Search

Truck suspension is a vital component supporting the weight of the vehicle body and plays an important role in transferring wheel load and isolating external vibration. The uneven load distribution between the middle and rear wheels of a tri-axle heavy truck will directly affect the driving stability and safety of the vehicle. To enhance the truck's wheel load distribution performance and ride comfort, this paper proposes a new coupling suspension system, including an anti-synchronous middle and rear axle hydraulically interconnected suspension (MR-HIS) and the front axle conventional independent suspension (CIS). Considering the load-bearing characteristics of the middle and rear wheels of the tri-axle heavy truck, a five-degree-of-freedom (5-DOF) half-vehicle model of the truck equipped with MR-HIS is constructed. Further, the dynamics equations of the mechanical-hydraulic coupling system are established according to the impedance transfer matrix method and mechanical-hydraulic boundary conditions, and the truck body motion modes are completely decoupled. The modal analysis demonstrates that compared with CIS the proposed MR-HIS system can reduce the body bounce modal stiffness, increase the modal damping ratio, and enhance the dynamic coupling performance of middle and rear wheels. Subsequently, the frequency response analysis is adopted to evaluate the load distribution and vibration isolation performance of the MR-HIS. The comparison analysis results indicate that the proposed MR-HIS system significantly improves the load balance distribution between the middle and rear wheels and suppresses the load transfer to the front wheel, thus the handling stability of the truck is improved. Meanwhile, the body vibration frequency response analysis shows that the MR-HIS can effectively isolate external vibration and improve driving comfort of the tri-axle heavy truck. [ABSTRACT FROM AUTHOR]

The article contains experimental evaluation of technological possibilities of the wave-shaped profiles and confirmation of classical metal flow on profiles of wheel rims with toroidal flanges. The following parameters are recorded during the experiments: temperature in the finishing gauge, rolling force in the 2nd, 4th, 6th and 7th passes, current, voltages and motor speeds. The analysis of experimental data of rolling profiles 7.0-20-03, 8.5-20-03 and 228G-020-01 shows that technological capabilities of special rolled products for the truck wheel rims with wavy central part are much higher than serial profiles, where the central zone is of rectangular shape. It is possible to reduce the mass of profiles without changing the process parameters, i.e., rolling force and torque. This indicates the influence of additional and kinematic effects on the deformation zone in real production conditions. [ABSTRACT FROM AUTHOR]

During the braking manoeuvre of a vehicle on a pavement, the mechanics associated with load transfer is complex due to the presence of slip, load shift between the front and rear axles, and development of longitudinal forces. The road profiles, braking intensity, truck mass, and speed during braking play a critical role here. This investigation reports an attempt to collect such data. A unique Hardware-in-Loop set-up was integrated with vehicle dynamics software, TruckMaker, to perform a realistic braking manoeuvre. Three truck loadings were chosen from the axle load survey conducted in the field (unladen, laden, and overloaded). Three ISO road profiles (A, B, C) generated using the power spectral density approach, three initial speeds (30, 50, and 80 km/h), and three braking intensities (Partial (10%), Partial (45%), and Complete (100%)) were chosen for the simulation. In total 81 simulations were performed considering all the above-said factors. From the analysis of wheel slip values, it was identified that the wheels of unladen trucks lock during complete braking, irrespective of the speeds and road profiles. The complete braking manoeuvre for all vehicle types showed more load shift from the rear axle to the front axle compared to partial braking manoeuvres. Also, the unladen trucks were found to transfer more percentage (>50%) of their rear axle load to the front axle during braking. The maximum longitudinal force developed at the tyre-pavement interface was found to be independent of the loading conditions during complete braking. [ABSTRACT FROM AUTHOR]

