Investigation into Improvement for Anti-Rollover Propensity of SUV

Currently, many research from domestic and foreign on improving anti-rollover performance of vehicle mainly focus on the electronic control of auxiliary equip- ment, do not make full use of suspension layout to optimize anti-rollover performance of vehicle. This investigation into anti-rollover propensity improvement concentrates on the vehicle parameters greatly influencing on anti-rollover propensity of vehicle. A simulation based on fishhook procedure is used to perform design trials and evaluations aimed at ensuring an optimal balance between vehicle＇s design parameters and various engineering capacities, the anti-rollover propensity is optimized at the detailed design stage of a new SUV model. Firstly a four-DOF theoretical kinematic model is established, then a complete multi-body dynamics model built in ADAMS/car based on the whole vehicle parameters is correlated to the objective handing and stability test results of a mule car. Secondly, in fish- hook test simulations, the Design of Experiments method is used to quantify the effect of the vehicle parameters on the anti-rollover performance. By means of the simulation, the roll center height of front suspension should be more than 30 mm, that of rear suspension less than 150 mm, and the HCG less than 620 mm for the SUV. The ratio of front to rear suspension roll stiffness should be ranged from 1.4 to1.6 for the SUV. As a result, at the detailed design stage of product, the anti-rollover performance of vehicle can be improved by optimizing chassis and integrated vehicle parameters.

Vibration Characteristics of Framed SUV Cab Based on Coupled Transfer Path Analysis

The vibration transmission paths in a sport-utility vehicle with a frame structure were used to evaluate the coupled vibra-tion of each vibration transmission link.This method was based on the transmission path of an“engine-powertrain mount system-frame-vehicle body suspension-body-driver seat rail,”and the research objective was to improve the vibration char-acteristics of the cab.This coupled transfer path analysis combined analysis and experiment to establish the vehicle vibration transmission path model and a finite element simulation model.With this method,the vibration level of the driver’s seat rail was reduced and engineering practice was effectively used to improve the vibration characteristics of the cab.This method was applied to a framed SUV cabin.

Uncertainty Optimization Design of a Vehicle Body Structure Considering Random Deviations

In vehicle body manufacturing,there are small differences between the actual value and design value of,for example,plate thickness and material characteristics.This is caused by the processing technology,environment and other uncertain factors.Therefore,the performance of the vehicle body processed according to the deterministic optimization solution fluctuates.The fluctuations may make structural performance fail to meet the design requirements.Thus,in this study,an optimization design is executed with 6σrobustness criteria and a Monte Carlo simulation single-loop optimization strategy based on the radial basis function neural network approximate model considering deviations in plate thickness,elastic modulus,and welding spot diameter,which is called the uncertainty optimization design method.As an example,considering the bending stiffness,torsion stiffness,and first-order frequency as constraints,the method is applied to the lightweight design of a car body structure,and the reliability of deterministic optimization design and uncertainty optimization design is compared.The results demonstrate that the uncertainty optimization design solution is effective and feasible without lowering the static stiffness and modal performance,and the weight is reduced.