Layout optimization of constrained damping material for Composite fan blade

Compared with traditional titanium alloy fan blade, carbon fiber composite blade has the characteristics of high specific strength, strong designability and fatigue damage tolerance. However, the interlaminar properties of composite material are poor, and the resistance to delamination and impact is weak. To effectively reduce vibration stress of structure and to extremely improve the service life, reasonable layout of constrained layer damping (CLD) material is designed. In this paper, a layout optimization method of CLD material for composite fan blades is proposed. By shell element normal stretching, a refine finite element model containing ply information is established. The dynamic mechanical parameters of viscoelastic materials are measured by dynamic mechanical analysis (DMA) test, and then finite element dynamic model of viscoelastic damping composite structure is established. macro fiber composite (MFC) is used to verify the vibration characteristics of the optimized viscoelastic damping composite structure. By comparing optimal layout of CLD material and blade mode of vibration, it is found reasonable laying of CLD can significantly reduce blade natural frequency, reduce blade vibration response, optimize damping ratio, and improve stress-strain distribution.