Track Links Research Articles

ОБРАБОТКА ОТВЕРСТИЯ ОПОРНОГО РОЛИКА ХОДОВОЙ СИСТЕМЫ ТРАКТОРА ПРОШИВКОЙ

Restoring the surface of the roller treadmill to its nominal value using automatic surfacing technology makes it possible to obtain a significant surfacing layer with a sufficient degree of strength and wear resistance. At the same time, as a result of thermal action, the metal of the roller receives a linear shrinkage, due to which the diameter of the hole for the bearing of the roller axis decreases. In this case, it becomes impossible to install the outer bearing cage. (Research purpose) The research purpose is substantiating the method of processing the seat under the outer bearing cage after surfacing the treadmills of the support roller. (Materials and methods) It was noted that the surfaces of the treadmills of the support rollers wear out quickly as a result of abrasive friction with the track link and the soil. It was clarified that when surfacing in all ways, metal shrinkage occurs and the diameter of the hole for the outer bearing cage decreases. (Results and discussion) It was found that the wear of the treadmills of the support rollers averaged 13.9 millimeters. Restoration of the treadmill surface of the roller to the nominal value, carried out by the method of multilayer automatic surfacing, caused a decrease in the diameter of the roller opening by an average of 0.73 millimeters. We chose from the considered options for calibrating the hole the most preferable from and time-saving one, the firmware processing method. (Conclusions) The appearance of shrinkage of the support roller hole during restoration by automatic surfacing and the method of calibrating the hole using firmware were substantiated. The method provides tension in the coupling of the outer ring of the bearing with the roller within 0.015-0.039 millimeters and surface cleanliness within Ra 1.25-0.63 micrometers. The firmware is simple in design and can be manufactured in a repair shop.

To the question of improving the wear resistance of high manganese steel castings

Nowadays, one of the most significant tasks in production of equipment for mining industry is import substitution. In this regard, investigations aimed at improving the technologies of manufacturing high quality castings from wear resistance manganese austenitic steels seems to be relevant. The results of metallographic research of high manganese steel samples from foundries producing crushing plates and crushing cones, track links, hammers, shovel teeth, tooth caps etc. are given. Analysis of the microstructure of the presented castings showed that they are characterized by a coarse-grained structure with an austenite grain size of 1–2 points. In most cases, a thickened grain boundary, presence of manganese carbides along the grain boundaries and non-metallic inclusions are observed. The revealed mi-crostructure features of castings are one of the main indicators of low wear resistance of high manganese steel parts. The operational and technological factors affecting the wear resistance of castings are listed. Recommendations for improving the quality of steel products made from manganese steels are proposed, and the results of using original complex modifiers developed at NPP Technology Company in real manufacturing conditions are presented.

Susceptibility Modeling of a Rubber Track for Lightweight Mobile Robots

The elastic-damping properties of the rubber track structure can have a significant impact on the running gear performance of lightweight mobile robots. Taking these properties into account is particularly important for modeling obstacle negotiation and estimating the robot’s driving force. The article presents track susceptibility identification using both static and dynamic tests. The experimental results were used to validate the multi-body dynamics model of the rubber track for three modeling methods and for three track link number model variants. The methods and variants were compared by the accuracy of the susceptibility parameters obtained using them. The impact of the modeling methods on the track bending resistance simulations was also checked.

Technological equipment for foundry production, efficiency and safety

The article discusses the results of the development and research of controlled electrical preheating of casting troughs and intermediate tanks in the system of transport trays for pouring aluminum melt. Electric heating contributes to high-quality and safe pouring of the melt in the cold shop. The heating of the casting track links eliminates the possibility of an explosion when the melt contacts water or ice, and also maintains the fluidity of the metal and limits the temperature gradient in the melt. Evaluation of the efficiency of the heater system was carried out on the basis of mathematical modeling of thermohydrodynamic processes in the melt. Acceptable characteristics of the section of the trays were determined to improve the distribution of metal by the melting and casting complex. To ensure the electrical safety of the equipment, it is proposed to power the heaters at a reduced voltage. Changing the intensity of heating is implemented by switching the windings of a group of power transformers from a delta connection to a star connection. Preheating controls are built in the form of a relay-contactor subsystem integrated into the microcontroller control system of the foundry complex.

