Numerical Simulation Study Of Damping Property Of Hybird Fiber Reinforced Resin Composites Apllied For Propeller

In recent years,composite materials have been widely used in the field of ships due to their advantages.Composite propeller is a typical application of composite materials in the field of ships.When working underwater,pulsating pressure will be generated on the surface of propeller blade,and will cause the blade vibration to radiate noises.Compared with traditional metal propeller,composite propeller has excellent damping performance.However,with the development of detection technology and the improvement of military forces of various countries,the damping performance of CF/EP composite propellers cannot meet the requirement of ships' invisibility.Therefore,it is a great significance to improve the concealment of ships and to design low-vibration and low-noise propellers to improve the damping performance of composite propellers by means of fiber mixing.By using experiment combined with finite element method(FEM),damping properties of hybrid fiber composite material was calculated on account of the measurement of damping performance of single fiber composite materials.Then by using the method of computational fluid dynamics(CFD)and finite element method(FEM),the combination of hybrid fiber composite propeller hydrodynamic characteristics and mechanical properties of the blade were analyzed.Finally,the amplitude of propeller tip of hybrid fiber composite was calculated and analyzed to verify the effect of vibration and noise reduction,main research content is as follows:Firstly,the damping properties and mechanical properties of three unidirectional fiber composites with single reinforcement were measured,and the influence of the included fiber Angle on the damping properties of the composites was calculated,and the relationship between the damping properties and the included fiber Angle was analyzed.The damping properties of composite materials with different layering hybrid and different fiber hybrid were studied,and the hybrid fiber system were determined as CF/CF/GF,CF/CF/KF,CF/KF/GF,and lamination structure of composite propeller were determined as [±60/±30/0].Secondly,CFD method was used to calculate the hydrodynamic performance of propeller by using RNG k-e turbulence model,and the surface pressure distribution,profile pressure field,velocity field and propeller trace were studied.Using the conclusion of hydrodynamic performance calculation and FEM method,the force analysis of three kind of hybrid fiber composite propellers under the design speed coefficient was carried out,and the hybrid fiber system meeting the mechanical performance requirements of propellers was screened out.All of the three kind of hybrid fiber systems can meet the strength requirementsFinally combining method of CFD and FRM,fluid-structure coupling calculation of CF/EP hybrid fiber composite materials and other two kinds of propeller which meet requirements of the mechanical performance was finished under the same condition.Then the amplitude of the propeller tip compared with the pure CF composite propeller was extracted,and it was found that amplitude at the tip of CF/KF/GF hybrid fiber propeller have the greatest attenuation compared with CF single fiber attenuation of propeller,and the value can reach to-4.085 dB.