Experimental measurements of dynamic response characteristics of a horizontal circular cylindrical shell in contact with fluid

Abstract

Thin-walled curved shells and plates are frequently used in naval architecture and offshore engineering as structural elements. Therefore, it is important to have an accurate understanding of the dynamic characteristics (natural frequencies, mode shapes, etc.) of these structures in contact with fluid. Presence of a heavy fluid significantly alters the dynamic characteristics of the structure, and the natural frequencies of the structure in contact with fluid are significantly reduced compared to those in air. In this study, natural frequencies and corresponding mode shapes of a horizontal cylindrical shell sealed by thin circular plates at both ends are experimentally investigated both in air and in contact with fluid (fully and half-filled cylindrical shell). In the experiments, the cylindrical shell is horizontally connected to a supporting structure at both ends by elastic springs. Modal testing procedures are applied, and the elastic structure is excited impulsively on predetermined excitation points by an instrumented hammer while an accelometer is attached at a predetermined position during the tests. The frequency response functions (FRF) for each excitation point is obtained by PULSE LabShop software. For each test case, the corresponding dynamic properties were obtained by a commercial finite element program, ANSYS, as well. It is observed that the experimentally obtained dry and wet natural frequencies and corresponding mode shapes are in good agreement with the finite element calculations.

More information

Identifiers

ORCID for Ibrahim, Tugrul Ardic: orcid.org/0000-0001-9458-9837

Catalogue record

Export record