014) were investigated. Data like construction year, manufacturer, model, power, total weight, weight (load) on the front and rear axle, wheelbase, front and rear type of tyres, as well as the tyre specifications, were collected. The mean pressure applied by each tractor onto the soil was computed by dividing the load applied on each tyre by its contact area. In order to reduce the pressure applied by agricultural machines onto the soil, the vehicle mass and, therefore weight, has to be reduced, or the tyre contact area on the soil has to be increased. Farmers can easily increase the tyre contact area, by decreasing the tyre inflation pressure or increasing the tyre width, i.e. mounting tyres having a larger section width, or Terra Tyres, or twin-tyres. Over the last 40 years: the mean power of mechanical four wheel drive (MFWD) tractors and four wheel drive (4WD) (isodiametric tyres) tractors increased, while that of two wheel drive (2WD) tractors remained constant; the power and the total weight increased, while the weight-power ratio decreased. Practically the reduction of the mean pressure on the soil resulted rather limited, meaning that tractor manufacturers have not bore in mind soil compaction.

Linking Traffic Volume and Weight Data for Mechanistic-Empirical Pavement Design

Pavement engineers are now practicing the cluster method to categorize routes by grouping them based on the similarity of their axle load spectra (ALSs). Ideally, once clusters are formed, a classification model needs to be developed with the help of site-specific attributes to assign a new site to an appropriate cluster. Still, there is no straightforward model that can relate the clustered ALSs with the easily collectible information, such as routes’ types or traffic volume data. To this end, this study developed a new ALS database based on the routes’ functional classes, locations, and vehicle class distribution (VCD) data. In the beginning, the routes were divided into six groups on the basis of their locations and functional classes. After that, this study performed a cluster analysis to split the routes of each group into an optimum number of subgroups considering both ALSs and VCDs of those routes. Finally, the representative ALS of each subgroup was calculated by averaging the site-specific ALSs of routes belonging to that subgroup. It is found that the absolute error computed for the proposed ALS database with respect to site-specific ALSs is lower than the existing methods. The observations and findings are based on the tandem axle of the single-trailer truck, which can be applicable to other axle types.

Analysis of Residential Space Structure Based on Housing Price in Lanzhou City

Based on the residential POI (Point of Interest) data in the central district of Lanzhou, the spatial pattern of housing price were discussed using spatial auto correlation analysis. The results show that: the spatial variation of residence price in Lanzhou presented a point axle type pattern with the east-high and west-low feature. The spatial dependence and anisotropy were apparent in spatial variability of housing price, housing price in different directions have different degrees of spatial autocorrelation. Furthermore, with the increase of variation, the influence of structural components, such as traffic, environment and public service, were becoming more and more significant.

Visual analytics towards axle health of high-speed train based on large-scale scatter image

Axle is an important part of high-speed train. The axle is the key component connecting the train wheelset, which has a great impact on the train safety. The health monitoring of axles is very important for the safe and smooth operation of trains. The axle health detection is a complex process of multi-factor coupling, which faces the problems of health model construction. From the perspective of big data visual analysis, this paper helps people find the information behind the big data of high-speed railway axle monitoring, and makes a prediction and analysis of the health status of high-speed railway axle operation. Starting from the present situation of scatter plot presentation of multi-dimensional data visual analysis, this paper proposes a visual analysis and processing method for high-speed train axle health monitoring, aiming at the problems of intensive rendering, visual mutation and trend prediction when drawing large data scatter plot. Firstly, a new method of the axle data fusion model is proposed in this paper, which can effectively clean the axle health monitoring data and construct the data acquisition and expression mode of axle temperature of high-speed train. Then, visualization of axle data and prediction of axle health trend provide a new analysis model for axle health monitoring. In addition, the visual analysis method of scatter density map data can eliminate the dependence of the original complex mechanical model, and can be used to analyze different working conditions and axle types. Compared with the existing axle health monitoring methods, this method has high accuracy and practicability.

