Three-axle Truck Research Articles

Study of instability mechanisms of trucks turning right at long downhill T-junctions based on Trucksim simulation.

The aim of this study was to investigate the influence of road factors on the safety speed threshold of a lorry turning right around a corner at a the bottom of a long downhill T-junction. Trucksim simulation software was chosen to construct a model for investigating the turning instability mechanism. A three-axle truck was chosen as the simulation vehicle and road adhesion coefficients of 0.2-0.75, road super-elevations of -2-8%, turning radii of 20-100 m, and vehicle overcharge of 0-100% selected for tuning. Simulation experiments were carried out for different bending conditions, investigating the effects of each influencing factor on the destabilization speed threshold using the control variable method. The vehicle's lateral load transfer rate and lateral acceleration were indicators for determining whether a truck was unstable. The results showed that: a) the turning radius had the most significant influence on the speed threshold for cornering instability; b) the road surface adhesion coefficient and vehicle overweight had secondary effects; and c) the road height had a general influence.

Extension of AASHTO Load-Spreading Method to Include the Full Benefits of Pavements for Reliable Load Rating of Buried Culverts

This paper develops a two-step procedure to extend the AASHTO Ad Hoc Method (AAM) for live-load spreading through soil to include the full benefits of pavement overlays. The two-step procedure is called AAMP-θ* (“P” for pavements), which combines the Fox two-layer elasticity solution for peak stress at the pavement–soil interface with the improved AAM-θ* theory for load spreading through soil. The AAMP-θ* procedure is applicable to all culvert analysis tools commonly used for Load and Resistance Factor Rating (LRFR) analysis ranging from simple frame models to sophisticated two-dimensional finite element model (2D-FEM) soil structure models. The AAMP-θ* procedure is rigorously and completely developed wherein all approximations are shown to be conservative so that the predicted benefits of pavements are trustworthy and not overstated. This is why the more accurate AAM-θ* load-spreading method is used instead of the simpler but unconservative AAM-30° method. Application of AAMP-θ* for LRFR load rating of buried culverts is described for simple frame models as well as 2D-FEM pavement–soil structure models. Lastly, the AAMP-θ* procedure is validated by comparing structural response predictions from 2D-FEM solutions with strain-gage measurements in a buried corrugated steel culvert loaded by a three-axle truck. One set of strain-gage measurements was made before, and another set of measurements was made after, asphalt pavement was installed. The correlation between field data and 2D-FEM/AAMP-θ* predictions is remarkable and underscores the bottom-line message that AAMP-θ* should be used when performing LRFR analysis on buried culverts to determine realistic rating factor values and avoid predicting false unsafe values.

Evaluation of Failure Probability in Series System of Three-Axle Trucks under Strong Crosswind

The probability of wind-induced failure accidents in three-axle trucks under pulsating strong crosswinds and the corresponding critical safe speed are investigated in this study. Reliability theory and random fuzzy methods are utilized to establish the membership function of the failure probability in the series system (FPSS) composed of rollover, side-slip, and rotation failure accidents. The Kaman spectrum is used to realistically simulate the fluctuating wind time history curves of different average speeds. Four factors affecting the six-component force coefficient of the three-axle truck and the crosswind load are considered: fluctuating average wind speed, wind direction (angle), truck driving speed, and road adhesion coefficient. A three-axle truck nonlinear model is established accordingly. The model is used to obtain the dynamic response of the three-axle truck under strong crosswind conditions as per the time-varying curves of the vertical load of the truck, the time-varying curves of the lateral displacement of the center of mass, and the time-varying curves of the heading angle. An advanced Monte Carlo simulation algorithm based on importance sampling is used to determine the probability of a three-axle truck with FPSS under strong crosswinds; the given acceptable probability of failure (accident) is used to obtain the critical safety speed. The sensitivity analysis of random variables reveals that the possibility of three truck failures of the three-axle truck in strong crosswinds is, from largest to smallest, rollover, side-slip, and rotation. This research may provide useful guidance for exploring the probability of wind-induced accidents and the critical safety speeds of vehicles, as well as useful general information for road transportation management departments.

