噪声与振动控制
譟聲與振動控製
조성여진동공제
NOISE AND VIBRATION CONTROL
2015年
1期
68-72
,共5页
振动与波%传感器配置%模态分析%模态置信度%无人直升机
振動與波%傳感器配置%模態分析%模態置信度%無人直升機
진동여파%전감기배치%모태분석%모태치신도%무인직승궤
vibration and wave%sensor placement%modal analysis%modal assurance criterion%unmanned helicopter
传感器配置是结构动态测试的一项重要的技术措施，其效果决定了结构的各阶主要测试模态的有效程度。由此，首先对结构仿真模型进行预先的主元素分析，优化传感器的布置。在结构有限元模型（FEM）中，对模型固有特性进行分析，确认重要的结构模态和结构动态测试目标。利用Guyan缩减方法对模型的自由度进行主从划分；选取感兴趣的结构振型的主自由度，对应从有限元模型中提取缩减的“试验模型”。针对提取的缩减模型重新开展模态分析，采用模态置信度（MAC）指标评估各阶振型之间的相关性，进而量化并直观显示传感器的配置效果。对某型号无人直升机机身结构进行地面振动试验。通过从仿真模型中选取合适的振型主元，改进传感器的配置，能保证试验中获得期望的结构测试模态，验证了利用结构仿真模型在动态测试之前预先进行传感器优化配置的效果。
傳感器配置是結構動態測試的一項重要的技術措施，其效果決定瞭結構的各階主要測試模態的有效程度。由此，首先對結構倣真模型進行預先的主元素分析，優化傳感器的佈置。在結構有限元模型（FEM）中，對模型固有特性進行分析，確認重要的結構模態和結構動態測試目標。利用Guyan縮減方法對模型的自由度進行主從劃分；選取感興趣的結構振型的主自由度，對應從有限元模型中提取縮減的“試驗模型”。針對提取的縮減模型重新開展模態分析，採用模態置信度（MAC）指標評估各階振型之間的相關性，進而量化併直觀顯示傳感器的配置效果。對某型號無人直升機機身結構進行地麵振動試驗。通過從倣真模型中選取閤適的振型主元，改進傳感器的配置，能保證試驗中穫得期望的結構測試模態，驗證瞭利用結構倣真模型在動態測試之前預先進行傳感器優化配置的效果。
전감기배치시결구동태측시적일항중요적기술조시，기효과결정료결구적각계주요측시모태적유효정도。유차，수선대결구방진모형진행예선적주원소분석，우화전감기적포치。재결구유한원모형（FEM）중，대모형고유특성진행분석，학인중요적결구모태화결구동태측시목표。이용Guyan축감방법대모형적자유도진행주종화분；선취감흥취적결구진형적주자유도，대응종유한원모형중제취축감적“시험모형”。침대제취적축감모형중신개전모태분석，채용모태치신도（MAC）지표평고각계진형지간적상관성，진이양화병직관현시전감기적배치효과。대모형호무인직승궤궤신결구진행지면진동시험。통과종방진모형중선취합괄적진형주원，개진전감기적배치，능보증시험중획득기망적결구측시모태，험증료이용결구방진모형재동태측시지전예선진행전감기우화배치적효과。
Sensors placement is a key step in the dynamic testing of structures. In this article, preliminary master-ele-ments analysis of structural simulation models was done to optimize the sensors placement. A finite element model (FEM) of the structures was prepared. Structural modal analysis was performed to determine the key modals and the objective of the dynamic testing of the structures. Master-slave degrees of freedom (DOFs) of the structural finite element model were then classified using the Guyan reduction method. The master DOFs for the interesting vibration modes corresponding to the ex-tracted“reduced test model”from the aircraft finite element model were defined. Modal analysis for the reduced model was repeated. Modal assurance criterion (MAC) was used to assess the correlation among the calculated mode shapes of the re-duced model. The effects of optimal sensor placement were eventually quantified and clearly displayed. An actual example was demonstrated for the ground vibration test (GVT) of an unmanned helicopter fuselage. The optimal placement of testing sensors through selecting the suitable master vibration modes of FEM assured that the expected fuselage vibration modes from the GVT could be obtained. This verified the effectiveness of the structural simulation model for the optimization of the sensor placement before the dynamic testing.
