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

The sine-on-random(SOR)vibration spectrum of helicopter platform can忆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 example 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 spectrum, the traditional method is the most easily.