重型载货汽车车架结构模态分析

有限元模态分析方法是辨识车辆结构动态性能的一种有效手段,所以为得到重型载货汽车车架结构的动态特性,本文以板壳单元为基本单元,建立了车架结构有限元模态分析模型,并采用NASTRAN有限元分析软件,计算了该车架在自由状态下的模态参数.同时,分析了载货汽车车轮和传动轴的不平衡质量产生的激励,并对车架的结构动态性能进行了评估.结果表明,在不同的行驶速度下,车轮和传动轴不平衡质量激励频率与车架的一阶扭转振动频率、倍频、一阶横向弯曲振动频率及车架11～18阶振动频率接近,使车架易产生共振现象.该研究为进一步改进车架结构提供了理论依据.

Modal Structural Analysis for Frame of a Heavy Truck

Modal finite element analysis （FEA） is an effective mean for identifying the dynamic performance of vehicle structure. A FEA modal analysis model based on shell elements was built for obtaining the dy- namic characteristics of the structure of a heavy truck frame. Modal parameters of the frame under free conditions were obtained from the modal analysis using FEA Software NASTRAN. Meanwhile, the exci- tation caused by the unbalance of the wheel and drive shaft was analyzed. The structure dynamic perform- ance of the frame was evaluated. The results showed that the exciting frequency caused by the unbalance of the wheel and drive shaft under different speed was closed to the first torsional vibration frequency, double frequency, the firsttransverse bending torsional vibration frequency and the 11th to 18th vibration frequen- cy of the frame, which caused the of the frame. The research provided reference for the further improve- ment of frame structure.