General causes and consequences of torsional vibrations.

write a short article (no more than 2,500 words) to discuss problems
associated with torsional vibration in ship propulsion systems. The areas that should be
covered in this coursework include:
• General causes and consequences of torsional vibrations.
School of Engineering
• Possible ways of treating the torsional vibration problems in both design and operation.
• Recent developments in this research area over the past 10 years.
You are encouraged to find information in your literature search from sources such as Web
of Science/Knowledge (SCI database), Internet, etc. Please note that you cannot produce this
coursework solely based on data and information obtained from Internet sources. Attention
is suggested to be paid to the structure of your written article, appropriate use of references,
your own analysis based on the literature search, and effective use of diagrams, tables and
bullet points where appropriate.
Part 2
A simplified ship propulsion plant is, as far as torsional vibrations are concerned, reduced to
a system of the form shown in Figure 1. The moments of inertia of the 9 rotors are given as
follows:
J1 = J9 = 4.0 kg m2
J2 = J3 = J4 = J5 = J6 = J7 = 0.4 kg m2
J8 = 2.0 kg m2
The values of shaft stiffness are as follows:
K1 = 1.0×107 Nm/rad.
K2 = K3 = K4 = K5 = K6 = 1.4×107 Nm/rad
K7 = K8 = 2.0×107 Nm/rad
i. Show that there is a natural frequency of the system between 8000 and 8500
vib/min.
ii. Given that the frequency between 8000 and 8500 vib/min is either one node or
two node, determine the node of this natural frequency.
iii. Find the natural frequency falling within the range of 8000 to 8500 vib/min.
iv. Draw and also interpret the elastic curve at this obtained natural frequency.