汽车后扭力梁结构的模态分析

为揭示某汽车后扭力梁在实际道路激励工况下容易出现振动疲劳的机制,需要对结构固有振动特性进行分析。为了得到后扭力梁结构更为准确的固有振动特性,对模态试验中的悬挂位置、激励位置和测点位置的布置方式进行重点分析,并结合结构的实际情况进行优化。采用优化后的最佳模态试验法识别后扭力梁结构在自由-自由工况下的模态参数,得到结构固有频率和振型特征。通过对比可知：后扭力梁结构前10阶自由模态频率吻合很好,误差控制在6%内。这表明采用优化后的模态试验方案能够更为准确地识别结构的模态频率,得到结构固有振动特性。

Modal Analysis for Rear Torsion Beam on Car

The inherent vibration characteristic of rear torsion beam was used to analyze for revealing the mechanism easy to appear vibration fatigue when the car was suffered from actual road excitation.In order to get more accurate inherent vibration characteristic of the rear torsion beam,the suspension position,excitation position and the measuring point of modal test were firstly focused and optimized according to actual situation.Secondly,the structural natural frequency and vibration mode characteristics were achieved by using the optimal modal test method to identify modal parameters of rear torsion beam under free-free conditions.By contrasting with the finite element analysis results,the FE analysis for first-ten free modal frequencies matched with test,and the error was in 6%.It has verified that the optimization of the modal test scheme could acquire more accurate to identify the modal frequency of structure,and get structural inherent vibration characteristic.