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Rail traction and resistance play an essential role in the efficient operation of rail systems. The nature of traction is based on the balance between static friction and generated force at the perimeter of the driving wheels. The main objective of this paper is the development of a methodology and a modeling procedure for the design of train speed trajectory diagrams for the suburban railway. The model is applied to the Athens–Chalkida railway line (in Greece). For this purpose, geometric data for the above-mentioned railway line is collected from the Hellenic Railways Organization (OSE) and then recorded and digitized. A code is developed in MATLAB to calculate the total resistance of the railway line at each kilometer position. The traction elements of the trains operating on the Athens–Chalkida–Athens line, as well as other representative trains, and the magnitudes of their mechanical-aerodynamic resistances are recorded. The MATLAB program generates and compiles the train speed trajectory diagrams and the traction-resistance matrices. Finally, a comparison is made between the time, energy, CO2 emissions, and fuel costs of the rail in relation to the competing mode of transportation, which, for the specific line studied, is the tourist bus. [ABSTRACT FROM AUTHOR]

Rail traction and resistance play an essential role in the efficient operation of rail systems. The nature of traction is based on the balance between static friction and generated force at the perimeter of the driving wheels. The main objective of this paper is the development of a methodology and a modeling procedure for the design of train speed trajectory diagrams for the suburban railway. The model is applied to the Athens–Chalkida railway line (in Greece). For this purpose, geometric data for the above-mentioned railway line is collected from the Hellenic Railways Organization (OSE) and then recorded and digitized. A code is developed in MATLAB to calculate the total resistance of the railway line at each kilometer position. The traction elements of the trains operating on the Athens–Chalkida–Athens line, as well as other representative trains, and the magnitudes of their mechanical-aerodynamic resistances are recorded. The MATLAB program generates and compiles the train speed trajectory diagrams and the traction-resistance matrices. Finally, a comparison is made between the time, energy, CO2 emissions, and fuel costs of the rail in relation to the competing mode of transportation, which, for the specific line studied, is the tourist bus.

Dynamic orthoses have a significant effect on the treatment of elbow capsular contracture. Because of the lack of quantitative research on traction forces, determining the appropriate traction force to help stretch soft tissues and maintain the joint's range of motion is a challenge in the rehabilitation process. We developed a human elbow finite element (FE) model incorporating the activity behavior of the muscles and considering different capsular contracture locations, including total, anterior and posterior capsular contractures, to analyze the internal biomechanical responses of different capsular contracture models during flexion (30 to 80 degrees). Traction loads of 10, 20, 30 and 40 N were applied to the ulna and radius at the maximum flexion angle (80 degrees) to explore the appropriate traction loads at week 4 after a joint capsule injury. We observed a significant increase in posterior capsule stress with anterior capsular contracture (ACC), and the maximum peak stress was 1.3 times higher than that in the healthy model. During the fourth week after elbow capsule injury, the appropriate traction forces for total capsule contracture (TCC), ACC and posterior capsule contracture (PCC) were 20, 10 and 20 N, respectively; these forces maintained a stable biomechanical environment for the elbow joint and achieved a soft tissue pulling effect, thus increasing elbow mobility. The results can be used as a quantitative guide for the rehabilitation physicians to determine the traction load for a specific patient.

This study delves into an in-depth exploration of tractor tire performance on soft ground, with a specific focus on the intricate relationships between shear stress, slip displacement, and net traction. Leveraging a meticulously designed Tire Testing Machine (TTM) tailored for laboratory-scale analyses, the study systematically investigates three distinct tread depths of tractor tires. The TTM's unique capability to exert precise control over environmental conditions during tire compression and rolling on a designated soil surface underscores the methodological rigor of the investigation. Throughout the study, rigorous measurements of traction force, compression load, and vertical displacement were conducted to rigorously validate pressure-sinkage and net traction equations. A thorough analysis illuminates inherent errors and limitations within prevailing prediction models, providing a critical foundation for the refinement of future equations. The acquired experimental data not only offer indispensable insights guiding the development of more accurate predictive models but also establish a benchmark for the validation of finite element models in subsequent research endeavors. This work significantly contributes to the nuanced understanding of tire dynamics on soft ground, emphasizing the pivotal role of the TTM in ensuring a controlled environment for obtaining reliable experimental data. The delineated findings and limitations not only enrich the engineering discourse but also set the stage for ongoing research endeavors aimed at advancing predictive models and elevating our understanding of tire dynamics in the context of agricultural machinery navigating challenging terrains. [ABSTRACT FROM AUTHOR]