Under the interaction of the wheels of heavy-duty trucks on the random road surface when the vehicles are travelling, their generated vibrations not only affect the driver's ride comfort but also impact the road surface damage. To assess the vibration influence of different types of vehicles on the road surface damage, three dynamic models of the two axle, three axle, and four axle of heavy trucks have been build and computed via the Matlab/Simulink software. The dynamic tire load, dynamic load coefficient, and dynamic load-stress factor are chosen to assess the friendly load of different heavy trucks under the different operating conditions of the vehicle. The obtained result indicates that the dynamics parameters including suspension system, tires, and axle load distributions of heavy trucks have a greater effect on the dynamic tire force than the total weight of the vehicle. In order to ensure the road's safety, the traffic management should intervene quickly to give a velocity limit for vehicles under the condition of the vehicle moving with the empty loaded on the poor road surface. [ABSTRACT FROM AUTHOR]

This study reports the welded joint of a novel 590 MPa V-N microalloyed wheel steel on microstructure and mechanical properties after flash butt welding. The welding parameters were flash current 48°/582.0 A, upsetting current 44°/516.6 A, and workpiece clearance 1.5 mm. The evolution of microstructure in the welded joint occurred as follows: welding seam (ferrite side plate + acicular ferrite +martensite)→coarse-grained zone (acicular ferrite + granular bainite)→fine-grained zone (fine-grained ferrite + M/A island)→base metal (equiaxed ferrite + pearlite). The standard impact energy value of welding seam, coarse grain zone, fine grain zone, and base metal at −40 °C was 116, 128, 144, and 88 J, respectively. The mechanical property of the joint was excellent. The microstructure, the number of grain boundaries, and the dislocation density directly affected the strength and hardness of the joint. The increase of large angle grain boundaries and the decrease of effective grain size were beneficial to the improvement of toughness. The hot-rolled 590 MPa V-N microalloyed wheel steel had superior weldability. [ABSTRACT FROM AUTHOR]

The use of lightweight self-consolidating concrete (LWSCC) has significantly increased due to enhanced mix designs and its projected lower overall costs than normal-weight concrete. Accelerated bridge construction (ABC) has become a common alternative to conventional construction techniques. The use of LWSCC in ABC will reduce structural loads and expedite transportation and installation of precast bridge elements. Limited research, however, has investigated LWSCC bridge elements reinforced with glass fiber–reinforced polymer (GFRP) bars. This paper reports on the performance of full-scale edge-restrained bridge deck slabs (simulating slab-on-girder bridges) fabricated with LWSCC reinforced with GFRP bars. The test specimens included three edge-restrained slabs and one unrestrained slab for comparison. The test specimens were 3,000 mm long × 2,500 mm wide × 200 mm thick and were tested up to failure under a concentrated load simulating the footprint of a standard CL-625 truck wheel load (87.5 kN) defined in current design codes. The investigated parameters were (1) reinforcement ratio; (2) top reinforcement; and (3) effect of edge-restraining. The cracking behavior, ultimate capacity, deflection, and concrete and reinforcement strains of the specimens were presented and discussed. In addition, the punching-shear capacity of the tested specimens was assessed with the currently recommended design equations. The test results indicate that the overall performance of LWSCC deck slabs reinforced with GFRP bars is similar to such structures made with normal-weight concrete. [ABSTRACT FROM AUTHOR]

There are many accidents in road traffic involving both heavy goods vehicles and passenger vehicles, and the interpretation of the causes of some accidents can be very difficult. The paper presents the results of an analysis of the road accident causes involving a truck and two passenger cars. The hypothesis was verified that the incident took place after the damage to the front wheel of the truck, which resulted in an uncontrolled change of the direction of its travel and leaving the lane in the opposite direction of the passenger cars. The damaged tire was inspected, and traces were described in the form of cracks on the side surface, irregular abrasion on the central part of the side surface and near the bead, as well as deformations resulting from damage to the cord. The thesis was made that the tire cracked as a result of its material structure defects. In order to verify it, bench tests were carried out on the deformation of the tire sidewall at various load conditions, which simulated driving with too little air pressure in the tire. Detailed studies of the fracture of the tire sidewall and the wires that make up its steel cord were carried out. Macroscopic examination of the cord wires on eight samples revealed the presence of corrosion changes that should not occur under normal operating conditions. The results of the research work indicate that tire rupture was caused by delamination of the material coatings and corrosion of the steel cord wires. These defects could have arisen due to the earlier cracking of the rubber layer and the ingress of moisture or as a result of the use of corroded steel cord wires in tire production. In the analyzed case, the driver could not regain control of the vehicle and avoid a collision with oncoming vehicles. [ABSTRACT FROM AUTHOR]