Analysis of Transverse Cracks Forming in a Railway Axle

Surface defect is the main form of axle failure. In this paper, the cause of surface defect on wheel seat of a certain type of dynamic axle is analyzed systematically. In the test, the macroscopic chemical component of inspection axle was determined using spectrometer. And the chemical composition near the crack was detected by energy disperse spectroscopy and X-ray photoelectron spectroscopy analysis. The microstructure of the crack area was observed by optical microscope, while the crack microscopic characteristic was characterized using scanning electron microscope and confocal laser scanning microscope. The study found that, the defect is transverse crack, which was distributed circumferentially along the wheel seat. Further more, the typical features of wear or friction and iron oxide was observed on the wheel seat near the crack area. It was concluded that, due to surface presure and the existence of stress concentration, which the wheel and axle interference fit resulted in, wear abrasion and fretting fatigue initiated fatigue crack.

Estimation of stress at interface of asphalt surface and rigid base of composite pavement

Composite pavement, with asphalt overlaid on rigid base, can achieve a great structural advantage if interfacial bonding between the two layers can be maintained. If the interfacial stress exceeds the bonding strength of the tack coat material, the asphalt surface and rigid base can become debonded. Once debonding occurs, a high level of tensile stress will develop beneath the asphalt layer under traffic loading and subsequent development of cracks will occur. Conventional concrete, roller-compacted concrete and cement-treated concrete can be used as the rigid base of composite pavement and curling in this layer may lead to normal tensile stress at the interface. In addition, traffic loading as well as braking at the surface may develop the shear stress at the interface. These interfacial stresses are needed to evaluate bonding efficiency. Therefore, this study estimates numerically the interfacial tensile and shear stress due to the temperature differential in the rigid base and due to traffic loading, respectively. The study found that stress due to traffic loading is more important than that due to temperature differential. The tensile stress produced by curling in the rigid base can range from 0·05 to 0·16 MPa. Also, the combination of vertical and horizontal loading of various axle types can generate shear stress from 0·02 to 0·56 MPa.

АНАЛИТИЧЕСКОЕ ОПРЕДЕЛЕНИЕ НАПРЯЖЕННОГО СОСТОЯНИЯ ЦИЛИНДРИЧЕСКИХ ДЕТАЛЕЙ ПРИ ПОПЕРЕЧНОЙ ОБКАТКЕ ПЛОСКИМИ ПЛИТАМИ

The PURPOSE of the paper is to determine the stress state and the plastic deformation zone of cylindrical parts under transverse burnishing by flat plates. METHODS. The mathematical apparatus based on the laws of the theory of elastico-plastic solid is used in the work. RESULTS AND THEIR DISCUSSION. We have obtained analytical dependences for the determination of the stress components and the zone of plastic deformation under transverse burnishing by flat plates. The calculation results have shown that there is a stressed state of dilatation in the center of the workpiece cross-section and there is a stressed state of compression in the workpiece shell after the transverse burnishing. The depth of the plastic deformation zone depends on the degree of percentage reduction and the coefficient of friction between the workpiece and the plates. CONCLUSIONS. It is proposed to use the method of transverse burnishing by flat plates to harden low rigid cylindrical parts of the shaft and axle type. The developed mathematical model provides quite reliable values of the stressed state of the plastic deformation zone. The radius of the elastic deformation zone depends on the degree of percentage reduction and the coefficient of friction between the workpiece and the plates when transverse burnishing by flat plates. The hardening method employing transverse burnishing by flat plates eliminates cracking and material breakage in the central region of cylindrical products.

Новые способы поверхностного пластического деформирования цилиндрических деталей машин малой жесткости

Technological potentialities at finish-strengthening processing of low-rigid parts of shaft- and axle types with local ways of machining impact are rather limited. In the paper there are considered new ways for strengthening allowing obtaining qualitative surface strengthening in machine parts at high productivity of an engineering procedure.