Study on Folding Defect Elimination Method of Track Link Forging Based on Preforming Design

Study on Folding Defect Elimination Method of Track Link Forging Based on Preforming Design

Dynamic Simulation Analysis of Track Tension and the Influencing Factors of Deep-Sea Tracked Mining Vehicle

The deep-sea mining miner requires good passability to operate in complex and changeable terrain environment of the seabed. Among them, the track tension is an important factor to ensure the normal running of the vehicle. Aiming at the complex track tension problem on track link, the forces on each component of the tracked system were analyzed, and the theoretical formulas of track tension were established. The theoretical estimation and dynamic simulation of track tension in uniform speed were carried out by using the multibody dynamics model of the tracked vehicle, and the rationality of the theoretical estimation formula was verified. The influencing factors of track tension also were analyzed, and the significance of each factor on track was discussed by dynamic simulation. The results provided a theoretical basis for design of tracked vehicles.

Optimization of the rubber element of the rubber-metal hinge of a tracked system

The paper presents the formulation of the problem of optimal design of rubber bush of the track link and its solution. The search for the optimal design is based on the results of calculating the stress-strain state of the rubber ring caused by the assembly of the rubber-metal hinge and loads during subsequent operation. As an objective function, the specific energy of deformation of the rubber was chosen. The dimensions of the rubber ring of the rubber-metal hinges in the undeformed state are taken as variable parameters. Formulation of the optimization problem imposes constraints on the design parameters in the form of inequations. The solution of the problem of optimal design and the results of durability tests are presented.

Reducing the soil structure destruction along the rut and increasing the traction properties of the tractor by using the rear grouser of the track link

The traditionally used mixed grouser of the metal track link causes a decrease in the traction qualities of the agricultural tractor. The use of a rear grouser on the track link, in our opinion, will significantly improve the traction properties of an agricultural tractor with a metal track and reduce the soil destruction. When the rear grouser is immersed in the soil, an additional horizontal deformation of the soil occurs, which changes the law of horizontal deformation distribution along the support surface of the trackdrive, which ensures the alignment of the link shares in the implementation of the tangential traction force. This leads not only to a reduction in the trackdrive skidding, but also to a reduction in tractor rolling losses. Comparative tests of the T-4A tractor with a serial track, and a track on which links the front grousers were removed showed that the maximum traction power increases from 59 to 65 kW, the skidding with a hook load of 40 kN decreases from 14.6 to 9.4%, the rolling resistance coefficient decreases from 0.093 to 0.072, eliminates the “scissors” effect, which will reduce the number of erosive-dangerous particles in the track trace to 30...40%, which is 5.6...4.25 times less than in agricultural tractors with a mixed grouser, which confirms the effectiveness of their use.

Failure Characteristics on ADNAN Malaysian Armoured Vehicle Track Shoe and its Improvements

Armoured military vehicle is designed to withstand the stresses impact from bullets, missiles or any explosive shells. It is applied to the vehicle in order to protect the personnel inside from enemy fire and also to protect from any threats other than deliberate attack. However, an issue arises when it comes for track link shoes of the armoured vehicle which already became problems to the designers and users of tracked vehicles. The track link problems usually related to the problems that already existed because of its excessive weight, excessive noise and vibrations, overheating of rubber track elements and road wheels, etc. All of these existing problems could leads to the failure of pin and bushing, chunking of the pads and breaking of the track links itself. Instead of that, today’s tracks are much more expensive not only in terms of initial cost but also the replacement cost. Here, this paper reviews some of the failure cases and improvements of the armoured-vehicle itself. It also covers a real study on the failure assessment of the ADNAN (The Malaysian Armoured-Vehicle) Track Shoe.