Metal-elastomer bonded joints are typical of different industrial applications, specifically pallet truck wheels, where the solid elastomeric layer is bonded to the metal body. This paper focuses on the effect of manufacturing parameters and working temperature, on the shear strength of a metal-elastomer bonded joint. Through a comprehensive experimental test plan, the paper investigates the effect of thermal conditioning of the adhesive, shot peening of the metal adherend, type of solvent-based adhesive, and working temperature of the joint. The test plan uses a TAST-like specimen with a sandwich configuration (metal-elastomer-metal), loaded in order to originate a nearly pure-shear stress state. The results show which parameters influence most the shear strength of the joint helping the designer in maximizing the load-carrying capacity of the joint. [ABSTRACT FROM AUTHOR]

Truck-lifting accidents are common in container-lifting operations. Previously, the operation sites are needed to arrange workers for observation and guidance. However, with the development of automated equipment in container terminals, an automated accident detection method is required to replace manual workers. Considering the development of vision detection and tracking algorithms, this study designed a vision-based truck-lifting prevention system. This system uses a camera to detect and track the movement of the truck wheel hub during the operation to determine whether the truck chassis is being lifted. The hardware device of this system is easy to install and has good versatility for most container-lifting equipment. The accident detection algorithm combines convolutional neural network detection, traditional image processing, and a multitarget tracking algorithm to calculate the displacement and posture information of the truck during the operation. The experiments show that the measurement accuracy of this system reaches 52 mm, and it can effectively distinguish the trajectories of different wheel hubs, meeting the requirements for detecting lifting accidents. [ABSTRACT FROM AUTHOR]

Railway track maintenance services aim to shorten the time of removing failures on the railways. One of the most important element that shorten the repair time is the quick access to the failure site with an appropriate equipment. The use of road-rail vehicles is becoming increasingly important in this field. In this type of constructions, it is possible to use proven road vehicles such as self-propelled machines or trucks running on wheels with tires. Equipping these vehicles with a parallel rail drive system allows for quick access to the failure site using both roads and railways. Steel rail wheels of road-rail vehicles are designed for specific applications. Since the total weight of vehicle is a crucial parameter for roadworthiness, the effort is made to minimize the mass of rail wheels. The wheel under consideration is mounted directly on the hydraulic motor. This method of assembly is structurally convenient, as no shafts or intermediate couplings are required. On the other hand, it results in strict requirements for the wheel geometry and can cause significant stress concentration. Therefore, the problem of wheel geometry optimization is discussed. Consideration is given to the use of ER8 steel for railway application and 42CrMo4 high-strength steel. Finite element analysis within Ansys software and various optimization tools and methods, such as random tool, subproblem approximation method and first-order method are applied. The obtained results allow to minimize the rail wheel mass with respect to the used material. Moreover, computational demands and methods leading to the best results are compared. [ABSTRACT FROM AUTHOR]

In Nigeria, goods haulage is currently dominated through heavy trucks, whose effect on the pavement deterioration can be enormous, because the truck wheel/pavement interaction plays a key role in deterioration of pavement life. This study aims to measure the truck wheel/pavement contact characteristics with a view to develop its quantitative damaging influence on a pavement structure. Axle load distribution, tyre inflation pressure and tyre/pavement contact area of selected tyre types for different axle configurations were determined for four classes of trucks being used by a major haulage outfit in Nigeria, Messrs Dangote Industries Limited. The results obtained showed that the tyre pavement contact length depends on tyre load as the length increases with increase in tyre load, while tyre pavement contact width is averagely constant with tyre load increase. It is concluded that design and use of tyres should allow for large contact areas with small tyre pressures to lessen the menace of pavement deterioration, and also there is need for a strict control for standards of truck loads that travel on Nigerian road. [ABSTRACT FROM AUTHOR]

