Research On Vibration Characteristics Of The Grid Structure Based On Asymptotic Homogenization Method

Grid structure is a new and efficient structure with many potential advantages,which has a good application foreground in the fields of aviation and aerospace.This paper studies the vibration characteristics of periodic grid structure based on the asymptotic homogenization method.This paper mainly makes the following three areas of research for grid structure:(1)Based on the asymptotic homogenization(AH)theory of periodic structures,an improved implementation technique of AH is developed to solve the effective properties rapidly and accurately with the aid of commercial finite element method(FEM)software as a tool box.A comparison of several methods reveals that this implementation method is simple and the result obtained is accurate.Applications to the predication of macroscopic elastic constants of long fiber reinforced composite are presented.(2)Based on the AH method of periodic plate structure and classical shell theory,a method for predicting the equivalent shear stiffness of grid structural plate is developed.Then an integrated unit cell model of grid structure is established to calculate the equivalent stiffness.A vibration analysis result of equivalent model verifies the high efficiency and accuracy compared with the result of the FEM refined model.The correctness of the equivalent model is validated by modal experiment of grid structure consisting of aluminum honeycomb and face plate.Effects of the design parameters on the vibration performance of grid structure are discussed.(3)An integrated unit cell model with triangle grid structure is established and its mechanical properties are calculated.The vibration modal parameters of an engine case constrained by a fixed end and a free end are analyzed and research on effects of the design parameters on the frequency of the case is carried out.The conclusion has a particularly important practical value in dynamic design of the engine case with triangle grid structure.