Multibody simulation of a tracked vehicle with deformable ground contact model

In this paper, the realisation of a multibody model of a tracked machine is described. A new compact modelling of the tracks–soil interaction is presented and soil mechanics laws for terrain response are implemented. Tracked vehicles can be used in different fields such as agriculture, military and construction. The conditions of the terrain on which they operate may vary a lot, in terms of soil composition, slope and roughness. For this reason, performance of tracked vehicles is difficult to predict without a great number of field tests. The model is developed in a multibody code that makes it possible to investigate its dynamic and kinematic behaviour in several operating conditions. A specific routine is implemented in the multibody model in order to simulate the behaviour of the tracked vehicle on deformable terrains. The main hypothesis of this paper is that the terrain deformation could be in a narrow zone affected by the vehicle. Thus, the deformation of the soil is kinematically correlated to the vehicle. Soil mechanics equations are implemented on each track portion and solved only for track links in contact with the soil. The latter is modelled as a rigid body and terrain stress or deformation are not directly computed, thus simplifying solution and terrain modelling despite obtaining coherent results in terms of vehicle traction force, slip and sinkage. Results are reported pointing out performance of the tracked machine on different ground conditions.

Quantitative evaluation of the effect of technological factors on origination of hot cracks in “track link” casting

Quantitative evaluation of the effect of technological factors on origination of hot cracks in “track link” casting

Probabilistic Modeling of Tracked Vehicle Mover And Ground Interaction

The article is devoted to ensuring the strength reliability of the tracked vehicle running gear. The method of estimation of track link fatigue life is proposed. The technique is based on the method of resource modeling at the design stage of the machine. The technique involves computer modeling of movement of the machine on the road, the calculation of loads acting on the track, stresses in the most loaded areas of tracks and forecasting of durability based on the fatigue failure criterion. The simulation accounts for the dynamic properties of the machine and the typical working conditions in a variety of natural and climatic conditions.The laws of track link loading are determined based on the results of field tests. The maximum stress in track link arises in the moments when the wheels pass on the track. The stress value and pulses signs depend on the dynamic loads from the road wheels and ground reactions, randomly distributed over the surface of the track.To calculate the loads acting on the track in the supporting part of a caterpillar, a ground model is proposed. The ground is regarded as a Winkler half-space with randomly distributed elastic elements, which interact with caterpillar track. The results of the ground model identification and the method of calculating the loads acting on the track are presented. The load change processes are then used to calculate the stresses in the most loaded areas of a track and to predict the fatigue life.

Evaluation of the accuracy of the rigid body approach in the prediction of the dynamic stresses of complex multibody systems

In this paper, the floating frame of reference and absolute nodal coordinate formulations (ANCF) are explained in detail and used in the stress analysis of the track links in a complex three-dimensional tracked vehicle model. One of the most common areas of failure for such tracked vehicles is attributed to the failure of the track link chains, and therefore, performing a detailed fully coupled stress analysis, as the one described in this investigation, is necessary in order to obtain more accurate stress results and avoid failure of such complex vehicle systems.

Modular Multibody Formulation for Simulating Off-Road Tracked Vehicles

This paper presents a formulation and procedure for incorporating the multibody dynamics analysis capability of tracked vehicles in large-scale multibody system. The proposed self-contained modular approach could be interfaced to any exiting multibody simulation code without need to alter the existing solver architecture. Each track is modeled as a super-component that can be treated separate from the main system. The super-component can be efficiently used in parallel processing environment to reduce the simulation time. In the super-component, each track-link is modeled as separate body with full 6 degrees of freedom (DoF). To improve the solution stability and efficiency, the joints between track links are modeled as complaint connection. The spatial algebra operator is used to express the motion quantities and develop the link’s nonlinear kinematic and dynamic equations of motion. The super-component interacts with the main system through contact forces between the track links and the driving sprocket, the support rollers and the idlers using self-contained force modules. Also, the super-component models the interaction with the terrain through force module that is flexible to include different track-soil models, different terrain geometries, and different soil properties. The interaction forces are expressed in the Cartesian system, applied to the link’s equation of motion and the corresponding bodies in the main system. For sake of completeness, this paper presents dynamic equations of motion of the links as well as the main system formulated using joint coordinates approach.

Design and Analysis of Double Wishbone Suspension Module with Wheel-Track Variant Wheels

Based on the new type of wheel-track variant wheel prototype which is developed independently and creatively, the paper focuses on several problems, including the severe wear of track links, the difficulty in steering under the form of track, and so on, and combines the characteristics of variant wheel, so as to design and analyze the positional parameters of variant wheel-double wishbone suspension module. Besides, through refitting the variant wheel based on a type of all terrain farmer truck (UTV), the paper builds a model for the kinematics analysis of UTV variant wheel—double wishbone suspension model, and takes the minimum of the weighed sum of changes in wheel alignment parameters and the lateral displacement of variant wheel which affect wheel wear and steering as the optimized objective, so as to carry out an optimization calculation for its suspension system. In addition to that, the paper modifies UTV based on the optimization results, solves the problems arising in the experiments of variant wheel, and provides theoretical support and references for the application of wheel-track variant wheel in other types of vehicles.

