Research On Coupling Loss Factors Of Aluminum Honeycomb Sandwich Plates

Statistical Energy Analysis(SEA) is an very effective method for the solution ofhigh-frequency dynamics problem of the complex structure, which is widely used in thefields of aerospace and aviation. It is the key to solve project practical problemsuccessfully using the SEA that SEA analysis parameters can be estimately correctly.Aluminum honeycomb sandwich plate is widely used as the main bearing structures onspacecrafts due to its properties like lightweight, high strength and high stiffness, goodstability. However, Aluminum honeycomb sandwich plate is an anisotropic plate，Whichis hard to estimate the CLF between Aluminum honeycomb sandwich plates by theorymethod. To solve this problem, Based on the model method and Dual Formulation, anew method for identifying the CLF between Aluminum honeycomb sandwich plates isproposed. The specific research contents of this dissertation are as fellow:The basic principles, assumes and range of application of SEA are analysedsystematically, the classic SEA paremeters identification method and an experimentalmethod(Power input method) are disscused. On this basis, an formula which is calculatethe modal coupling coefficient directly by the vibrate modal information of couplingboundary are deduced, after interaction modal work for discretized sysytem. A methodwhich can be used to estimated the CLF of honeycomb sandwich plate and shell systemby using the force variables and displacement variables of nodes on coupling boundaryis proposed.A case of two-coulped aluminum honeycomb sandwich plates in an L shape iscondidered, and the CLF of this model is estimated by Dual Formulation Method withFEM (DFM/FEM). the case have verified the validity of determination with DFM/FEMafter compared to the results yielded by the SEA numerical experiment and SEAsoftwave VA-one. The results show that, DFM/FEM is more simple, light computationaland good precision. Than, the influence of thichness and damping to the estimate ofDFM/FEM is disscused. results show that high precision values are estimated byDFM/FEM when thickness of two plates is different, some slight errors are noted foraluminum honeycomb sandwich plates of equal thickness. CLF values estimated byDFM depend slightly on damping with damping values small relative to couplingfactors. And than, the case of coulped aluminum honeycomb sandwich plate and shellsystem is researched, which is verified the validity of DFM/FEM in complex structures.A vibration experiment on the two L-shaped coupled aluminum honeycombsandwich plates has been carried out, verifies the validity of using dual formulationmethod to estimate the CLF of aluminum honeycomb sandwich plates system. Experimental scheme is designed according to the experimental goal. The input powerto the test plates and its vibration energy are obtained from measured data, which can beused by power input method to indentify the CLF of test structure. Compare the theexperimental result to the DFM/FEM result, the two result are in agreement obviously,which further verify the correctness of the method as well.