Vehicle Dynamic Load Research Articles

Pavement Primary Response Using Influence Function and Peak Influence Function

It was identified in previous research that errors in theoretical damage much associated with the influence function calculation. Thus, this paper present the efficient prediction of primary response due to dynamic vehicle loading using influence function and peak influence function approach. In order to provide the realistic loading condition, dynamic road response model with idealised loads representative by mathematical quarter-truck model with two degree of freedom was excited by a random road surface profile which equally spaced points along the simulated road with various different speeds. Consequently, the simplified computational approach (peak influence function method) was identified only a few points gave a small different compare with the influence function method for along the longitudinal distance. In order to identify the impact of both methods, further implementation was done to calculate fatigue damage (horizontal tensile strain at the bottom of a bound layer) or rutting damage (vertical compressive strain at the top of the subgrade layer) predicted by constant load moving at varies speed. It was found that the differences in response are particularly small and increased steadily as the increasing of the vehicle speed. It was conclude that the simplify calculation was able to predict stresses and strains sufficiently accurately and identified relatively small errors into the pavement damage prediction. Hence the simplification in particular much reduced the computation time sufficiently and minimized the computer resources significantly.

Study on the Influence of Beam Rigidity on Continuous Rigid Frame Bridge with Moving Vehicle

The continuous rigid frame bridge has been applied widely in our country. But in recent years, over-deflection of beam in this bridge has become an serious problem. This may cause the redistribution of displacement and internal force of the whole structure, especially in dynamic load status. A two-dimensional pile-soil-bridge model is built up in ANSYS based on a factual bridge. The over-deflection is considered as the decrease of beam elastic modulus or rigidity. The displacement and internal force of key parts are analysed in static and dynamic vehicle load. The study shows that over-deflection will reduce the first three natural vibration frequency, weaken the sensitivity of bridge to dynamic load. In dynamic load status, the displacement and internal force will be influenced by beam rigidity.

Study on the Influence of Beam Rigidity on Continuous Rigid Frame Bridge with Moving Vehicle

The continuous rigid frame bridge has been applied widely in our country. But in recent years, over-deflection of beam in this bridge has become an serious problem. This may cause the redistribution of displacement and internal force of the whole structure, especially in dynamic load status. A two-dimensional pile-soil-bridge model is built up in ANSYS based on a factual bridge. The over-deflection is considered as the decrease of beam elastic modulus or rigidity. The displacement and internal force of key parts are analysed in static and dynamic vehicle load. The study shows that over-deflection will reduce the first three natural vibration frequency, weaken the sensitivity of bridge to dynamic load. In dynamic load status, the displacement and internal force will be influenced by beam rigidity.

Analysis of Dynamic Load Level of High-Speed Heavy Vehicle Imposed on Uneven Pavement

Based on the significant destructive effect of heavy vehicle on uneven roads, two simplified models of pavement unevenness and vehicle dynamic load were established in accordance with D'A lembert principle, and Matlab software was used to analyze the changing law of dynamic load under the conditions of different road unevenness, vehicle speed and load. The results show that vehicles running on uneven road may produce more cumulative damages than static load, and DLC (dynamic load coefficient) changes in wide range, maximum up to 2.0 or more; the effect of speed and load on dynamic load is complex, and due to multi-factor interaction, DLC doesn’t consistently increase or decrease with speed and load increasing. Although the dynamic load level caused by high-speed heavy vehicle is not necessarily too high, its impact on the road can not be ignored.

유도전동기를 이용한 차량주행특성 시뮬레이터

In this paper, we propose vehicle running characteristic simulator. The developed simulator is configured by two induction motors which are directly coupled with each other. One motor is to simulate the vehicle drive and another motor is to simulate the vehicle dynamic load including running resistance, gradient resistance and adhesive characteristics between rail and wheel. The running characteristics of vehicle are modeled by numerical formulas. These are programed by software of embedded controller. Thus, it is possible to change several running characteristics during the running test freely and instantly. To evaluate the feasibility of the simulator, the experiments on slip and adhesion coefficient are performed. Additionally the adhesion control and speed control of vehicle are tested with simulator. Experimental results show that the simulator can produce the driving characteristics similar to the vehicle system.