The objective of this paper is to validate the integrated kurtosis-based algorithm for Z-notch filter (I-kaz) Vibro method for monitoring hand arm vibration (HAV) in three-tonne truck steering wheels using independent component analysis (ICA). From the recorded HAV signals for acceleration (Acc), velocity (Vel) and displacement (Dis), ICA is used to obtain the independent components, IC1 and IC2. Comparison between the I-kaz display and I-kaz Vibro coefficient (Zv 8) with the proposed ICA display and independent component kurtosis coefficient (KIC) shows that HAV acceleration (a), Zv 8 and KIC values increase when vehicle speed is increased. In addition, these results are also supported by the observation of the scattering of the I-kaz Vibro and ICA displays, whereby larger space of scattering is found for increasing vehicle speed, indicating that Zv 8and KIC values are comparatively increasing. Comparison of the fast Fourier transform (FFT) plots of the original HAV acceleration signal with the two independent components shows that the vibration value for each frequency in the FFT graph did not change between the recorded HAV data with each of the two independent components, and the relative error between the maximum level is considered to be within practically acceptable relative error limits. Thus, it can be concluded that the I-kaz Vibro method for HAV monitoring has been validated accurately using ICA. [ABSTRACT FROM AUTHOR]

With respect to heavy carrying tasks and uneven road surface in open pit mine, the mechanical performances of electric wheel dump truck frame regarded as the main bearing component are extremely important for its safe operation. For the problem of insufficient strength and stiffness, an interval multi-objectives optimization design method based on blind number theory is presented in this paper, taking into account uncertain factors caused by manufacturing process. The allowable interval strength of welding material and permissible interval bending and torsional stiffness are obtained by means of experiments and simulations, using the blind number theory. Based on Latin hypercube sampling technique, the strength and stiffness of frame under different conditions is estimated. It shows that in the case of braking interference between interval strength and interval dynamic stress appears. Strength and stiffness are considered as optimization objectives, while the thicknesses of top longitudinal beam, stiffener, lateral longitudinal beam and hanging ear in the frame are deeded as design variables, and Young's modulus and Poisson's ratio are taken as uncertain variables. The optimized results show that the stress and deformation of the frame due to dynamic loading decreased. This result enables to formulate the following sentence: the mechanical performance of frame is improved. [ABSTRACT FROM AUTHOR]

Bridge weigh-in-motion (BWIM) technology, which identifies traffic information such as the axle weights, wheelbases, and velocities of vehicles passing over a bridge from bridge responses, can be beneficial for bridge design, management, and maintenance. However, conventional BWIM methods simplified the coaxial wheel loads of a vehicle using one concentrated force, commonly known as the axle load. Such simplification would lead to two problems. Firstly, it fails to calculate the wheel weights of moving vehicles, which are essential for evaluating the service status of roads and is required to be measured by national weigh-in-motion specifications, such as ASTM E1318-09. Secondly, the transverse distance between the coaxial wheels (track width), and unequal load distributions between left and right coaxial wheels (unbalance) were ignored in the conventional BWIM methods. However, these two factors represented the actual characteristics of the vehicle load applied on the bridge. Hence, ignoring these two factors could lead to significant errors in estimating the vehicle weight when the track width or the unbalance ratio of the test vehicle was different from that of the calibration vehicle. To address the above two problems, this study proposed a new BWIM method, where two concentrated loads with fixed transverse distance were used to represent the coaxial wheel loads of the truck in analyzing the interactions between the truck and the bridge. By doing so, the wheel weights of moving vehicles can be calculated, and both the effects of the unbalance and the track width can be considered in estimating the axle weights of the vehicle. Both experiment results and simulation results demonstrated that the proposed method can effectively identify the wheel weights of moving vehicles, and provide more accurate axle weights than conventional BWIM methods under complex traffic scenarios. [ABSTRACT FROM AUTHOR]

Copyright of Maintenance & Reliability / Eksploatacja i Niezawodność is the property of Polish Scientific & Technical Society Consumables, Polish Maintenance Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

