悬臂梁弯曲共振法自由阻尼结构试件设计研究

Study of the Design of Free-damping Form Specimen in Resonance Method

用悬臂梁弯曲共振法测量阻尼材料动态力学参数时,试件设计是否合理直接决定了测量结果的可信度。考虑到复合试件基底层材料阻尼的影响,本文对测量理论进行了改进,得到了考虑基底层阻尼影响的悬臂梁弯曲共振法测量方程。仿真结果表明忽略基底层阻尼将会导致杨氏模量和损耗因子测量精度降低,并且损耗因子测量误差对基底层阻尼变化更敏感。这为基底材料的选用提供了一定的理论依据。本文还结合误差放大因子的概念,对试件设计若干关键参数进行了灵敏度分析,得到了一组对悬臂梁弯曲共振法自由阻尼结构试件设计具有指导意义的结论。

In the measurement of damping material＇s dynamic mechanical performance using flexural resonating cantilever beam method （＂resonance method＂ for short）, appropriate design of specimen will decide the result＇s reliability. Taking into account the base beam damping effect, this paper has improved current measurement theory and presents a measurement equation based on flexural resonating cantilever beam method. Simulation results show that ignoring the base beam damping effect will result in obvious errors to the Young ＇s Modulus and loss factor, moreover, the measurement errors of loss factor are more sensitive to the change of base beam damping. This supplies a theoretical gist for the base beam material selection. In addition, the measurement error sensitivity of several key specimen parameters in free-damping form was analysed based on the erroramplify factor method, and some helpful advices for specimen design were obtained.