Remaining Life Prediction of Asphalt Pavement under Dynamic Load

AbstractTaken pavement surface roughness as excitation, a 1/2 vehicle vibration model with 4 degrees of freedom was built, and the dynamic vehicle load was analyzed by the system dynamics and the vehicle vibration theory. In consideration of the factors of dynamic road and environment, the pavement evenness deterioration and permanent deformation were calculated according to amendment Shell permanent deformation theory. Then, a new remaining life prediction method of asphalt pavement was proposed in combination with the test results of expressway surface evenness and current quality standard. The results indicate that this method not only can accurately predict the remaining life of asphalt pavement but also can provide evidence for evaluating pavement service quality and scheming the best cost—effectiveness maintenance scheme of pavement.

The Vehicle Dynamic Load Indentification under the Excitation of Random Road Surface

In this paper, inverse pseudo excitation method for vehicle dynamic load identification is used. When the vehicle is in stationary random vibration, the vehicle dynamic load spectrum recognition problem is solved by using the deterministic method. The auto-PSD and cross-PSD of vehicle vibration response is known. Base on the reversing the power spectrum of road excitation, Vehicle dynamic load PSD is obtained. The results show that, Inverse pseudo excitation method for solving the vehicle dynamic load spectrum has good solution accuracy, put forward new ideas and methods for vehicle engineering practice, and has broad application prospects.

The effect of road unevenness on the dynamic vehicle response and ground-borne vibrations due to road traffic

In this paper, the relation between road unevenness, the dynamic vehicle response, and ground-borne vibrations is studied. In situ measurements of road unevenness and the dynamic vehicle response for six roads with different types of pavement are supplemented by numerical predictions of ground vibrations. The predictions are performed in two stages. In the first stage, the dynamic vehicle response is computed based on the measured road unevenness. The vehicle model is validated by comparing the predicted and measured vehicle response and subsequently used to predict the dynamic vehicle loads. In the second stage, the dynamic road–soil interaction problem is considered and the transfer functions between the road and the soil are computed. The effect of the pavement type (continuous, jointed, or composed of individual pavers) on the road–soil transfer functions is investigated and the free field vibrations are calculated using the dynamic vehicle loads computed in the first stage. The predicted free field vibrations are validated by measurements at one of the measurement sites before and after rehabilitation of a deteriorated concrete pavement. Finally, the results are used to investigate the relation between indicators of road unevenness such as the ISO 8608 road class, the International Roughness Index, and the coefficient of evenness on one hand, and the dynamic vehicle response and level of ground-borne vibration on the other hand.

Remaining Life Prediction of Asphalt Concrete Pavement under Dynamic Load

With the theory of M.W.Sayers, the pavement surface roughness was simulated by the sine curve. Through the Mat lab and VC + + program, the dynamic vehicle load caused by pavement surface roughness was analyzed and calculated. Given the dynamic road and environment factors and combined the test results of highway surface roughness, the deterioration law of pavement roughness were studied by amendment Shell permanent deformation theory. A new prediction method was put forward to predict the remaining life of asphalt concrete pavement, which was proved to be reasonable and reliable and can provide a valuable basis for the scientific decision-making of asphalt pavement management.

Response Analysis of Asphalt Pavement on Vehicle Dynamic Load Based on Numerical Method

The three dimensional finite element model of the pavement has been built on the basis of elastic-plastic finite element method and the assumption of the layered system of asphalt pavement. The layered flexible pavement is composed of asphalt surface, granular base and cohesive soil subgrade and is acted by dynamic movement load. The simulation results show that vertical displacement of asphalt surface has the maximum value and reduces gradually with the improvement of the road depth. Vertical stress, longitudinal stress and transverse stress result in the fatigue damage of asphalt pavement together. The key factor is the alternating variation of longitudinal stress. The maximum longitudinal stress and the maximum transverse stress exist in the junction of the asphalt layer and the granular base. Furthermore, the maximum longitudinal strain and the maximum transverse strain are induced in the junction of the granular base and the soil subgrade.

