Vibration and Damping of Thin-Walled Cylinders

Author: Watts, George Arthur

Year: 1962

Degree: Engineer's thesis

Advisor: Fung, Yuan-cheng

Committee Member: Unknown, Unknown

Option: Aeronautics

DOI: 10.7907/XPER-7Q77

Abstract

The frequencies of normal modes of free vibration of three cylinders of different thickness were found experimentally. For some of the modes damping was also found. The modes excited were of a single axial half wave and multiple circumferential waves.

The shells were geometrically similar except for thickness and were made by electroplating copper on accurately machined wax mandrels. Melting the wax produced shells of very uniform thickness without seams.

The modes and frequencies agreed to within 10% of the theoretical values for cylinders with fixed ends, except at small numbers of waves where they agreed more closely with the theoretical values for freely supported ends. The damping factors tended toward a small constant value with increasing numbers of waves above the mode with fundamental frequency, but increased rapidly as the numbers of waves decreased below the fundamental.

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