Experimental Modal Analysis Of Beam-column Joint Rotation Of Steel Frame Structure

With the rapid development of various trades and industries, as an interdisciplinary, modal analysis technique has been developed rapidly. It has a very wide range of applications in aviation, aerospace, automotive, machine tool, the vibration characteristics of power generation equipment, bridges and hydraulic structures analysis, vibration control, fault diagnosis and prediction, and noise control, and so on.In conventional experimental modal analysis, we attach more importance to the study of mode rotation. Usually, in the study of the structural mode shape, we take more consideration in modal frequencies and modal displacement. In fact, modal rotation is important to the research of the mode shape, and it has a very wide application in structural engineering. Therefore, the main content of this paper is to obtain the mode rotation by experimental modal analysis.In this paper, we firstly got the mode shape of the frame structures through the test modal analysis technique. The framework used in the experiment was made of prefabricated splicing, the beam-to-column joint is connected by bolt,in this way, it was easy for us to assembly and disassembly test model. The equipment of the experiment was DH-5922 dynamic signal analyzer, in the experiment, the acceleration sensor was arranged in the measuring point of the framework, then we knocked at framework with a hammer, in order to get the frequency response between excitation and acceleration, after that, the frequency response analysis results were obtained for processing, and we got the modal of the framework. Secondly, according to the displacement mode of beam and column units, we can realize the curve fitting of the beam and column, then we put the modal displacements of the measured point into the formula to calculate the beam-to-column joint mode rotation. Thirdly, we used the finite element software ABAQUS to build the modeling of the framework and to get the theoretical value of the modal rotation, then we compared the both results, in order to verify the accuracy and validity of the test results. At the end of this article, the deficiencies of the proposed method were analyzed and the next step of the research work was carried out.