直升机振动谱线在仿真分析中的转化方法研究

Study on the Conversion Method of Vibration Spectrum of Helicopter in Simulation Analysis

直升机平台的正弦加随机振动谱线无法直接做为边界条件施加在有限元模型上,必须转化为仿真软件可用的谱线。文中详细介绍了传统的正弦加随机谱线转化为窄带加宽带谱线的方法及其转化公式,并提出了2种新的谱线转化方法,即分离为纯正弦谱线和纯随机谱线的方法,以及基于振动试验的一种新的转化为窄带加宽带谱线方法,最后以某PCB板组件为例在NX Nastran中进行了对比仿真分析。结果表明,3种转化方法中基于试验的转化方法最为严酷,分离为纯正弦与纯随机方法次之,传统的转化方法响应最小。

The sine-on-random （SOR）vibration spectrum of helicopter platform can＇t be directly applied to the finite element model . This paper introduces the traditional method and must be translated into the spectrum available for the simulation software, converting SOR spectrum to Random-on-Random （ROR） spectrum and the formula, and proposes two new conversion methods, converting SOR to ROR spectrum based on vibration testing, and converting SOR to pure sine and random spectrum separately. Finally a PCB assembly as an exam- ple are analyzed using the three methods in NX Nastran, the results show that the method converting to ROR spectrum based on vibration testing is the most severe, followed by converting to pure sine and random spec- trum, the traditional method is the most easilv.