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A new tyre vertical vibration model is proposed for the determination of the tyre vertical mechanical properties. The tyre is simplified as a vibration system composed of several discrete belt elas...

An energy-based fatigue damage model was used to estimate the fatigue life of a mining truck welded frame. Experimental work including monotonic and strain-controlled cyclic loading was conducted to characterize the base metal and the weld. A dynamic model was created for the whole truck in the ADAMS software to estimate the force histories applied to the frame in different maneuvers over a simulated road. A Finite element (FE) model was generated for the welded frame and the cyclic loading obtained from the dynamic model was applied to the FE model. The FE model was used to find the stress and strain responses, which were then used to calculate the strain energy and the fatigue life. The fatigue life predictions for the frame agreed well with observations of the truck’s in-service failure.

In order to reduce frame redundant weight caused by the traditional experience design and delay the crack initiation occurrences at local positions during early service period, a structural weight and lifetime co-optimization method for frame of a mining dump truck based on Kriging approximation model was proposed. Considered as the most sensitive factor to the frame fatigue life and weight, the thickness of several steel plates was chosen as design variables in terms of un-allowed change of structure shape, while achieving weight reduction and improving fatigue life were together regarded as the optimization targets. An experiment design with 20 sample points obtained by the Latin hypercube sampling method was conducted to figure out the sensitivity of design variables, whose response values were acquired through repeated simulations. Those data were supposed to set up the approximation model constructed based on the Kriging interpolation technique and its fitting precision was certified by comparison of the finite element computational results and the approximation model calculated ones. The non-dominated sorting genetic algorithm II (NSGA-II) was utilized to optimize the thickness of the steel plates based on the approximation model. The tolerance between the results of the simulation and the approximation model was less than 1% when using the optimal design variables and the weight of the optimized frame was lessened by 22.3% while the minimum fatigue life and maximum static stress were only decreased by 3.8% and 4.6%, compared with the initial frame. These optimized results were acceptable for frame lightweight almost without expense of fatigue life and static strength.

In light of the fact that computational results based on commonly used turbulence models are unsatisfactory, a modified LRN $${k-\varepsilon}$$ turbulence model is proposed. The modified concept includes the introduction of the total stress limitation idea and separation-aware model. With the help of this concept, the transport effects of total turbulent shear stress are taken into consideration and the boundary separation is detected. Thus, the model’s ability to simulate laminar-turbulent transition, which is an essential feature of the flow field around vehicles, is improved. The Ahmed model and its corresponding experimental data are introduced to validate and evaluate the modified LRN $${k-\varepsilon}$$ model. Several commonly used turbulence models are also introduced as comparisons. Computations are carried out by the ISIS-CFD flow solver. This work shows that predictions achieved by the modified LRN $${k-\varepsilon}$$ model give a better agreement with experimental data than other solutions.

Large-eddy simulation method was employed to compute the buffeting noise of a simple deep cavity model. Compared with the results of wind tunnel experiments, the numerical results coincided well with the experimental results, which further validated the correctness of Large-eddy simulation method. Large-eddy simulation method was employed to calculate automobile side-window buffeting noise when the side-window near the driver was partially opened by 25%, and the road test data validated its correctness. The flow field results were loaded to the finite element model to compute dynamic response of the car’s windows, the weak vibration of windows was excited by the air energy exchange between interior and exterior when the car at high speed. Acoustic radiation of window structure, sound pressure levels of field points in the frequency domain, panel acoustic contribution analysis of window structure were obtained by the vibration solution for the windows. The results demonstrated that the noise radiation caused by the windows’ vibration aroused the acoustic response significantly at some certain frequencies, although side-windows buffeting noise dominated in the low frequency domain. The rear window acoustic contribution accounted for the major part of the total pressure. Compared with other three side-windows, the contribution of the partially opened side-window to the total pressure was the greatest.

Flow over an open side window in a car exhibits similar characteristics as the flow over an open cavity. Computational Fluid Dynamics (CFD) simulation over a cavity was done as a benchmark. The unsteady flow simulation was carried out using Scale Adaptive Simulation (SAS) turbulence model. The benchmark results, frequency and sound pressure levels of feedback and resonance modes, all well matched with the experimental data. Then, with the right rear window, for example, the mechanism of the side window buffeting was investigated. The simulation results show that side window buffeting noise is generated by large scale vortices and in low frequency. Furthermore, buffeting noise characteristics under several patterns of side windows opening were also numerically investigated. As a result, rear window buffeting noise is more severe than that of front window when one window open, and combination pattern of side windows open can reduce buffeting noise. To decrease the interior noise and improve car ride comfort, four suppression measures through adding a side window weather deflector at the A-pillars, constructing a cavity at the B-pillars, combination of the front and rear windows and installing a row of square cylinder deflector at the B-pillars were also studied, respectively. In conclusion, certain noise reduction can be achieved through four passive control methods.