THE TRUCK TRAILER SUSPENSION AXLES FAILURE ANALYSIS AND MODELLING

The purpose of trucks is very diverse, but the main purpose is freight transportation. When cargos are transported, the truck’s suspensions are heavily loaded, so failures also occur most often in the suspension elements. For axles of trailers – tubular construction failures occur, they crack. Axle failure investigations are required to determine the cause of the failure. The paper analyses three-axle truck trailer suspension. Axle failure analysis and axial deformation modelling were performed to determine trends and causes of truck trailer suspension axle failures. Different cases with axles of tubular construction with wall thicknesses of 9 and 11 mm were modelled. The paper presented visual failure analysis of truck trailers suspension axles and finite element modelling results of axle’s deformation of different geometrical parameters. The results were discussed and conclusions were drawn.

Analysis and Optimisation of Ride Vibration of a Heavy-Duty Truck Based on a Vertical-Pitch-Roll Driver-Vehicle Coupled Dynamic Model

The ride comfort and the cargo safety are of great importance in the vibration design of heavy-duty vehicle. Traditional ride comfort design method based on the response of components of vehicles or interaction between human and seat overlooks the most direct criterion, the response of occupants, which makes the optimisation not targeted enough. It will be better to conduct the ride comfort design with the biodynamic response of driver. To this end, a 17-degrees-of-freedom (DOFs) vertical-pitch-roll vehicle dynamic model of a three-axle heavy-duty truck coupled with a 7 DOFs human model is developed. The ride comfort of human body under the vertical, the pitch, and the roll vibrations can be evaluated with the weighted root-mean-square (r.m.s.) acceleration of the driver in multiple directions. The flexibilities of chassis and carriage are also considered to improve the accuracy of the prediction of the ride comfort and to constrain the mounting optimisation of cab and carriage. After validation, the sensitivity analysis of the mounting system, the suspensions, and arrangement of sprung masses is carried out and significant factors to ride vibration are identified. The optimal combination of design parameters is obtained with the objective of minimizing the vibration of the driver and carriage simultaneously. The optimisation result shows that the weighted driver vibration is reduced by 27.9% and the carriage vibration is reduced by 31.8% at various speeds.

Approbation of an effective method for dynamic calculation of the steel and concrete bridge span

Problem statement. The article describes the method and results of determining the dynamic response of a continuous steel-reinforced concrete span of a road bridge to the passage of heavy vehicles, which is focused on the use of finite element computing systems. The data of dynamic calculations are compared with those obtained during full-scale dynamic tests of the operated structure. Results. Modern algorithms for dynamic calculation of continuous bridge structures on the action of sprung vehicles are analyzed, which allow taking into account the irregularities on the roadway, the influence of wheel bearing point movements on the vibrations of moving vehicles. It describes the sequence of performing dynamic calculations using modal analysis blocks and dynamic calculation of KE-complexes for a system of moving non-inert loads, followed by calculating the dynamic component of deflections and forces of elements of the bridge structure, taking into account the inertia of the vehicle and unevenness on the roadway. According modal analysis of steel-concrete span structures road bridge operated by means of spatial finite element calculation schemes are determined by their own shape supporting structure, which are then used for dynamic calculations in a moving inertial load. The results of dynamic calculations of the operated road bridge on the action of a three-axle truck moving at a constant speed are presented. Calculated deflections are compared with those obtained during full-scale static tests of the bridge. Numerical calculations estimate the effect of speed, roadway irregularities, and feedback between the vibrations of the bridge and the moving vehicle. Conclusion. The proposed method of dynamic calculation of bridge structures allows evaluating the dynamic quality of transport structures at the design stage and making optimal design decisions.

Research on loaded brake performance test of trucks

In this paper, the axle load model of three-axle truck upon lift loading is built, and the calculation model of vehicle centroid position is created as well. The effectiveness of the axle load model is verified by real vehicle test with a three-axle heavy duty van. The maximum relative error between model calculation results and real test values is 3.17%, which indicates that the axle load model is valid. Based on the axle load model, analysis is conducted to get impact laws of lifted height, wheelbase, centroid position and composite stiffness on the lift loaded axle load, which provides a basis for the vehicle braking performance test. According to the results of real vehicle tests, the maximum braking force of the first, second and third axles is increased by 30.6%, 73.3% and 5% after respective axle is lift loaded.