Mathematical modeling of thermal state of hollow track link pins’ workpieces

Mathematical model and numerical calculation results for the thermal state of cylindrical hollow track link pins’ workpiece are given. Numerical calculation results of heat exchange parameters depending on geometry, thermophysical properties and processing duration are analyzed.

Movability and reliability of parts and units of crawler machines’ running gear

The weight decrease possibility of single-functional crawler machines by means of tubular running gear parts (torque rod, track link pins) application and light alloys using is shown.

Selection of Protective Coatings of Moulds for Castings of High-Manganese Cast Steel in Dependence of the Applied Moulding Sand Kind

Abstract High-manganese cast steels are characterised by a high abrasion resistance under friction conditions with a simultaneous influence of pressure and impacts. This cast steel is especially suitable for castings of excavator’s scoops, track links, streetcars crossovers, parts of crushers and mills for braking up of hard materials [1-4]. In order to obtain high quality castings of high-manganese cast steels in moulds on the high-silica sand matrices it is necessary to apply protective coatings, which prevent a direct contact between metal and matrix (SiO2). Manganese after being poured into a mould can undergo a partial oxidation forming MnO, which reacts with silica. As a result low-melting manganese silicates are formed, which in a form of a tight layer adhere to the casting surface, significantly increasing a labour input related to cleaning. Three kinds of protective coatings were tested: zirconium, corundum and magnesite. As a base moulding sands on high-silica sand matrices with three kinds of resol resins were applied. The quality of the obtained casting surface was assessed in dependence of the protective coating and resin kind and also in dependence of the metallostatic pressure value.

Robust design optimization of the dynamic responses of a tracked vehicle system

This paper presents the robust design optimization of the dynamic responses of a heavy military tracked vehicle system. The tracked vehicle model addressed in this study has 954 degrees of freedom and consists of 189 bodies in total: 37 bodies for the chassis, such as sprockets, road wheels, road arms, etc.; 76 track link bodies for each track subsystem; 36 revolute joints; and 152 bushing elements. The design objectives were to minimize the maximum vertical acceleration of the hull and its variance while satisfying the wheel travel constraints for torsion bars and the hydro-pneumatic suspension units within ±1σ ranges. To avoid the difficulty of the design sensitivity analysis and to overcome the numerical noise, a progressive meta-model technique was employed in the optimization process. First, space-filling methods were used to determine the minimum number of sample points. Second, the simultaneous kriging method was used to construct the initial meta-models, and the augmented Lagrange multiplier (ALM) method was then used to solve the robust design problems of the meta-models. Third, the new design results were added to the analysis results for the initial sample points, and the meta-models were updated automatically. Next, the optimizer resolved the robust design problems of the updated meta-models. These processes were repeated until the convergence tolerances were satisfied. The robust design optimization of the tracked vehicle system, with 11 random design variables, was solved in only 26 analyses, including 12 analyses for the initial meta-models and 14 analyses added during the iterative optimization process.

Comparing load conditions of plane and false-ellipse running surface contours of track links in running gears for construction equipment

To improve durability and fatigue strength, it is advisable to give running surfaces of track links in undercarriages for construction equipment a false-ellipse profile. Such a profile resembles the contour of a running surface of a railway rail. Kinematic conditions as they exist for the track run in the undercarriage of construction equipment can however not be compared with those of a railway. Moreover, construction equipment in field operation is in particular faced with problems like lateral inclinations and misalignments between running surfaces of track link and bottom roller. For all this it is necessary to have a look at the load conditions of track links. This article makes clear that, above all with a view to the fact that in the past only plane running surface profiles were used for construction equipment applications, designing track link running surfaces with a false-ellipse profile has considerable advantages compared to plane running surfaces even at a misalignment ratio of just 1/5 of the maximum width of track link running surface.