某SUV前副车架强度与疲劳性能仿真与试验研究

SIMULATION AND EXPERIMENTAL STUDY ON STRENGTH AND FATIGUE PERFORMANCE OF A SUV FRONT SUBFRAME

为了提高某前置前驱SUV前副车架的可靠性,对其进行强度与疲劳分析,综合运用有限元方法、多体动力学理论、强度分析理论、疲劳分析理论,通过建立的前副车架三维模型与多体动力学刚柔耦合模型,分析副车架在不同工况下的强度和疲劳特性,并对副车架进行强度及疲劳试验。仿真结果表明,在直线行驶、转向工况下转向器连接点位置变形量分别为2.924 mm、3.411 mm,稳定杆及扭力臂位置变形量分别为3.383 mm、2.695 mm。强度试验结果表明,在直线行驶、转向工况下转向器连接点位置变形量分别为3.263 mm、3.622 mm,试验数值较仿真结果分别高出11.59%、6.19%;稳定杆连接点及扭力臂连接点变形量分别为3.538 mm、2.957 mm,试验结果较仿真数值分别高出4.58%、9.72%。结果表明试验结果与仿真结果差别并不明显,副车架在各点处变形量符合设计。副车架疲劳试验结果表明,扭力臂疲劳试验80万次、制动力疲劳试验40万次、侧向力疲劳试验80万次后副车架未出现裂纹及塑性变形,副车架疲劳特性满足要求。

In order to improve the reliability of the front subframe of a front drive SUV,the strength and fatigue characteristics of the subframe under different working conditions are analyzed by comprehensively using the finite element method,multi-body dynamics theory,strength analysis theory and fatigue analysis theory,and through the established threedimensional model of the front subframe and the rigid flexible coupling model of multi-body dynamics.The strength and fatigue tests of the subframe are carried out.The simulation results show that the deformation of steering connection point is 2.924 mm and 3.411 mm respectively under straight driving and steering conditions,and the deformation of stabilizer bar and torsion arm is 3.383 mm and 2.695 mm respectively.The strength test results show that,in the straight driving and steering conditions,the deformation of the steering point is 3.263 mm and 3.622 mm respectively,which are 11.59%and 6.19%higher than the simulation results.The deformation of the connection point of the stabilizer bar and the connection point of the torsion arm are 3.538 mm and 2.957 mm respectively.The experimental results are 4.58%and 9.72%higher than the simulation results respectively.The results show that there is no obvious difference between the experimental results and the simulation results,and the deformation of the subframe at each point conforms to the design.The fatigue test results of the subframe show that there are no cracks and plastic deformation in the subframe after 800 thousand torsion arm fatigue tests,400 thousand braking force fatigue tests and 800 thousand lateral force fatigue tests,indicating that the fatigue characteristics of the subframe meet the requirements.