An Experimental and Numerical Investigation of the Vibrational Response of a Flanged Cylinder Structure

Abstract

The paper presents a combined experimental and numerical investigation of the vibrational response of a flanged cylinder structure due to a time-harmonic point excitation. The principle focus of this study was to (1) determine the relative sensitivity of the vibrational response of the cylinder due to variations in the experimental configuration (such as using different vibrational sources, excitation points or complicating structural configurations), and (2) ascertain the level of detail required in the numerical models to accurately replicate the experimental results. Overall, good agreement was achieved between the measured and modelled mode shapes/frequencies up to approximately 1500 Hz, while the experimental results were shown to be largely insensitive to the excitation point or type of mechanical shaker employed. Comparative identification of the measured and modelled cylinder mode shapes allowed for other measured frequency response peaks which did not exhibit discernible modal patterns to be identified from the FEM analysis as either bending modes or internal plate modes for the structure. Finally, it was observed that the contact condition used to model the bolted plates in the structure had a significant effect on the predicted plate modal frequencies, while small amounts of mass loading in the experimental configuration were predicted to cause significant frequency shifts for certain modes.