Masters Theses


"In this thesis the design of the major components of a torsional vibration machine is presented. The machine is a torsional vibration actuator which will deliver a mean output angular velocity with a superimposed harmonic component. This type of motion can be used to study the torsional vibration characteristics of models representing crankshafts, gear trains, torsional dampers, and other systems. The primary machine elements of the actuator are a power source, flywheel, and a Hooke's joint. The power source consists of a D.C. shunt motor and a drive transmission using 3 V-belts. Through the use of a Hooke's joint, approximate sinusoidal angular velocity variations superimposed upon a mean angular velocity are generated at the output shaft. The effects of the variations in the output shaft speed upon that of the input shaft are minimized by the use of a flywheel. This is essential to generate nearly sinusoidal variations in the output shaft speed. The flywheel design is such that its inertia can be changed in steps by addition or subtraction of segments to a disc flywheel. Specimens to be tested with the motion generated are rigidly connected to the output shaft of the Hooke's joint. The frequency of the sinusoidal input motion to the specimen is varied by changing the input shaft speed of the Hooke's joint. By using a D.C. shunt motor with field control equipment, the input shaft speed can be adjusted to any desired speed within the range 370-1000 RPM. As the frequency of variation of the output shaft is nearly a second harmonic of the input shaft speed, the corresponding range of frequency of variation at the specimen is 12-33 cps. The amplitude of variation at the specimen is established by changing the angle between the input and output shafts of the Hooke's joint. This angle is limited to ±20º, as beyond this angle the variations in the output shaft velocity do not closely approximate sinusoidal conditions. The amplitude of the mean output velocity is controlled by the input velocity. The machine vibrations within the actuator system are isolated from the supporting structure by placing the machine on isomode vibration pads. The isolation system is designed such that the ratio of the lowest forcing frequency during testing and the fundamental frequency of the rubber pad-machine system is greater than 1.4, i.e., the transmissibility is less than one"--Abstract, pages ii-iii.


Rocke, R. D. (Richard Dale), 1938-

Committee Member(s)

Gatley, William S.
Hornsey, Edward


Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering


University of Missouri--Rolla

Publication Date



x, 104 pages


© 1972 Prafulchandra Pragjibhai Desai, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Rotors -- Vibration -- Design and construction
Actuators -- Design and construction
Universal joints -- Vibration -- Mathematical models

Thesis Number

T 2693

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