摘要
本文针对一种“从自由结构试验提取约束结构试验模态的动柔度法” ,在遇到ω≈λh ,s和ω >λh ,k+ 1两特殊情况下将无效的问题 ,提出了有效的对策。这种“对策”就是作者曾提出的“混合移频”技术辅以“逐个移频”步骤。最终发现 ,不仅对于两种“特殊情况” ,本文方法是行之有效的 ,就是对于“一般情况” 。
Under the certain prerequisite the dynamic flexibility method for extracting constrained structural modes from free test data will be invalid when both`ω striding into Λ h'and `ω≈λ h,k+1 or ω≈λ h,s 'situations happen.The former means that test frequency range of constrained structure is larger than that of free structure,that is,the some frequencies ω of constrained structure is larger than most small frequency λ h,k+1 in the higher order analytical frequencies of free structure.λ h,s in the latter is any value in the higher order analytical frequencies of free structure.Under two such situctions,a power series existing in the dynamic flexibility method diverges,which leads the method to be invalid .For solving these problems,an improvement of the dynamic flexibility method above mentioned is proposed in this paper.The kernel technique of this improvement is a `hybrid shifting frequency'procedure developed by the author.Finally form the numerical results,it is found that the improved method shown in this paper not only is valid for two stated particular situations,but also is better than the original dynamic flexibility method for the general situation.
出处
《强度与环境》
2002年第2期10-17,共8页
Structure & Environment Engineering