An original technical solution is proposed that permits the application of a main fertilizer dose once in 4-5 years at a depth of 6-25 cm with an inclined belt. The work aims to investigate the interaction between the proposed working tool (ripper-distributor) of the developed chisel-fertilizer with the soil, and to determine dependences that link its traction force with the design parameters. Studying the soil deformation pattern under the influence of working tool cutting parts based on classical mechanics made it possible to determine the dependence between the tractive force of the ripper-distributor and its design parameters. 3D modeling and C.F.D. analysis by using SolidWorks Flow Simulation® made it possible to define the fertilizer distributor parameters of the working body and flow characteristics of fertilizers. The distribution quality studies of fertilizer granules in compartments of the working tool distributor showed that the non-uniformity of distribution at different dosages (from 50 to 400 kg/ha) ranges from 7.8% for the application of granulated superphosphate up to 22.7% for the application of powdered superphosphate. The chisel-fertilizer enables soil-friendly and sloping site-specific fertilizer application at a depth from 5.6-9.8, 16-18, 23-25.8 cm, and a fertilizer distribution non-uniformity of 14-15% over the width of the spreader.

Introduction. Improving the traction and adhesion properties of freight electric locomotives is currently an urgent issue for the domestic locomotive industry. The increase in the mass and speed of trains enables to seek new ways and possibilities for realising the maximum tractive force of freight locomotives in order to meet the requirements of the rapidly developing transportation methods.Materials and methods. The authors carries out the analysis of existing theoretical and practical methods of adhesion control and developed the algorithm for controlling the wheelsets adhesion of a locomotive with asynchronous traction motors.Results. The authors concerning the tests analysis of a real electric locomotive, developed a mathematical model of the locomotive movement, which included algorithms for axial control of the tractive force with the redistribution of the tractive force between the axles. Calculations of a mathematical model of the movement of a locomotive with a train on a section with the redistribution algorithm both enabled and disabled, as well as with various settings of this algorithm, were carried out. The model also took into account the change in the adhesion coefficient of the wheels with the rails depending on the numerical order of a wheelset in the direction of travel, as well as the additional loading and unloading forces that arise in the undercarriage depending on the tractive force being realised. As a result of the calculations, obtained data showed good convergence with the test data of a real electric locomotive.Discussion and conclusion. The developed mathematical model allows evaluating the realisation of the tractive force of a locomotive as close as possible to that specified by the locomotive throttle under conditions of a changing adhesion coefficient and its heterogeneity under different wheelsets of the locomotive. The obtained results can be further applied in the development of promising freight electric locomotives with asynchronous traction motors.

An original technical solution is proposed that permits the application of a main fertilizer dose once in 4-5 years at a depth of 6-25 cm with an inclined belt. The work aims to investigate the interaction between the proposed working tool (ripper-distributor) of the developed chiselfertilizer with the soil, and to determine dependences that link its traction force with the design parameters. Studying the soil deformation pattern under the influence of working tool cutting parts based on classical mechanics made it possible to determine the dependence between the tractive force of the ripper-distributor and its design parameters. 3D modeling and C.F.D. analysis by using SolidWorks Flow Simulation® made it possible to define the fertilizer distributor parameters of the working body and flow characteristics of fertilizers. The distribution quality studies of fertilizer granules in compartments of the working tool distributor showed that the non-uniformity of distribution at different dosages (from 50 to 400 kg/ha) ranges from 7.8% for the application of granulated superphosphate up to 22.7% for the application of powdered superphosphate. The chisel-fertilizer enables soil-friendly and sloping site-specific fertilizer application at a depth from 5.6-9.8, 16-18, 23-25.8 cm, and a fertilizer distribution non-uniformity of 14-15% over the width of the spreader. [ABSTRACT FROM AUTHOR]

