基于随机振动响应的结构非线性参数识别

复合材料结构呈现出典型的量级非线性特征,非线性刚度的研究是结构设计和分析的基础。结构使用环境多数存在随机振动载荷,在更接近真实使用环境下对非线性参数的识别结果更加适用。文章提出了基于随机减量法和连续小波变换的非线性参数识别方法,设计了基于随机振动响应的非线性刚度识别程序;通过立方刚度单自由度非线性系统算例,验证了识别方法和程序;并通过试验研究了典型复合材料结构的量级非线性特征。结果表明,基于随机减量法和连续小波变换的非线性参数识别方法具有较好的识别精度,多自由度系统不同谐振阶次的非线性特性存在差别。研究结论对于随机振动环境下结构非线性参数识别和建模具有一定的参考价值。

Identification of nonlinear parameters of structure based on random vibration response

The composite material has typical nonlinear characteristics. Its nonlinear stiffness is very important for the system design and analysis. The random vibration is ubiquitous in the environment, and the identification of nonlinear parameters in the practical environment gives more reasonable results. A method of identification of nonlinear parameters based on the random decrement method and the continuous wavelet transform is presented. And a program of identifying the nonlinear stiffness based on the random vibration response is developed. A numerical example of a single freedom nonlinear system with cube stiffness is given to validate the method and the program. The nonlinear characteristics of the typical composite material structure are studied. It is shown that the method of identification of nonlinear parameters enjoys a high precision, and different resonant order of a multi freedom system has different nonlinear characteristics. The present method is useful for the nonlinear parameter identifying and modeling in a random vibration environment.