Vibrations of continuous slab reinforced concrete bridge when driving a three-axle car

Problem statement. The technique and its approbation on the reconstructed transport construction of full-scale dynamic tests of the continuous slab span of the road bridge using a refined algorithm of dynamic calculation of the mobile inert load are presented. Results. The modern methods and algorithms of calculation of transport facilities for mobile road load, which can be used in the design and full-scale dynamic tests of road bridges, are analyzed. Affected by many factors, including design features bearing system of the bridge and the moving crew, the presence of unevenness on the carriageway etc., which need to be considered in the evaluation of the dynamic characteristics of transport facilities. Describes the methodology and processing of data from the field dynamic testing of a road bridge, which studied dynamic response of a slab of reinforced concrete spans for the passage of a three-axle truck through the artificial a single bump. The spectral analysis of the registered vibration patterns is performed, the results of which are compared with the eigen frequency spectrum of the superstructure. The calculated analysis of the situation of the vehicle passage on the roadway of the bridge with the allocation of quasi-static and dynamic components of the oscillations is carried out. The latter is used for the lower self-forms a bridge, which defines the dynamic quality transport facilities. Conclusion. The performed approbation of the proposed technique can be effectively used both in the dynamic tests of constructed or operated bridges, and in the design of new transport facilities.

Application of Udwadia–Kalaba approach to semi-active suspension control of a heavy-duty truck

As an important component of the chassis system, the vehicle suspension plays a significant role in vehicle comfort, stability, and safety. In dynamic modeling of a semi-active suspension, traditional method is a complicated process, the actuator force is difficult to solve. In the process of model simplification, the influence of the vehicle-axle and balanced shift quality on the vehicle dynamics is not considered. For this reason, applying the Udwadia–Kalaba approach to dynamic modeling and control for a three-axle semi-active truck suspension can establish a simple and accurate equivalent discrete system. By fixing the displacement and acceleration of the body, the simulation is conducted with real excitations between the road and six wheels, and the actuator control forces of the semi-active suspension are obtained under the constraint by applying the Udwadia–Kalaba approach. The contrast in the analysis results from the Udwadia–Kalaba approach and the traditional Lagrange multiplier method indicate that the Udwadia–Kalaba equation can obtain the semi-active suspension actuator forces without introducing additional Lagrange multipliers and that the actuator forces acquired with the Udwadia–Kalaba approach are equal to those of the traditional Lagrange multiplier method.

Research on loaded brake performance test of trucks

In this paper, the axle load model of three-axle truck upon lift loading is built, and the calculation model of vehicle centroid position is created as well. The effectiveness of the axle load model is verified by real vehicle test with a three-axle heavy duty van. The maximum relative error between model calculation results and real test values is 3.17%, which indicates that the axle load model is valid. Based on the axle load model, analysis is conducted to get impact laws of lifted height, wheelbase, centroid position and composite stiffness on the lift loaded axle load, which provides a basis for the vehicle braking performance test. According to the results of real vehicle tests, the maximum braking force of the first, second and third axles is increased by 30.6%, 73.3% and 5% after respective axle is lift loaded.

A crane-manipulator transfer position impact on a chassis loadings of a base vehicle

In the article it was analyzed the influence of the configuration of the crane in transport mode on the loading of the suspension base chassis (truck). To do this a mathematical model was developed to represent motion equations of the system of lumped masses connected by elastic-dissipative ties. Integration of the motion equations takes into account the influence of the surface roughness of the support base and the load moment of the crane-manipulator. Deformation and efforts in the suspension are evaluated based on the static and dynamic components, calculated using the developed model. Calculations are made for a three-axle truck KAMAZ 53215, equipped with a Kanglim KS3105 crane. The results of computer simulation using mathematical models have shown that the location of the crane boom forward leads to a significant overload of the front suspension of the base chassis. The location of the crane boom backwards leads to unloading the front suspension of the base chassis. However, overloading of the rear suspension is much lower, as the rear suspension of the vehicle are mostly oriented on the perception of the weight of the payload. When moving the base truck with the transport position of the crane boom forward dynamic component of the load on the front suspension is higher by 10...15% higher than in the transport position of the crane boom backwards, and the load on the rear base of the chassis is lower by 8...9 %. The developed mathematical model and calculation methodology should be used for the rational choice of the transport configuration of the crane with specific given characteristics of the basic truck and cargo load.