Study on the Dynamic Wheel Load of Multi-Axle Vehicle Based on Distribute Loading Weight

To study the dynamic wheel load on the road, a dynamic multi-axle vehicle mode has been developed, which is based on distribute loading weight and treats tire stiffness as the function of tire pressure and wheel load. Taking a tractor-semitrailer as representative, the influence factors and the influence law of the dynamic load were studied. It is found that the load coefficient increases with the increase of road roughness, vehicle speed and tire pressure, yet it decreases with the increase of axle load. Combining the influences of road roughness, vehicle speed, axle load and tire pressure, the dynamic load coefficient is 1.14 for the level A road, 1.19 for the level B road, 1.27 for the level C road, and 1.36 for the level D road.

Study on the Energy Conversion from the Dynamic Load of Vehicles on the Road Using Piezoelectric Materials

Many researchers have studied the harvesting from discarded energy such as solar energy, wind and vibration because of the exhaustion of fossil fuel and the environmental pollution. Particularly, vibration-based energy harvesting has increasingly received an attention in last decade. Therefore, the aim of study is to analyze the characteristics of piezoelectric materials to be used in the energy conversion system on vehicle road. At first, the dynamic loads of vehicle on the road are measured with respect to the weight and speed prior to analyzing the characteristics of piezoelectric materials. Then, the energy conversion amount of piezoelectric element is quantified for its size and type under the load profiles. The vehicle dynamic load is the average of 200kgf. The result indicates that the dynamic vehicle load is less affected by the speed. The generated voltage is 1.8kV, and extracted energy is 0.11mJ from one under the load of 8kgf applied on piezoelectric element. The power extracted from one passenger vehicle is able to operate a sensor and transmit acquisition data.

Development of a twin-accumulator hydro-pneumatic suspension

A twin-accumulator hydro-pneumatic suspension has been developed based on the off-road vehicle in order to meet the requirements of ride comfort. The working principle and elements construct of the developed suspension are studied. And then, a mathematical model of the developed suspension is built. The influence of twin-accumulator hydro-pneumatic suspension parameters on the vehicle body vertical acceleration, suspension travel and dynamic tyre load is studied by simulation based on a quarter off-road vehicle model. The ride comfort of the vehicle with the developed suspension is studied by a theoretical evaluation; also the ride comfort of the vehicle with twin-accumulator hydro-pneumatic suspension is compared with the one with single accumulator hydropneumatic suspension in both time domain and frequency domain. The result shows that the twin-accumulator hydro-pneumatic suspension system gives worthwhile improvements in ride comfort compared with the single accumulator hydro-pneumatic suspension, and it is more suitable for off-road vehicle.

Combat Vehicle Dynamic Load Tests in the Aspect of the Operation Safety

Combat Vehicle Dynamic Load Tests in the Aspect of the Operation Safety

Numerical and experimental investigation on stochastic dynamic load of a heavy duty vehicle

Numerical simulation and field test are used to investigate tire dynamic load. Based on multi-body dynamics theory, a nonlinear virtual prototype model of heavy duty vehicle (DFL1250A9) is modeled. The geometric structural parameters of the vehicle system, the nonlinear characteristics of shock absorber and leaf springs are precisely described. The dynamic model is validated by testing the data, including vertical acceleration of driver seat, front wheel, intermediate wheel and rear wheel axle head. The agreement between the response of the virtual vehicle model and the measurements on the test vehicle is satisfactory. Using the reliable model, the effects of vehicle speed, load, road surface roughness and tire stiffness on tire dynamic load and dynamic load coefficient (DLC) are discussed. The results demonstrate that the proposed model can offer efficient and realistic simulation for stochastic dynamic loads, so as to investigate vehicle road-friendliness.

Evaluation of dynamic vehicle axle loads on bridges with different surface conditions

Vehicles generate moving dynamic loads on bridges. In most studies and current practice, the actions of vehicles are modelled as moving static loads with a dynamic increase factor, which are obtained mainly from field measurements. In this study, an evolutionary spectral method is presented to evaluate the dynamic vehicle loads on bridges due to the passage of a vehicle along a rough bridge surface at a constant speed. The vehicle–bridge interaction problem is modelled in two parts: the deterministic moving dynamic force induced by the vehicle weight, and the random interaction force induced by the road pavement roughness. Each part is calculated separately using the Runge–Kutta method and the total moving dynamic load is obtained by adding the forces from these two parts. Two different types of vehicle models are used in the numerical analysis. The effects of the road surface roughness, bridge length, vehicle speed and axle space on the dynamic vehicle loads on bridges are studied. The results show that the road surface roughness has a significant influence on the dynamic vehicle–bridge interaction. The dynamic amplification factor (DAF) and dynamic load coefficient (DLC) depend on the road surface roughness condition.

