Many industrial structures are usually constructed with frame-type system to support industrial facilities such as vibrating machines. The vibrating machines having various vibration modes are installed on the beam of the industrial structures. The vibrations of machines mostly consist of vertical vibration component.
In case of modal analysis method for vertical vibration analysis of the industrial structure, higher mode vibration effects are predominant. These higher mode vibration effects must be considered. In these cases, vibration of beam is important, so beam must be devided in many elements for accurate behavior. This division of beam elements results in large size of degree-of-freedom. Therefore it is contacted with increasing of computation time in eigenvalue problem and time history analysis.
In this paper, three methods are presented to reduced these difficulties. The first method is to determine minimum nodes that shall be used to obtain dynamic response with the vertical vibration. Secondly, matrix condensation methods are introduced to reduce the computation efforts used to perform dynamic analysis and the selection of master degree-of-freedom is proposed. The third method is of using the sub-structuring technique for local vertical vibration analysis. The boundary conditions used to this technique is determined by using matrix condensation.
Finally, above mentioned methods are shown to be efficient in numerical analysis results of the example structures. The accuracy of presented methods is compared with the results of numerical analysis and experimental results of one bay-three story steel frame.