90 accidents involving forklift trucks occur each year in Poland, resulting in nearly 100 injured persons including 10–15 fatalities. The most frequent and most dangerous accidents include those caused by the loss of stability of a forklift truck with the operator inside, resulting in its tip-over. More than a half of this type of incidents have a fatal outcome. The paper describes results of tests aimed at verifying the effectiveness of passive safety systems used to protect the operator against the effects of the truck tip-over. The tests were performed with the use of numerical simulation. The authors selected 12 configurations taking into account the forklift’s velocity, position of the steering wheel and seat and the operator’s reaction, in terms of which selected passive safety systems were tested. In order to conduct the effectiveness tests of these systems, a simulation model was developed, consisting of numerical models of: a forklift truck, human body, ground and tested passive safety systems. This was followed by a series of simulations of the forklift tip-over with the operator inside, with the use of different passive safety systems. More than 170 simulations of possible cases were performed in total. Results, in the form of recorded resultant acceleration of the head, were used to estimate the severity of injuries for each case considered. This was used as a basis to determine the effectiveness of the passive safety systems. [ABSTRACT FROM AUTHOR]

A company produces truck wheel covers as spare parts for the local market. The production of these parts is based on a progressive die performing consecutive forming and selective cutting stages throughout the initial circular steel sheet. The failure occurred to the final stage of manufacturing, as the die marks, by mold-printing, the assembly configuration of the wheel cover onto the wheel rim. The paper presents a thorough failure analysis of the broken tool. The investigation includes preliminary examination, hardness measurements and chemical analysis. In depth microscopic examination was carried out using stereoscope and optical and electron microscopy. The failure mechanism was investigated from macroscopic and microscopic perspective and conclusions regarding the crack initiation and propagation were conducted and analyzed. The causes that led to the total fracture were discussed. The design of the tool and improper surface roughness are considered to be the main causes of the failure. Some complementary recommendations were proposed so to enhance the production rate of the specific tool. [ABSTRACT FROM AUTHOR]

A wheel force transducer is a vital instrument in the vehicle-testing field which provides a means for determining experimentally the forces and the moments transmitted to a vehicle through the tyre contact patch. However, existing wheel force transducers are almost commercial products. They are expensive and, for business reasons, technical information is not made public. This slows down the development of the wheel force transducer itself to a certain extent. Moreover, research studies on the wheel force transducer mainly focus on utilization of this tool for vehicle simulations, traction control and anti-lock braking evaluation as it provides information on the characteristics, the performance and the limitations of the vehicle. From the perspective of the sensor itself, although improvement in the transducer accuracy and information extraction using signal-processing methods have been successfully developed in the literature, few investigations on the design of the wheel force transducer have been reported yet. Accordingly, a general design and optimization procedure for the wheel force transducer with a practical case study will be of great significance. Since technical difficulties, admittedly, are primarily about the issues of how to design and optimize the transducer, in this paper a new self-decoupled six-axis wheel force transducer for a heavy truck is designed and fabricated. An easy-to-understand design procedure is highlighted mainly including the conceptual design with the aims of a universal-purpose self-decoupled transducer with an eight-spoke structure, an optimization design which depends on the proposed comprehensive performance criteria in the computer-aided procedure, and a collectivity design focus on the mechatronics assembly for a heavy-truck application. Finally, the wheel force transducer is manufactured, calibrated and tested. The results show that the mean errors of the six-axis forces are about 3% of the full scale with 1% non-linearity, 0.5% repeatability and 1% hysteresis for the sensor only, that there are increased mean values of about 2% non-linearity, 1% repeatability and 1.4% for a certain tyre assembly and that the observed dynamic response is about 2.5–3.5 ms. Both the self-decoupled characteristics and the sensor performance are verified to meet the design and optimization, and the transducer with a real-time wheel force output is also confirmed by road tests. [ABSTRACT FROM AUTHOR]

This paper focuses on the behavior of skewed concrete bridge decks on steel superstructure subjected to truck wheel loads. It was initiated to meet the need for investigating the role of truck loads in observed skewed deck cracking, which may interest bridge owners and engineers. Finite-element analysis was performed for typical skewed concrete decks, verified using in situ deck strain measurement during load testing of a bridge skewed at 49.1°. The analysis results show that service truck loads induce low strains/stresses in the decks, unlikely to initiate concrete cracking alone. Nevertheless, repeated truck wheel load application may cause cracks to become wider, longer, and more visible. The local effect of wheel load significantly contributes to the total strain/stress response, and the global effect may be negligible or significant, depending on the location. The current design approach estimates the local effect but ignores the global effect. It therefore does not model the situation satisfactorily. In addition, total strain/stress effects due to truck load increase slightly because of skew angle. [ABSTRACT FROM AUTHOR]