Calculation of dynamic impact loads for railway bridges using a direct integration method

This paper introduces railway bridge assessment in the UK and the concept of dynamic impact loads. The dynamic impact loads demonstrated in the codes of practice in several other countries have been reviewed and have been found to be significantly different in the different codes. A technique for calculating dynamic impact load using a direct integration method has been developed. In many cases, the mass of the train may be similar to the mass of the bridge in heavy railway bridges but the mass of the vehicle is normally neglected in an analysis due to complexities in computation. Time-varying non-linear mass models are employed to reflect the effect of moving vehicle mass. An existing prototype bridge has been selected to compare results from the codes of practice and the technique developed in this study. The correlation between vehicle speed, axle load, and dynamic impact load has been investigated.

Multiple vehicle axle load identification from continuous bridge bending moment response

The identification of multiple vehicle dynamic axle loads on multi-span continuous bridge is presented. The objective of the present study was to develop a practical technique to determine dynamic axle loads of multiple vehicles based on the measured bridge response. Based on the inverse problem of turning bridge responses into time-varying point loads, the solution can be determined using least squares regularization optimization. The updated static component (USC) technique is adopted to improve the accuracy and eliminate the difficulty of an optimal regularization selection. The computer simulation and experimental studies were conducted to investigate the effectiveness of the proposed method. A scaled model of a three-span, continuous bridge and two scaled 2-axle vehicles were designed, constructed and fabricated in the laboratory. Various moving schemes of multiple vehicle travel including following, overtaking and side-by-side movements were considered. The actual dynamic axle loads of the model vehicles during the travel were directly monitored and used in accuracy evaluation. From the obtained results, it is observed that the USC technique effectively improved the accuracy and robustness of the problem, particularly in correction of the absence of identified axle loads around the internal bridge supports. The method is robust and accurately identifies every dynamic axle load for all moving schemes of vehicles. No conflict of the identified axle loads during axle overlapping and passing the bridge support is observed because the axle loads are identified independently and controlled by static influence lines from the USC algorithm. The comparison between the measured and reconstructed bending moments indicates that the approach is correct. The accuracy of identified dynamic axle loads for all cases of study is within a relative percentage error of 13%.

Weigh-In-Motion studies using strip-type sensors: the preliminary results

The various conditions of dynamic vehicle tire forces on pavement loading have been investigated by using strip type commercially available piezo-electric Weigh-In-Motion (WIM) sensors. Usually, the WIM load is found by empirically relating the peak voltage of the signal to the static wheel weight, and the area under the signal and the vehicle speed are not considered. A formula considering the area under the WIM signal and the moving load is presented. Whether or not static calibration factor of strip type sensors is sufficient to calculate the vehicle dynamic load is determined and a quasi-static vehicle pass over calibration methodology for future experiments is suggested. This paper also reviews the detailed description of the research carried out on existing WIM sensors and related systems.

Fuzzy logic modeling of deflection behavior against dynamic loading in flexible pavements

Flexible pavements are especially affected by moving vehicles. As a result of the moving vehicles, the pavement starts to deteriorate. For the determination of the structural capacity of the pavement, non-destructive testing equipments are used. These are mainly Benkelman beam, Dynaflect and falling weight deflectometer (FWD). In such a process, the most important thing is to analyze the collected data. In general, linear elastic theory and finite element method are used for this purpose. Since linear elastic theory and finite element method are time consuming, a fuzzy logic approach is used for the elimination of this drawback during the course of this study. Results indicate that the fuzzy logic approach can be used for the modeling of the deflection behavior against dynamic vehicle loading for flexible pavements. The fuzzy model is able to predict the deflection behavior against dynamical loading. The new approach can capture the non-linearity of surface deflection behavior.