小型机动平台车体动态特性分析与减振优化

Dynamic Characteristics Analysis and Improvement of Body for Mini Mobile Platform

车架挂发动机(即车体)是机动平台的关键部件,其动态特性直接影响整个平台的振动舒适性。利用UG4.0对某国产机动平台进行三维建模,用Hypermesh建立车架、车体的有限元模型,并导入到MSC.Nastran中进行了自由模态分析,通过试验分析了车架及车体的振动特性并验证了有限元模型的准确性。结合模态分析结果,讨论了路面激励和发动机激励对车体动态特性的影响,发现车体结构设计有不足之处——发动机1阶往复惯性力的频率会导致车体共振。提出了通过修改车体头部左右两边上管及下管的管径、管壁厚和在其夹角处设置加强管等3种改进方案。分析表明,增大车体头部左右上管和下管的管径可明显改善车体的结构动态特性,大大提高了整车的振动舒适性。

The frame hang engine that is the body with engine is the key component of the mobile platform,and its dynamic characteristics has direct affect on the platform＇s vibration comfort.A three-dimensional model of some domestic mobile platform was built with UG4.0,and its finite-element model was also developed by using Hypermesh,and then imported it to Msc.Nastran for free modal analysis.The frame and body vibration characteristic was analyzed after related tests were done,and the accuracy of the finite element model was verified.According to modal analysis results,the influence of Road excitation and engine excitation on the body was studied,and the deficiency of structure design is that the frequency of first-order reciprocation force can lead to resonance.For performance improvement,the diameters and thickness of lower and upper arms mounted on the body front part were increased,and strengthening pipe was added.Study shows,after modification,the first method is most useful for improving structure dynamic performance and vibration comfort.