果蝇鸣声信号结构分析与时频子波建模

钢轨短波波磨主要出现在地铁小半径曲线路段上，波长范围一般为20mm～100mm，是铁路行业面临的一个比较普遍的问题。通过锤击法对某地铁曲线段线路的GJ-32扣件、先锋扣件与科隆蛋扣件进行了垂向、横向频率响应特性测试，同时利用CAT波磨测试仪测试了曲线段的波磨情况，对小半径曲线段钢轨短波波磨进行研究。通过现场调查和试验测试得出如下结论：（1）、先锋扣件轨道结构形式下钢轨的横向551Hz“pinned-pinned”共振频率是导致小半径曲线段波长为20mm左右的钢轨短波波磨的一个重要原因；（2）、小半径曲线路段上不同扣件结构形式下钢轨的垂向弯曲共振不是曲线段出现波磨的主要原因。

EMA of an aluminum plate under sound-induced excitation

For large solar panels of spacecraft in a free-hanging conditions, as a result of the structure＇s ultra-low frequency, large displacement and dense local modes, the conventional approach has inspired a variety of shortcomings, such as： low MAC and poor system stability. Based on these difficulties and in the context of modal test for large solar panels of spacecraft, this paper puts forward a non - contact sound-induced exciting method. Meanwhile, the paper designs and construct an experimental modal test, in which a rectangular aluminum plate is excited by a speaker, and the modal parameters are identified. At last, the results are compared with ones identified by traditional methods. The results provide a guiding significance for the experimental design and identification of solar panels and other large spacecrafts.