Abstract:
Rotating machinery systems, such as marine propeller shafts or gears, face a vibration
problem, which occurs from bending and torsional modes. Generally, a passive vibration
absorber is used by applying auxiliary mass and a spring device to the primary system. This
device generates the same natural frequency as the frequency of a system or structure.
This thesis uses modal analysis in order to determine the frequency response of a primary
system in terms of transfer function, natural frequency and mode shape . It will compare
the result before and after implementing the device. The Lagrange method is used to
construct an equation of interaction between coupled bending and torsional vibrations. The
natural frequency and mode shape are determined by using MATLAB .The results show
that the vibration of the primary system that results from the bending and torsional mode
at the same time can be reduced. The initial frequency of each mode is separated, therefore
becoming two frequencies . All results from 3 cases agree with the results from the finite
element method