Modeling a Three-axle Truck and Vibration Analysis under Sinusoidal Road Surface Excitation

Modeling a Three-axle Truck and Vibration Analysis under Sinusoidal Road Surface Excitation

Vibration of vehicle-bridge coupling system with measured correlated road surface roughness

The present study investigated the effect of the correlation of the measured road roughness profiles corresponding to the left and right wheels of a vehicle on the vibration of a vehicle-bridge coupling system. Four sets of road roughness profiles were measured by a laser road-testing vehicle. A correlation analysis was carried out on the four roughness samples, and two samples with the strongest correlation and weakest correlation were selected for the power spectral density, autocorrelation and cross-correlation analyses. The scenario of a three-axle truck moving across a rigid-frame arch bridge was used as an example. The two selected road roughness profiles were used as inputs to the vehicle-bridge coupling system. Three different input modes were adopted in the numerical analysis: (1) using the measured road roughness profile of the left wheel for the input of both wheels in the numerical simulation; (2) using the measured road roughness profile of the right wheel for both wheels; and (3) using the measured road roughness profiles corresponding to left and right wheels for the input corresponding to the vehicle's left and right wheels, respectively. The influence of the three input modes on the vibration of the vehicle-bridge system was analyzed and compared in detail. The results show that the correlation of the road roughness profiles corresponding to left and right wheels and the selected roughness input mode both have a significant influence on the vibration of the vehicle-bridge coupling system.

ANSYS-Based Spatial Coupled Vibration Analysis Method of Vehicle-Bridge Interaction System

An ANSYS-based spatial approach of analysis is proposed for the bridge-vehicle interaction to investigate the dynamic responses of a curved concrete box girder bridge and vehicles. The governing equations of a vehicle model with twelve-degrees-of-freedom (12DOF) are derived from the energy method using the Lagrange equation of motion. Both the bridge and the vehicle system are discretized adopting element type BEAM44, MASS21 and COMBIN14 in the ANSYS program. The interaction forces between the vehicle and bridge are deduced considering the road surface roughness and its velocity term based on the compatibility conditions of the contact points, and detailed formula are presented. The separate iterative algorithm is developed to solve the vehicle-bridge interaction problem. A three-axle cargo truck and a dual-cell box girder curved overpass bridge are chosen for both numerical and field test analysis. The dynamic properties and the dynamic responses of the bridge are both obtained from the numerical and experiment way, and the results agree well with each other by comparison. Its indicated that the procedures presented in this paper can be taken for the further vibration analysis study of curved concrete box girder bridges.

Analysis on Vehicle-Bridge Coupled Vibration of a Rigid-Frame Arch Bridge Based on Measured Road Roughness

Firstly, synchronous field measurements were carried out for the road roughness of the left and right wheels to obtain the roughness profile using a high speed laser roadway testing vehicle. Secondly, programming idea of multi-girder vehicle-bridge coupled vibration analysis module was presented briefly. Finally, a three-axle heavy truck crossing a rigid-frame arch bridge was taken as an example, detailed comparing and analyzing was carried out for the influence on the dynamic responses and spectrum characteristics of the vehicle-bridge system from three excitation cases which include using measured road roughness corresponding respectively to left and right wheels, using measured road roughness of left wheels and right wheels simultaneously. The analysis shows that when the differences in road roughness between left and right wheels are significant, the responses computed with inconsistent excitation is smaller than that with both of the latter two excitation cases, and there are some differences between the vertical contact forces of wheels and the spectrum characteristics of the vehicle-bridge system.

