基于Prony法的非线性阻尼辨识与实验研究

针对合金材料的非线性阻尼性质,在扩展的Prony法的基础上提出了从自由响应信号中辨识非线性阻尼的移动Prony法和时变Prony法.通过对不同特性的阻尼进行仿真和分析,证明了这两种算法的有效性,同时得出了时变Prony法更适用于非线性阻尼的辨识的结论.在传统阻尼实验装置的基础上,开发了具有准均匀应力场的梯形等强度梁试件.实验结果表明所研究的阻尼合金Al-33Zn-6Si的阻尼能力随着应变的增加而增加,呈现明显的非线性关系.

STUDY ON IDENTIFICATION AND TEST OF NONLINEAR DAMPING BASED ON PRONY METHOD

According to nonlinear damping characteristics of an alloy,the moving Prony and the time-varying Prony methods based on the Prony method are put forward to identify the nonlinear damping of the alloy from its free response signal.The effectiveness of these two methods are illustrated through simulation and analysis of the damping with different properties.Furthermore,it is demonstrated that the time-varying Prony method presented is more effective to identify nonlinear damping than the moving Prony method.A trapezoid specimen with a quasi-uniform stress field is developed on the basis of the traditional damping experimental equipment.It is concluded from the experimental results that the damping capacity of the alloy Al-33Zn-6Si increases with increase in strain.The relation between strain and damping is obviously nonlinear.