Dynamic Structural Analysis With Experimental Verification

Abstract

There are basically two methods of determining the dynamic response of structures. Analytical methods take advantage of theoretical equations to predict a system's response, while experimental methods use testing of prototypes or scale models of a structure to determine actual response. In order to design structures efficiently, an engineer should be able to use theoretical tools to analyze and predict a system's response. This research project was designed to predict the accuracy of modeling structures subjected to dynamic loading using the finite element method. A finite element computer program was written and used to analyze two structures-a simple cantilevered beam and a cantilevered beam with another beam welded to it at a 90° angle. The structures that were modeled by the program were then constructed and tested using modal analysis techniques. The finite element model and experimental results were then compared to see how accurately the model predicted actual system response. The results of this research showed that the finite element model was able to predict actual system behavior with a high degree of accuracy. The analytical model was able to predict natural frequencies and mode shapes within 19.1% of the experimentally-determined values for the cantilevered beam, and within 6.1% of the experimentally-determined values for the welded beams.