A study was carried out to analyse the enhanced power and torque characteristics of a diesel engine based tracked vehicle by hybridization of a conventional Internal Combustion Diesel Engine (ICE) with Electric System. A methodology is developed to simulate and validate tractive force and peak power requirement for a given drive cycle (sample drive cycle of 0 to 60 km/h in 61s considered). The performance enhancement was analysed in two different parallel hybrid configurations (EM before and after transmission - Modes 1 and 2 respectively). The existing ICE's power (221 kW) and torque (1030 N-m) was not altered and different Electric Motor (EM) ratings were considered as inputs for Degree of Hybridisation (DoH) (22 kW EM and 50 kW EM power with 72.5 N-m and 167 N-m of torque respectively). The hybrid system performance (with ICE and 50 kW EM) is notably enhanced to a maximum power of 290 kW and torque of 1274 N-m. The result indicates maximum improvement was achieved in Mode 2 configuration (5th gear with ratio 4.24: 1) as 22% and 38% power output improvement (11% and 24% Torque improvement) with 17.3% and 32.3% DoH respectively. [ABSTRACT FROM AUTHOR]

Introduction. When carrying out an energy assessment of agricultural machines and traction tests of tractors, the most important indicator is the value of the tractive effort. The existing methods for determining the tractive effort of tractors imply the use of specialized measuring instruments, such as strain gauges and devices for processing and displaying information. The accuracy of determining the tractive effort is significantly influenced by the physical and mechanical properties of soil. To process the useful signal during the measurement of tractive effort, the data stream of the strain gauge sensor must be subjected to additional digital filtering taking into account the operating conditions of the agricultural unit. Materials and Methods. The functions of changing the tractive effort obtained on the K-744R2 tractor in various gears have been analyzed. An algorithm for digital processing of the signal of a strain gauge force meter based on a median filter has been developed that makes it possible to increase the measurement accuracy. The advantage of the proposed method is the ability to cut off sharp short-term impulse noise and sharp fluctuations in the amplitude of the measured value. Results. A method for determining the amount of tractive effort using median signal processing has been proposed. A device for determining the tractive effort during testing of agricultural tractors and units has been developed. The choice of the main components of the device for determining the magnitude of the tractive effort has been substantiated. As a result of the research, a device for measuring and digital processing of the signal of a force meter based on a microcontroller and specialized software for processing initial data in real time was designed and manufactured. Discussion and Conclusion. The developed method makes it possible to exclude the negative effect of impulse noise arising in the process of measuring the tractive effort of the tractor. The proposed device for measuring the tractive effort of tractors is compatible at the level of the exchange protocol with existing devices, has a high speed of operation in real time, multi-channel operation.

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The movement conditions experienced by an agricultural gantry system along the solid and level ground surface of permanent artificial tracks must make it possible to generate most of its maximum tractive force. Concurrently, the adhesive ability of the agricultural gantry system on the ground surface of such permanent artificial tracks must be sufficient to generate nominal drawbar pull when working at a certain level of slip. This means that there exists the need to seek out the following compromise: the maximum slippage experienced by the wheeled chassis of an agricultural gantry system must be such that, in a situation in which the level of adhesion with the surface of permanent artificial tracks is suitable, it will be able to generate the maximum possible tractive force. The effect of the parameters that involve an agricultural gantry system's wheels – and the physical and mechanical properties of the ground surface along which they move – on potential slippage has not yet been sufficiently studied. This effect cannot be taken into consideration without taking into account the dynamics of any rolling resistance being offered by the agricultural gantry system's chassis. The purpose of this particular study is to research the traction properties of an agricultural gantry system's wheeled chassis in terms of its movement along compacted and level ground upon which have been mounted permanent artificial tracks. The research determines that the wheels of such an agricultural gantry system that are rolling along permanent artificial tracks suffer less slippage and therefore generate a higher level of tractive force. As a result, the agricultural gantry system loses less of its speed of movement and, therefore, uses less energy in that movement. When an agricultural gantry system moves across an agricultural field that has been prepared for sowing, the research also determines the maximum tractive force that its wheels can develop when the adhesion coefficient is set at a figure that is between 0.22–0.24. Once such movement begins along permanent artificial tracks, this coefficient decreases to between 0.15–0.17. An agricultural gantry system's wheels are able to generate a higher level of tractive force when moving along on permanent artificial tracks. This figure is at least 30% higher when its movement has to be considered across an agricultural field that has been prepared for sowing.

