Acoustic Fatigue Research For Honeycomb Sandwich Structure Based On Power Spectral Density Method

Honeycomb sandwich structure is widely used in aircraft wing leading edge,rudder surface,engine fairing,etc.So it is susceptible to strong aerodynamic noise.In order to analyze the acoustic fatigue of honeycomb sandwich structure,the Power Spectral Density(PSD)Method combined with P-M linear cumulative damage theory,S-N curve and probability density function is used to calculate the acoustic fatigue life of the structure.The research contents of this article are as follows:1.The effect of temperature on the properties of materials is added,the acoustic fatigue life of the engine’s acoustic lining structure is calculated under different sound load and different temperature;2.The core of honeycomb sandwich structure is equivalent to solid structure by Meso-Finite Element Method.The result shows that: the stiffness of the structure will be increased by using the equivalent structure,a huge difference in acoustic fatigue life exist between equivalent structure and non-equivalent structure if the size of the structure is small.Because the influence of the boundary conditions and detail structures.3.The vibro-acoustic coupling method has been used in the non-equivalent structure in order to analyze the influence of different diameter holes in the upper panel of the honeycomb sandwich structure on the acoustic fatigue life.The result shows that: the acoustic wave is affected by the viscosity when it propagates in the opening structure,and heat loss occurs during the propagation,which can absorb part of the acoustic energy and reduce noise.Therefore,the small open-cell structure has a positive effect on the acoustic fatigue life.4.Complex damages may generate if the panel of honeycomb sandwich structure which made by composite material under low velocity impact,such as fiber breakage,matrix fracture and delamination.The acoustic-vibration coupling fatigue life of the structure is calculated on the basis of the structure containing damage,material stiffness degradation,and deformation.The results show that when the impact energy is small,the effect on the acoustic fatigue life of the structure is extremely low;but when the energy exceeds a threshold value,the acoustic fatigue life of the structure shows a cliff-like decline.