Flow passing a vehicle may lead to the increase of the cabin interior noise level through a variety of mechanisms. These mechanisms include vibrations caused by aerodynamic excitations and re-radiation from the glass panels, exterior noise transmitted and leaked through door seals including gaps and glass edge, and transmission of airborne noise generated by the interaction of flow with body panels. It is of vital importance to predict both the flow fields and the acoustic sources around the vehicle to accurately assess the impact of wind induced noise inside the cabin. In the present study, an unstructured segregated finite volume model was used to calculate the flow fields in which a hexahedron grid is used to simplify the vehicle geometry. A large eddy simulation coupled with a wall function model was applied to predict the exterior transient flow fields. The mean flow quantities were thus calculated along the symmetry plane and the vehicle’s side windows. A coupled FEM/BEM method was used to compute the vehicle’s interior noise level. The total contribution of the interior noise level due to the body panels of the vehicle was subsequently analyzed.

The high aerodynamic noise induced by automotive air conditioning systems has important effects on the ride comfort, and the centrifugal fan is the largest noise source in these systems. It is very important to reduce the aerodynamic noise generated by the centrifugal fan. The flow field and the sound field on the whole centrifugal fan configuration have been carried out using the computational fluid dynamics. Simulation results show that the sound pressure level near the outlet of the centrifugal fan is too high. Based on the relationship between flow characteristics and the aerodynamic noise, four parameters of the centrifugal fan, i.e., impeller blade’s outlet angle θ, volute tongue’s gap t, collector inclination angle β, and rotating speed n, were selected as design variables and optimized using response surface methodology. While keeping the function of flow rate unchanged, the peak noise level is reduced by 8 dB or 10.8%. The noise level is satisfactorily reduced.

Cracks of A-type frame of a mining dump truck have occurred before exceeding structural fatigue design life. In order to accurately predict location of cracks and fatigue life of this component and find the reasons, a fatigue life analysis method combined with experiment and simulation is presented. Compared with the tested peak stress and simulated maximum stress of A-type frame under full loadings, the difference is acceptable so that the accuracy of finite element model of A-type frame is guaranteed. The rigid and flexible hybrid model of whole truck is built to get the stress situation based on modal stress recovery method, taking flexible body of A-type frame into account. Compared with the tested acceleration, the vertical simulated acceleration of the seat is acceptable, which ensures the validity of rigid and flexible hybrid model of this mining dump truck. According to the linear Palmgren–Miner hypothesis and S–N curve, fatigue life of A-type frame is assessed. The results show that the predicted cracks location and fatigue life of A-type frame is well accordance with the practical situation. To extend life of A-type frame, a modified structure is presented in this paper.

This paper is concerned with prediction of heat dissipation effect by establishing a 3d geometric model of the radiator group for a ribbon-tubular radiator of a mining dump-truck. By using the CFD approach the airflow characteristics of the radiator group are numerically calculated, and the resistance characteristic and heat transfer performance are analyzed thus the matching point of the fan is calculated, and the heat transfer performance of the water-side is simulated. Then, according to the relative heat transfer theory, the inlet and outlet water temperature of the radiator group under idling condition is obtained by analytical method. The experiment is done subsequently. The maximum deviation rate between the results of the simulation and the experiment is 6.4%, which can meet the engineering requirement and well predicts the heat dissipate performance of the radiator group. The result indicates that by combining the CFD numerical simulation with the analytical method the heat dissipation of the radiator group can be predicted effectively.

Experimental and numerical investigations are conducted to investigate the noise induced by a subsonic flow over a cavity. Particular attention is focused on the problem of low-frequency pressure oscillations inside the cabins of automobiles with open sunroofs. The mechanisms of buffeting noise are examined by considering a model cavity. Extensive experiments are performed to validate the computational scheme developed in the present study. This computational scheme is used for designing generic deflectors for reducing buffeting noise. Experimental and computational results show that the traditional generic deflector is unable to reduce the buffeting noise when the flow velocity is sufficiently high. However, a vented deflector allows the effective control of the buffeting noise at relatively high flow speeds.

