基于响应面优化的客车后高地板骨架设计

Bus Rear High Floor Skeleton Design Based on Response Surface Optimization

在进行车身轻量化设计时可能会降低车身刚度,造成固有频率下降,车身在外部激励下容易产生共振。基于有限元法建立客车车身后高地板骨架总成模型,通过对模型的模态分析确定轻量化设计的可行性;随后建立优化模型并对构成零件的外廓尺寸和厚度进行参数化设置。在对模型进行优化之前,先通过敏感性分析剔除与优化目标相关性弱的参数,再用克里金法生成拟合优度满足要求的响应面模型,最后通过遗传算法寻优并生成3个候选点,参考候选点参数并结合生产实际对原模型参数进行调整,优化后的高地板骨架减重比例达16%。采集实车后高地板骨架在发动机全转速功率段的振动信号,信号的时域和频域分析结果表明,设计优化后的车辆后部振动特性正常,乘客的乘坐舒适性满足要求。

The lightweight design of the car body may reduce the body stiffness,resulting in a decrease in the natural frequency,and the body is susceptible to resonance under external excitation.In this paper,a model of the rear high floor skeleton assembly of the bus body is established based on the finite element method.The feasibility of the lightweight design is determined by modal analysis of the model.Subsequently,an optimization model is established and proceeded to parameter setting for the outer dimensions and thickness of the constituent car parts.Before the optimization of the model,the parameters with weak correlation to the optimization target were eliminated by sensitivity analysis.The response surface model with the required high fit was generated by Kriging algorithm.Finally,the genetic algorithm was used to optimize and generate three candidate points.Referring to the candidate point parameters and combining with the production practice to adjust the original model parameters,the optimized high floor skeleton weight reduction ratio reached 16%.The parameters of the original model were adjusted with reference to the parameters of the candidate points and combined with the actual production,and the weight reduction ratio of the optimized high floor skeleton reached 16%.The vibration signals of the high floor skeleton were collected from the rear of the vehicle at full engine speed.The results of the time and frequency domain analysis showed that the vibration characteristics of the rear of the vehicle were normal after the design optimization,which indicated that the passenger comfort was not affected..