Modal analysis of missile's equivalent density finite element model

For investigating the structural vibration of slender missile, the simplified analysis model needs to be established to analyze structural dynamics characteristics of slender missile containing many non-structural masses. Considering shortcomings of past methods that non-structural mass was equivalent to 0-D point element or 3-D solid element, the method of equivalent density was proposed, namely, according to equivalence theory of density and stiffness, non-structural mass was distributed to the shell elements, and corresponding material density of shell was modified to ensure mass invariable. The finite element models were respectively established by the three methods, modal test of missile model was accomplished. The comparisons of modal frequencies between experimental and calculating values show that the model established by equivalent density method is more reasonable and easy to use.