Aiming at precisely predicting fatigue life for frame of the 220t mining dump truck, a fatigue life analysis method is presented, integrating multibody dynamic analysis and finite element method. The force of main joints at frame are measured from the multibody dynamic model, whose road is restructured based on ISO/TC108/SC2N67. According to GB/T27025-2008, the dynamic stress test of the whole truck is implemented to obtain the peak stress of the mainly forced area, which is compared with the simulated stress. It is found out that the error is allowable so that the accuracy of the finite element model is definitely ensured. The quasi-static stress analysis method is employed to acquire stress influence coefficient under unit load, which is associated with load histories of the frame to get the dangerous stress area. The fatigue life of the frame is calculated on the basis of Palmgren–Miner damage theory. It is turned out that the minimum life area of the frame is located at the frame joints of suspension, which matches the practice.

A surrogate model-based aerodynamic shape optimization method applied to the wind deflector of a tractor-trailer is presented in this paper. The aerodynamic drag coefficient of the tractor-trailer with and without the wind deflector subjected to crosswinds is analyzed. The numerical results show that the wind deflector can decrease drag coefficient. Four parameters are used to describe the wind deflector geometry: width, length, height, and angle. A 30-level design of experiments study using the optimal Latin hypercube method was conducted to analyze the sensitivity of the design variables and build a database to set up the surrogate model. The surrogate model was constructed based on the Kriging interpolation technique. The fitting precision of the surrogate model was examined using computational fluid dynamics and certified using a surrogate model simulation. Finally, a multi-island genetic algorithm was used to optimize the shape of the wind deflector based on the surrogate model. The tolerance between the results of the computational fluid dynamics simulation and the surrogate model was only 0.92% when using the optimal design variables, and the aerodynamic drag coefficient decreased by 4.65% compared to the drag coefficient of the tractor-trailer installed with the original wind deflector. The effect of the optimal shape of the wind deflector was validated by computational fluid dynamics and wind tunnel experiment.

For study the law of urban buildings, in particular, the buildings at both roads’ sides in crossroads impacting on the diffusion of automobile exhaust, using CFD, combined with meteorological wind，simulates a crossroads automobile exhaust diffusion processing during waiting 35s. The results are following: in poor circulation areas, CO volume fraction in the buildings near-Earth space is up to 1.0e-7 and more than 100 times average value of the entire study area, so buildings structural layout has great influence. After Analysis, propose that local meteorological wind direction and speed should be considered and different height gradient design should be selected in buildings structural layout, so that the exhaust spread rapidly and drift to the urban high altitude, in order to improve air quality.

Establishes 3d numerical simulation model of water side and air side for ribbon-tubular radiator, studies effect of air velocity on air side heat transfer capacity and drag characteristics by using CFD method, based on double side 3d simulation result, and then calculates the import and export water temperature of the high low temperature radiator group with procedure. The calculated water temperatures are coinciding with experimental data. Then analyzes the influence rule of different wave combinations to the radiator group performance by the method of simulation and procedure calculation, the result is reference theory for the structure optimization and matching of the radiator group.

Various return oil channels of a large self-dumping truck hydraulic tank don’t work synchronously brings the exit temperature fluctuations, traditional heat balance calculation can’t get some point temperature in tank, so it can’t be used to analyze temperature fluctuations. Selecting RNG k-εturbulent model and using CFD method，this paper analyzes flow field in the hydraulic tank of a certain large self-dumping truck at first, then according the principle of enhancing heat exchange, proposes two structure improved schemes, and contrasts the simulation result of two schemes, The results show that the two improved schemes reduce the tank exit temperature fluctuations and the high local temperature at different degrees, and the temperature fluctuations reduce range of the best scheme is 86.51% when the initial hydraulic oil temperature is 40°C.

To overcome the disadvantages of the conventional federated Kalman filter, a fuzzy Kalman filter based on a genetic algorithm (GA) is presented in this paper and applied in the information fusion of the Global Positioning System—dead reckoning vehicle integrated navigation system. The noise covariance and information distribution coefficient of the local filtering are modified online by the fuzzy logic adaptive controller in order to make the Kalman filtering optimal and to improve the positioning accuracy of the integrated navigation system. The acquisition of the membership function of a fuzzy controller usually relies to a great extent on empirical and heuristic knowledge. In this paper, the GA is used to optimize the fuzzy membership function and obtain the optimal or suboptimal control effect. The results of simulations demonstrate the feasibility and effectiveness of the method.

The external flow field of Ahmed model is simulated by Fluent, and is verified with experiments. On that basis, The Ahmed model with different rear slant angles and ride heights are simulated. Then the reasons for the lift force changing are analized, and the flow field behind the Ahmed model of three different rear slant angles are compared with each other. It shows that the results from Realizable k−e are more accurate than the others which are compared in this paper. During the rear slant angle changing from 0 degree to 30 degree, the lift force increase linearly with the angle increasing. With the growth of ride heights, the lift force increase exponentially.