从自由试验提取边界具有弹性支承的约束结构模态

作者曾对“从自由试验提取约束结构模态”所提出的动柔度法,仅适用于刚性支承情况。在工程中,弹性支承状态是常见的,为此,本文重新建立了这一情况下,约束结构试验模态的提取方法。该方法具有普遍性,因为当支承刚度很大时,由本文方法可得到刚性支承下的结果;当支承刚度很小时,便可获得工程中用橡皮绳悬吊结构后所测得的自由－自由试验模态;当支承刚度为零时,本方法可提取到纯粹的自由－自由模态。总之,当支承刚度为任何值时,本方法都能提取到相应约束结构的满意试验模态参数。这些表明本文算法是非常的稳定,这一点对于工程应用是至关重要的。

Transforming Free-Free Modes to Constrained Modes for a Structure with Elastic Supporting

The author proposed a dynamic flexibility(DF)method and an improved DF method for extracting constrained structural modes from free test.These methods are only suittable to the structures with rigid supporting.However the structures with elastic supporting exist widely.For this reason,a more general method for extracting modes of constrained structure with elastic supporting from free test is developed in this paper.So called general method means four respects:(i)when stiffness of the supporting is very large,the method shown in this paper can give the experimental modes of constrained structure with rigid supporting ;(ii)when stiffness of the supproting is quite small,free free test modes in the engineering can be obtained,in which the structure is suspended by using rubber rope etc;(iii)when supporting stiffness is zero,the pure free free experimental modes can be found by using the present method;(iv)when supporting stiffness is arbitrary values,the method can give all the satisfied results.These show that the algorithm shown in this paper is considerably stable.This is fairly important for applications of the method to engineering.