Analytical and Experimental Approach for Assessing Vibration Serviceability of Highway Bridges Due to Heavy Vehicle Traffic

The major goals of this paper are to evaluate the serviceability of bridges with vibration problems among these structures in actual use, and to establish the evaluation criteria based on the evaluation results. To accomplish these goals, the vehicle’s weight, moving velocity, displacement from the measurement position, and acceleration were measured through the field test to evaluate the bridge’s serviceability with respect to its vibration characteristics. Furthermore, the vibration characteristics of the bridge were analyzed with respect to various factors that influence its vibration. For this purpose, the three-axle truck used in the field test was modelled as the moving vehicle with 8 degrees of freedom, and the bridge considered was modelled using the frame element. According to the comparison of the analytical and experimental results, the analytical method that was used to evaluate the bridge’s vibration serviceability as suggested in this paper based on the results of the analysis and field test is feasible.

Effect of obstacles on roads with different waviness values on the vehicle response

The effect of the increasing number of cosine-form obstacles, which are superposed on a standard homogeneous longitudinal road profile, is studied when the waviness of the basic road profile changes in the range from 1.5 to 3.5. First, the effect of the composed profile on the power spectral density (PSD) is analysed. It appears that the primary PSD in the form of a straight-line in the log–log plot breaks into two straight-line partial segments with quite different waviness values in the long and short wavelength bands. This seems to be a suitable model of a highly deteriorated road. Next, the effect on the response of two typical vehicles, viz. a personal car and a three-axle truck, is studied, and rather different results were obtained. In a summary valuation, it appears that the presence of additional obstacles causes independence of some of the vehicle response quantities of the primary waviness.

Effect of obstacles in the road profile on the dynamic response of a vehicle

The simulation study is aimed at explaining the effect of large obstacles (bumps and potholes) appearing on a road surface on the response of a vehicle passing the obstacle. For the tyre representation, the simplest point-follower model was used. Only the random obstacle modelled by cosine waves of variable height and constant height-to-length ratio was applied. For the traversing vehicle, two models were considered: a planar model of a personal car with a driver and one passenger, and a planar model of a three-axle truck. Vertical accelerations acting on the travelling people and dynamic tyre forces were estimated. In the first part of this paper, the dependences of the extreme values of the vehicle responses when passing an isolated obstacle on the obstacle height and the travel speed were evaluated. In the second part of this paper, the r.m.s. values of the same quantities were evaluated when the vehicle passes a road section with a standard pure random profile on which a number of randomly distributed obstacles were superimposed. The dependences of all quantities in question on the ‘obstacle density’ and on the travel speed were estimated.

Calculating an influence line from direct measurements

The response of a bridge to a pre-weighed truck can be measured on site. This paper describes a mathematical method for converting the measured response of a load effect into an influence line for that effect. One influence ordinate is calculated for each scan of the data acquisition system. The vector of ordinates is found by solving a large set of simultaneous equations expressed in matrix form. The general form of the matrices is described, and the particular matrices for a three-axle truck are given. The technique is demonstrated using measured strain on two bridges using pre-weighed trucks with different numbers of axles.

Minimizing Distress on Flexible Pavements Using Variable Tire Pressure

The potential of variable tire pressure technology to minimize distress on flexible pavements with thin asphalt surfacing layers and peat soil subgrade was evaluated using in-situ stress-strain data. Pavement interfacial strains and corresponding subgrade stresses imposed by a three-axle truck were measured and used to estimate the fatigue life of the surfacing layer. Three levels of truck wheel loads in combination with four tire inflation pressures (350, 490, 630, and 770 kPa) were used to evaluate the potential distress by the single steering wheel and rear dual wheels in tandem. Results suggest that lateral strain due to the single steering wheel is the most critical to fatigue failure, which is influenced by the viscoelastic nature of asphalt, and therefore truck speed and axle configuration are important. Lower tire pressures increased the fatigue life of the surfacing layer with respect to the rear dual wheels and the steering wheel by up to 200 and 300%, respectively. Haulage trucks with systems for managing variable tire pressure such as the central tire inflation systems may therefore enhance the serviceability of pavements overlying peat or other soft soil foundations.