摘要
结合FPK方程和非线性等效原理,对随机激励下的分别含有非线性阻尼、非线性刚度的单自由度系统计算等效阻尼及等效刚度。结果表明:非线性系统的等效线性频响函数图及奈奎斯特图随外激励量级的变化而变化,不同非线性类型的等效频响函数及奈奎斯特图随外激励量级的变化规律不同,从而给出了对根据实测频响函数与奈奎斯特图变化规律定性分析振动系统非线性特性和软硬特性的方法,为真实非线性动力学系统建模提供了理论依据。最后应用此方法对铝蜂窝夹层板的随机试验数据进行定性分析,得到结果可用于指导建模。
Under random excitation, the behavior of SDOF nonlinear system is investigated. Nonlinear damping and nonlinear siffness are considered respectively. Equivalent linear damping and equivalent linear stiffness of nonlinear system are caculated by combining FPK transform and equivalent principle method. Results of equivalent linear FRF （Frequency Response Function） and Nyquist show that the FRF and Nyquist will change with the variation of excitation level. Moreover, it is observed that different nonlinear type shows different features. Thus the type of nonlinear can be charactered, and the hardening or softening characrteristic of the system can be deduced too.The result provides a theoretical foundation for choosing the model of the nonlinear dynamic system. The method can be used to identify the random test data of an aluminum honeycomb sandwich board to character the the type of nonlinear.
出处
《工程力学》
EI
CSCD
北大核心
2010年第4期24-29,共6页
Engineering Mechanics
基金
863计划项目(2007AA702202)