The solid wheels often found on industrial trucks maybe subject to failure of the wheels' rubber coating under certain load conditions. To date, there has been no adequate analytical model to predict these conditions and the design of these wheels has been based on costly trial and error. In this work, an elastostatic analytical model is developed, which describes the interaction of the wheel with the rigid ground in terms of relative approach, contact width, and contact pressure for a given load applied to the wheel. This model has been validated by comparison with both experimental measurements and finite-element analyses, showing strong agreement for all three parameters. The results of the proposed model are more accurate than those of previous analytical models reported in the literature for rubber-coated rotary equipment. The new model can be used to design against creep or excessive deformation of the wheel coating. [ABSTRACT FROM AUTHOR]

• A hydraulic hub-motor auxiliary system (HHMAS) is used in the traditional trucks. • Based on the HHMAS, a coordinated control algorithm is designed. • The designed pump displacement control method is real-time in real vehicle test. • HHMAS has a good effect on the control strategy presented in this paper. To solve the contradiction between the trafficability and the power of traditional heavy trucks, the study proposes a coordinated control of hydraulic hub-motor auxiliary system for heavy truck to make full use of the coefficient of ground aadhesion and engine power. With hydraulic hub-motor auxiliary system (HHMAS) in the non-drive front wheels, the front wheels drive the truck on bad roads to ensure the trucks tractive capacity and exit on good roads to achieve better transmission efficiency. Based on the HHMAS, a wheel speed coordinated control strategy that considers slip efficiency to make system work effectively is designed. The pump displacement composite control method in the real vehicle is tested, the steady-state error is basically within 0.03. Experimental results show that HHMAS has a good effect on the control strategy presented. Hence, the study on HHMAS is a valuable to hydraulic hybrid application. [ABSTRACT FROM AUTHOR]

The aim of this study is to design and test a new, simple, and reusable linear variable differential transformer (LVDT)-based in situ bolt preload monitoring system (L-PMS) during fastening of a truck wheel assembly. Instead of measuring the elongation of a bolt, the distance between the end surfaces of both the bolt and nut was monitored via the L-PMS. The distance obtained from the L-PMS was experimentally correlated with the actual preload measured by a washer-type load cell. Since the variation of the distance is related to the stiffness of the bolt and clamped parts, a finite element analysis was also conducted to predict the sensitivity of L-PMS. There was a strong linear relationship between the distance and bolt preload after the bolt and nut were fully snugged. However, a logarithm-shaped nonlinear relationship was irregularly observed before getting snugged, making it difficult to define a clear relationship. In order to tackle this issue, an arc-shaped conductive line was screen-printed onto the surface of the clamped parts using a conductive carbon paste. The results show that a resistance variation of the conductive line during fastening enables to determine the snug point, so the L-PMS combined with resistance measurement results in an approximately ±6% error in the measurement of bolt preload. The proposed L-PMS offers a simple but highly reliable way for measuring bolt preload during fastening, which could be utilized in a heavy-truck production line. [ABSTRACT FROM AUTHOR]

This paper presents a wheel cylinder pressure control algorithm for application to the vehicle electronic stability control (ESC) systems for commercial trucks. An ESC system is an active system that improves the driving stability by distributing the appropriate braking pressure to each wheel, which is an essential system for safe driving. It is important that the ESC system, through proper braking pressure supply, delivers the correct pressure under control. However, to reduce the cost involved, commercial trucks use a solenoid valve of the on/off-type, rather than a proportional valve that has good pressure control capability. The performance of a proposed wheel pressure control system based on an on/off solenoid valve control was verified by means of experiments conducted using the wheel pressure control algorithm presented in this paper. [ABSTRACT FROM AUTHOR]