The features of the traction and dynamic analysis for mobile robots with propulsors discretely interacting with the support surface in general and with walking propulsors in particular are substantiated. The design parameters of a robot and the controlling actions affecting the energy efficiency of motion are determined. The application of the proposed method of analysis to the estimations of heat losses in the developed Ortonog robot is considered. Generalization of the result obtained made it possible to establish the critical motion velocities that ensure the maximum efficiency of robots with propulsors of the types considered. [ABSTRACT FROM AUTHOR]

A mechatronic-based embedded system was used to measure and display the dynamic wheel axle torque and tractive force of different tractor-implement combinations. It included a special transducer to measure drive wheel torque of a tractor, and an embedded telemetry digital system to receive, process and record the data in SD card module. The observed dynamic wheel axle torque under various tillage operations using different implements were compared with the theoretical values using traction models of Brixius (1987), Wismer and Luth (1973) and Tiwari (2006) to find the model suitable for sandy clay loam soils. The results were compared using the gross traction ratio and motion resistance ratio. Maximum variation of (+) 35% was observed between the developed system and the theoretical calculated values using Brixius (1987) and Wismer and Luth (1973) models, while Tiwari (2006) model had maximum variation of (+)14 per cent.

The movement conditions experienced by an agricultural gantry system along the solid and level ground surface of permanent artificial tracks must make it possible to generate most of its maximum tractive force. Concurrently, the adhesive ability of the agricultural gantry system on the ground surface of such permanent artificial tracks must be sufficient to generate nominal drawbar pull when working at a certain level of slip. This means that there exists the need to seek out the following compromise: the maximum slippage experienced by the wheeled chassis of an agricultural gantry system must be such that, in a situation in which the level of adhesion with the surface of permanent artificial tracks is suitable, it will be able to generate the maximum possible tractive force. The effect of the parameters that involve an agricultural gantry system's wheels - and the physical and mechanical properties of the ground surface along which they move - on potential slippage has not yet been sufficiently studied. This effect cannot be taken into consideration without taking into account the dynamics of any rolling resistance being offered by the agricultural gantry system's chassis. The purpose of this particular study is to research the traction properties of an agricultural gantry system's wheeled chassis in terms of its movement along compacted and level ground upon which have been mounted permanent artificial tracks. The research determines that the wheels of such an agricultural gantry system that are rolling along permanent artificial tracks suffer less slippage and therefore generate a higher level of tractive force. As a result, the agricultural gantry system loses less of its speed of movement and, therefore, uses less energy in that movement. When an agricultural gantry system moves across an agricultural field that has been prepared for sowing, the research also determines the maximum tractive force that its wheels can develop when the adhesion coefficient is set at a figure that is between 0.22-0.24. Once such movement begins along permanent artificial tracks, this coefficient decreases to between 0.15-0.17. An agricultural gantry system's wheels are able to generate a higher level of tractive force when moving along on permanent artificial tracks. This figure is at least 30% higher when its movement has to be considered across an agricultural field that has been prepared for sowing. [ABSTRACT FROM AUTHOR]

Mechanical methods of weeding are preferred over other methods of weed control because of their added advantages of simple construction, low cost and environmental friendly. Mechatronics concept was incorporated in development of a battery-assisted four-wheel weeder for weeding operation in wide row (more than 30 cm) crops. The developed machine consisted of brushed DC motor, DMSC, battery, power transmission system, drive-wheels, front wheels, frame and swinging handle. A brushed DC motor of 250W powered by 24V-14Ah battery with sweep type weeding tool performed satisfactorily in the field for weeding operation up to 147N draft.The operators are to only guide the weeder up to 147N draft while they need to apply their muscle power beyond 147N to prevent slippage.The average field capacity with this machine was 0.0554 ha/h at walking speed of 2.52 km/h with 97.5% weeding efficiency. The machine is gender-friendly with simple in design and technology and has potential to be adopted by small and hill farmers with reduced drudgery. The concept of transforming manual operated to battery assisted weeder was found satisfactory for wide row crops.

