Full Vehicle Analysis Research Articles

Numerical modeling of axial fan noise in fuel-cell electric truck: from component to full-vehicle analysis

This paper presents a comprehensive approach to predict the noise generated by an axial fan in electric vehicles, which is more noticeable due to the absence of combustion engines. Such cooling fans require stronger cooling performance due to increased demand for heat dissipation, resulting in even higher noise levels. A numerical model for fan noise in a fuel-cell electric vehicle (FCEV) is proposed with two steps: component-level and full-vehicle level models. At component level, Lattice Boltzmann Method (LBM) is employed for aeroacoustics simulation, determining the component sound power level (SWL). At full vehicle level, statistical energy analysis (SEA) is utilized to estimate the sound pressure level (SPL) inside the vehicle cabin, particularly at the driver's ear locations. The noise sources in the full vehicle model, were characterized from the component level SWL, as monopole sources. The model is validated by comparing the numerical predictions with the experimental measurements of the SWL in a hemi-anechoic chamber and the SPL in the cabin. Good agreements were obtained between numerical results and measurement results, demonstrating the effectiveness of the model. This allows for faster and more accurate virtual NVH design validations on large and complex systems where prototype measurements are difficult to conduct.

Vehicle Cornering Performance Evaluation and Enhancement Based on CAE and Experimental Analyses

A full-vehicle analysis model was constructed incorporating a SLA (Short Long Arm) strut front suspension system and a multi-link rear suspension system. CAE (Computer Aided Engineering) simulations were then performed to investigate the lateral acceleration, yaw rate, roll rate, and steering wheel angle of the vehicle during constant radius cornering tests. The validity of the simulation results was confirmed by comparing the computed value of the understeer coefficient (Kus) with the experimental value. The validated model was then used to investigate the steady-state cornering performance of the vehicle (i.e., the roll gradient and yaw rate gain) at various speeds. The transient response of the vehicle was then examined by means of simulated impulse steering tests. The simulation results were confirmed by comparing the calculated values of the phase lag, natural frequency, yaw rate gain rate, and damping ratio at various speeds with the experimental results. A final series of experiments was then performed to evaluate the relative effects of the cornering stiffness, initial toe-in angle, and initial camber angle on the steady-state and transient-state full-vehicle cornering handling performance. The results show that the handling performance can be improved by increasing the cornering stiffness and initial toe-in angle or reducing the initial camber angle.

Research of Automobile Tire Vertical Stiffness Optimization Method on the Basis of ADAMS/Car

Because Tire not only impact on the handling stability of vehicle but also impact on the ride comfort, it is more practical significant that tire vertical stiffness parameters on handling stability and ride of vehicle impact is considered synthetically than considering handling stability and ride singly. In this paper, full vehicle model was built on the basis of ADAMS/Car. The vertical stiffness of tire was only changed and other parameters remain unchanged, then full vehicle analysis was carried out to get the simulation curves. The impact of the vertical stiffness of tires on the handling and stability and ride comfort was obtained from the curves of simulation. The tires of optimized vertical stiffness can be obtained from the comparison of simulation results. Analytical results can be conductive to designing and producing the tire.

Comparison of the optimum designs of center pillar assembly of an auto-body between conventional steel and ahss with a simplified side impact analysis

This study compares the optimum designs of center pillar assembly with advanced high-strength steel (AHSS) to that of conventional steel for crashworthiness and weight reduction in side impacts. A simplified side impact analysis method was used to simulate the crash behavior of the center pillar assembly with efficient computing time. Thickness optimization aims to perform an S-shaped deformation of the center pillar toward the cabin to reduce the injury level of a driver in a crash test. Center pillar members were regarded as an assembly of parts that are fabricated with tailor-welded blanks, and the thickness of each part was selected as a design variable. The thickness variables of parts that have significant effects on the deformation mechanism were extracted as the main design variables for thickness optimization based on the results of a sensitivity analysis with design of experiments. The optimization condition was constructed to induce an S-shaped deformation mode and reduce the weight of the center pillar assembly. An optimum design was obtained after several iterations with response surface methodology (RSM). Optimization was first performed with conventional steel and then with AHSS with the same procedure to optimize the crashworthiness of the center pillar assembly. After thickness optimization, optimum designs were applied to the full vehicle analysis to evaluate the validity of the optimization scheme with the simplified side impact analysis method. Then, the crashworthiness of optimum designs with conventional steel and AHSS were compared using the full vehicle analysis. This comparison demonstrates that AHSS can be more effectively utilized than conventional steel to obtain a lightweight design of an auto-body with enhanced crashworthiness.

Analysis of the Impact of Unloaded Radius of Tire on the Handling and Stability of Automobile on the Basis of ADAMS/CAR

Because the brake and turn of automobile is completed by transmitting the force and torque to the ground through the tire, tires can influence the handling and stability of automobile. The impact of the unloaded radius of tire on the handling and stability of automobile was studied on the basis of ADAMS/CAR in this paper. The unloaded radius of tire was only changed and other parameters remain unchanged, then full vehicle analysis was carried out to get the simulation curves. The impact of the unloaded radius of tires on the handling and stability of automobile was obtained from the curve of simulation. The results of simulation are conducive to designing the shape and dimension of tires.

Virtual Proving Ground - an integrated technology for full vehicle analysis and simulation

Virtual Proving Ground (eta/VPGTM) is a unique and integrated computer aided engineering (CAE) technology to conduct full vehicle real time, nonlinear dynamic analyses and simulations. The utilisation of this new technology can greatly improve the analytical results as compared with other conventional CAE tools. VPG can expand CAE applications into many special and important fields where the current CAE methods have no or only limited applications. It can also greatly reduce vehicle development costs and time. Presented in this paper are the VPG concept and the advantages it provides for full vehicle system analysis, simulation, and prototyping. Application examples of vehicle durability and fatigue analysis, NVH analysis, vehicle dynamics analysis and crashworthiness and safety analysis are also provided. Other VPG applications such as road load generation, and CPU requirements for VPG simulations are briefly discussed in the paper.