纤维增强树脂基复合材料水翼阻尼特性研究

Study on Damping Characteristics of Fiber Reinforced Resin Composite Hydrofoils

针对不同铺层工况下复合材料水翼的结构阻尼和水力阻尼进行研究和分析,以NACA0009复合材料梯形水翼为模型,建立了复合材料水翼结构阻尼和水力阻尼计算方法。基于模态应变能法的结构阻尼计算方法研究了不同纤维的铺层角度、阻尼层分布位置、阻尼层厚度及纤维厚度等对复合材料水翼结构阻尼的影响规律。结果表明:0°铺层阻尼损耗因子小于+30°和-30°铺层;随着阻尼层离中心层的距离增大,阻尼层受到的约束逐渐增强,阻尼损耗因子因此增加;单层阻尼层厚度和纤维厚度对阻尼损耗因子的影响不大。基于复合材料水翼模态特性分析表明,复合材料铺层角影响水翼的模态振型和频率,相比于0°铺层,+30°和-30°铺层水翼的一阶模态频率降低,二、三阶模态频率升高。模态频率越大,对应的模态阻尼比越小。同时,研究了不同铺层水翼的水力阻尼,相比于0°铺层,+30°和-30°铺层水翼的水力阻尼比更大。该成果为复合材料螺旋桨减振降噪结构设计提供指导。

Structural damping and hydrodynamic damping of composite NACA0009 trapezoidal hydrofoil under different layup methods were studied and analyzed.The calculation methods of damping and hydraulic damping of composite hydrofoil structures were established.The structural damping calculation method based on the modal strain energy method was used to study the influence of different fiber laying-angle,damping layer distribution positions,damping layer thicknessand fiber thickness on the damping of composite hydrofoil structure.The results show that the damping loss factor of the composite hydrofoil with the fiber orientation angle of 0°is smaller than those of+30°and-30°.As the distance between the damping layer and the center layer increases,the constraint on the damping layer increases gradually,and the damping loss factor increases.The thickness of a single damping layer and fiber thicknesshave little effect on the damping loss factor.Based on the analysis of modal characteristics of composite hydrofoil,the result shows that the composite layup angle affects the mode shape and frequency.Compared with the layup angle of 0°,the first mode frequency of the composite hydrofoil with the layup angle of+30°and-30°decreases,while the second and third modes increase.The higher the modal frequency,the smaller the corresponding modal damping ratio.At the same time,the hydraulic damping of composite hydrofoil is studied.Compared with the layup angle of 0°,the hydrodynamic damping ratio of the composite hydrofoil with the layup angle of+30°and-30°is larger.This achievement provides guidance for the structural design of vibration and noise reductionofcompositepropeller.