Random Vibration Analysis Of The Rocket Instrument Cabinet Based On The Pseudo-excitation Method

The launch vehicle is usually suffered random excitations from the propulsion system of the engine and the turbulent flow. With the rapid development of aerospace technology, random vibration analysis of launch vehicles under random excitations has received more and more attention. For the low efficiency of the traditional CQC method, it is always difficult to meet the needs for the precise random vibration analysis of the launch vehicle. In this paper, based on the principle of pseudo-excitation method, the harmonic response analysis module of general finite element software ANSYS and ABAQUS is used to make PEM realizable on large complex structure. And then this kind of method is used to calculate the response of the rocket instrument cabinet under uniform foundation acceleration excitation. Three parts are consisted in this paper as follows:Firstly, traditional CQC method and PEM in complex field are introduced. A new formulation of PEM subjected to uniform stationary ground acceleration excitation is derived. This form of PEM can be directly fulfilled in the harmonic response analysis module of general FE software such as ANSYS, ABAQUS, etc.Secondly, a transmission tower under uniform random ground acceleration excitation was considered as an example. The harmonic response analysis module of the FE software ANSYS is then used to calculate the pseudo-responses of the transmission tower. The results obtained by this method were then verified in comparison with those of the traditional PEM and PSD analysis of the FE software ABAQUS.Finally, the methods mentioned above were applied to the numerical simulation of the rocket instrument cabinet. Based on PEM in real field, using harmonic response analysis module in the FE software ABAQUS, random vibration analysis has been made for the response of the rocket instrument cabinet under uniform random ground acceleration excitation. And the results were justified in comparison with the PSD analysis of the FE software ABAQUS. The results suggested that the realization of PEM using general finite element software were precise and effective in the analysis of complex structures.