Dynamic orthoses have a significant effect on the treatment of elbow capsular contracture. Because of the lack of quantitative research on traction forces, determining the appropriate traction force to help stretch soft tissues and maintain the joint's range of motion is a challenge in the rehabilitation process. We developed a human elbow finite element (FE) model incorporating the activity behavior of the muscles and considering different capsular contracture locations, including total, anterior and posterior capsular contractures, to analyze the internal biomechanical responses of different capsular contracture models during flexion (30 to 80 degrees). Traction loads of 10, 20, 30 and 40 N were applied to the ulna and radius at the maximum flexion angle (80 degrees) to explore the appropriate traction loads at week 4 after a joint capsule injury. We observed a significant increase in posterior capsule stress with anterior capsular contracture (ACC), and the maximum peak stress was 1.3 times higher than that in the healthy model. During the fourth week after elbow capsule injury, the appropriate traction forces for total capsule contracture (TCC), ACC and posterior capsule contracture (PCC) were 20, 10 and 20 N, respectively; these forces maintained a stable biomechanical environment for the elbow joint and achieved a soft tissue pulling effect, thus increasing elbow mobility. The results can be used as a quantitative guide for the rehabilitation physicians to determine the traction load for a specific patient.

The game of football enjoys high popularity worldwide and has undergone significant changes in terms of the players’ physical strain. This study seeks to analyze the differences that may occur at the level of the tractive force between two junior groups: one of 15-16 years (n = 21, 177.5 ± 5.98 cm height, body mass 68.53 ± 6.28 cm) and one of 17-18 years (n = 24, 175.3 cm ± 8.27 height, 61.93 ± 8.61 cm body mass). The tractive force was measured with an Axis FB5k dynamometer, adapted to such an assessment by the various accessories. Four tractive forces were evaluated: forward, backward, left and right. We assumed that the values of the tractive force would be different between the two age groups. The highest values within each group were noticed in the case of the forward tractive force (62.63 ± 8.39 kgf) of the 17-18 years old players and the right tractive force (58.51 ± 13.09 kgf) of those 15-16 years. The hypothesis of the study was invalidated by statistically insignificant differences that have emerged in each measurement.

A typical feature of rail corrugation on metro rails is the almost 100% probability that low rails on sharply curved tracks will suffer from corrugation, but both high and low rails on gently curved tracks are less prone to corrugation. On Chongqing Metro Line 10, there is a curved track on an ascending slope, and the high rail of this track suffered from severe corrugation. Shenzhen Metro Line 3 has a curved track on a descending slope, and the low rail of this track was also subjected to corrugation. This article presents a study on the rail corrugation formed on metro ramps. Two vehicle-track coupled dynamic models were employed to judge whether the creep force in the contact patch would be saturated, with results showing that the creep force of the leading wheel on the high rail on the uphill section tends to be saturated, affected by the tractive force. Influenced by the braking force, the creep force on the leading inner wheel on the downhill section is also prone to be saturated. In this study, the formation of corrugation is attributed to the self-excited oscillation generated at the wheel-rail (W-R) interface. Based on this mechanism, a finite element model for predicting the occurrence propensity of the low rail corrugation on the downhill track was developed. The simulation results show that increasing lateral fastener damping is beneficial for suppressing rail corrugation. • The inner wheel will slide on the low rail on the downhill track. • The outer wheel will slide on the high rail on the uphill track. • Complex eigenvalue analysis is applied to predict self-excited vibrations. • Self-excited vibration at 304 Hz causes low rail corrugation on the downhill track. • Selecting the appropriate braking torque can reduce rail corrugation on the ramp. [ABSTRACT FROM AUTHOR]

Soil-vehicle interaction is an important factor for predicting trafficability of off-road vehicles. Tractive forces on the wheel to drive the vehicle can be estimated by soil deformation analysis around the contact area of the wheel. Sand deformation and flow under a rolling wheel with slippage were observed from the side through a transparent acrylic wall by 2-dimensional Particle Image Velocimetry (PIV) method. The flow velocities of sand particles obtained on allocated grids revealed that periodic fluctuations of sand flow make ripple patterns on the sand surface behind the wheel. We discussed the effect of wheel slip ratios on the density of the ripples, sinkage, drawbar pull, torque and the depth of influence for the traveling wheel. The result showed that the slipping wheel forms a ripple with each scratch by the wheel rotation corresponding to the front half contact length with sand. The thickness of sand flow layer under the wheel showed thinner for large slip ratios. The finite element method was also conducted to simulate the traveling wheel experiment to discuss the possibility of the numerical simulation. The result of simulation qualitatively reproduced the experiment. However, there was a quantitative difference on the drawbar pull of the wheel, which shows that the method needs modification on the numerical model.