Method and system for optimizing finite element model in airborne external store fatigue simulation

The invention relates to a computer system based on a specific calculation model, and discloses a finite element model optimization method and system in airborne external store fatigue simulation, so as to meet the effectiveness and high efficiency of fatigue life prediction of an airborne external store in a random vibration environment. The method comprises the following steps: establishing a first finite element model of an airborne external store, and outputting global stress distribution of each modal in a first modal order range of the corrected first finite element model; modal space coordinates corresponding to all orders of modals in the first modal order range are obtained; calculating a modal transfer factor matrix according to the actual vibration power spectral density input spectrum and the modal space coordinates, and screening out a dominant second modal order range according to the modal transfer factor matrix; performing refined modeling on an area where the maximum value of global stress di