多自由度模型NOFRFs估计及损伤检测的数值模拟

Damage Detection Simulation and Estimation of NOFRFs on Multi-Degree Freedom Model

基于Volterra级数理论定义的NOFRFs相当于非线性系统中的"传递函数",可很好的表征非线性系统的本质特性,是非线性检测的重要工具。结合NOFRFs的一般估算理论,考察了脉冲锤击信号的特点,进而推导了脉冲锤击激励下NOFRFs的估算方法。对一维八自由度模型的数值模拟分析,验证了该估算方法的有效性,此外,还利用前人构建的NOFRFs指标实现了对该模型系统非线性特性的检测。

The NOFRFs defined by the Volterra series behave as the transfer function of nonlinear systems and can represent the nature of nonlinear systems. The NOFRFs theory provides an important tool for nonlinear detection.Based on the general estimation theory of NOFRFs and the characteristics of impulse hammer excitation,a new estimation method of NOFRFs under impulse hammer excitation came up. The numerical simulation analysis on the eight-degree freedom model demonstrates the effectiveness of the new estimation method. Besides,the nonlinear detection for the foregoing model is realized using the NOFRFs index put forward by the predecessors’.