基于单自由度假设的黏弹性阻尼块-叶片的动力学特性分析

Dynamic characteristics of blades with viscoelastic damping blocks based on single degree of freedom model

采用黏弹性阻尼技术抑制叶片振动,对黏弹性阻尼块-叶片进行动力学特性的理论分析,其中黏弹性阻尼材料采用复模量本构方程,将黏弹性阻尼块-叶片简化成单自由度模型,获得了该结构的固有特性和频域下的谐响应。首先,建立叶根部位施加黏弹性阻尼块-叶片的动力学模型,其中黏弹性阻尼块以无质量复刚度弹簧形式引入到单自由度模型中。然后,基于单自由度假设,采用复特征值法对方程进行固有频率、损耗因子和共振响应的求解。最后,针对某叶片实测并进行模型简化,在给定叶片前三阶固有频率的条件下进行解析分析,并与实验结果进行对比。结果表明:黏弹性阻尼可以有效地降低叶片的振动,理论解析结果与测试结果趋势一致,验证了所建模型的适用性。

Theoretical research is conducted on dynamic analysis of vibration suppression of the blade with viscoelastic damping block. Using complex modulus model to represent the constitutive law of viscoelastic material,the blade is simplified to single degree of freedom model, to achieve natural frequencies and harmonic response in the frequency domain. The analytical dynamic model of the blade with a viscoelastic damping block at the root of the blade is established. Viscoelastic damping block in the form of the massless complex stiffness spring is introduced into the system. Subsequently, based on the single degree of freedom model, complex eigenvalue method is adopted to analyze the contributions of natural frequency,loss factor and response on the resonant frequencies and response level. Finally, analytical and test results are compared and mutually confirmed, showing that all the viscoelastic damping served an good role in vibration suppression.