Ryan Neward


Serpentine belt drive systems are widely used in automobiles due to their compactness and long life. These systems are composed of a belt, a driving pulley, driven pulleys, and a spring-loaded tensioner. The driven pulleys may include such accessories as the alternator, air conditioner, or power steering pump. Serpentine belt drives experience many different types of steady state motions and transient vibrations due to the different parameters in the system. As a result of this, it is important to create a mathematical model that allows the designer to extract information about the system such as the natural frequency and the mode shapes. The accuracy of the model will depend primarily on the assumptions used. In particular, a key assumption is whether transverse and rotational motions of the belt are coupled due to the motion of the automatic belt tensioner. This coupling is often neglected by authors who model only longitudinal belt response and in effect decouple the transverse and rotational motions. Using a solution based upon coupled motion as well as a solution employing rotational motion only, the importance of this coupling will be assessed. Both solution results will be compared against published experimental data. In addition, a parametric study will be performed to determine the ability of the coupled and decoupled models to accurately predict changes in system natural frequencies and mode shapes due to changes in system parameters.

Library of Congress Subject Headings

Belt drives--Mathematical models; Couplings--Mathematical models

Publication Date


Document Type


Student Type


Degree Name

Mechanical Engineering (MS)

Department, Program, or Center

Mechanical Engineering (KGCOE)


Stephen Boedo

Advisor/Committee Member

Agamemnon Crassidis

Advisor/Committee Member

Kevin Kochersberger


Physical copy available from RIT's Wallace Library at TJ1100 .N49 2006


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