Study On Damage Detection Of Honeycomb Sandwich Plate With Low Velocity Impact Damage

As a special kind of composite structure, the honeycomb sandwich structure with predominant performance of low density, high intensity and high stiffness ratio, is applied widely in aerospace field. For the honeycomb sandwich panel has characteristics of complex structure.long development cycle, multifarious production procedures, light weight and high strength, it is easy for kinds of macroscopic imperceptible damage to appear in it in the process of research, assembly and transport. Shock damage has been considered as one of the most important form of damage in the composite structures. Shock damage destroys the honeycomb sandwich structure’s integrity, and makes its compression strength, bending strength and bending stiffness drop significantly, prone to sudden accidents. At present, most scholars study composite material panel mostly limited to its dynamic response, but hardly obtain any accurate complete results of damage judgment. As the damage identification of the honeycomb sandwich panel is so important to engineering, it is a research topic of great significance in composite materials area to make out the correct diagnosis of the existence of damage in honeycomb sandwich structure, the location of the damage and the degree of the damage.In this paper, the research object is an aluminum simply supported honeycomb sandwich panel with small impact damage, and the damage identification problem of the honeycomb sandwich panel is studied. The main research contents of the paper are as following.Based on knowledge of damage mechanics, the degree of the damage is characterized in the form of the damage factor, the structure mechanics parameters are corrected by changing the damage factor, and the theory of third-order shear deformation panel is applied to deduce the frequency equation of honeycomb sandwich panel with damage. Then the modes of honeycomb sandwich panel can be obtained after obtaining the frequency. Based on the summary of several main methods of structural damage identification, the modal experiment of the simply supported honeycomb sandwich panel is carried out. An INV3018C intelligent signal acquisition and processing analyzer of is used in the experiment. The natural frequency and modal data of the honeycomb sandwich panel with or without damage is accurately collected through Coinv DASP V10modal and dynamic analysis software.Based on damage identification through the frequency, the frequency method, the frequency fingerprinting method and anti-resonance frequency method are adopted; based on damage identification through the modes, the modal difference method, the curvature mode method and the Gaussian curvature mode state law are adopted. Finally, the identification of the damage, determination of the damage location, and estimation of the degree of the damage are obtained correctly in the simply supported honeycomb sandwich panel.