This document summarizes research on optimizing the design of parallel motion marine fenders. Parallel motion fenders consist of a fender panel supported by arms attached to a torsion tube. The current design fails due to stresses on the torque arm from ship impacts. The researchers modeled an existing parallel motion fender and analyzed stresses from ship impacts at different angles. They then modified the design by adding a gear mechanism to distribute loads and eliminate the torque arm. Analysis of the new design found stresses below allowable limits with a safety factor of 4.42, indicating the gear mechanism achieves the goal of optimizing the parallel motion fender design.

1. IJSRD - International Journal for Scientific Research & Development| Vol. 1, Issue 9, 2013 | ISSN (online): 2321-0613
All rights reserved by www.ijsrd.com 1978
Performance Optimization and Fe Analysis of Marine Fender
Manish G. Dobariya1
Sumant P. Patel2
1
P. G. Student 2
Assistant Professor
1, 2
U. V. Patel, Gujarat, India
Abstract—in port area the problem of handling of large
vessels at river bank is arises from many years. Many
research has been gone throw in this area and one of the
generalize solution has been found by using fender. A
fender is the interface between a ship and the shore
facilities. Generally, its main objective is to protect the
ship’s hull from damage. In some cases it’s the shore
facilities that require protection against impact of the ship,
but the failure of fender is new problem that faces by the
designer because of the heavy impact of the ship. Parallel
motion (PM) fenders are a relatively recent development in
fender technology. This work regarding to the redesigning
of the parallel motion fender that fails under torsion arm and
give the probable solution for remove this problem. For
achieving optimize parallel motion fender there is two
options to achieve the above said goal. One is to add gear
mechanism with damper system and another is to add spring
mass system which increases stiffness of the parallel motion
fender. In gear damper system torque tube will be
eliminated.
Key words: Parallel Motion Fender, Ship, Gear, spring,
Optimization
I. INTRODUCTION
Fendering is basically the interface between a vessel and the
berth facility. This medium serves to absorb a certain
portion of the kinetic energy of a vessel without damage to
the vessel and the waterfront structure. In the case of rubber
fenders, which are generally relatively soft, the majority of
the energy is absorbed through elastic deflection of the
fender. But, possibly also the deflection of the berth facility
and/or the vessel’s hull will contribute to the absorption of
the kinetic energy. On the other hand, when a vessel berths
against a single vertical pile the majority of the energy will
be absorbed by the deflection of the relatively flexible pile.
The deflection multiplied by the reaction force which is
generated and a certain efficiency factor equals the kinetic
energy.
Parallel Motion Fenders were conceived to
overcome the shortcomings of conventional fenders. A
parallel motion fender consists of a fender panel, similar to a
conventional panel but backed by only a single fender unit
(or pair of units mounted together) at its center. To support
the fender panel and to restrain it so that it is always vertical,
it is mounted on a pair of arms which project from a torsion
tube. The connection between the arms and the panel is
hinged and the torsion tube itself is mounted on hinges.
II. PROBLEM DEFINITION
Base on review, there is no work done regarding to failure
of fender. From literature survey, we can say that parallel
motion fender widely used because of its functional and
operational accuracy than other type of fender. But in
conventional parallel motion fender main load bearing
element is torque arm which sustain the entire jerk and
impact load. Due to heavy loading, torque arm often fails.
In this work, our aim is to reduce torque arm
defects and improve the life of parallel motion fender by
implementing new mechanism which can eliminate torque
arm defect.
III. MODEL OF PARALLEL MOTION FENDER
Fig. 1: Model of Parallel Motion Fender
IV. MESHING OF PARALLEL MOTION FENDER
Type of Mesh: - 3D
Type of Element: - Tetrahedral (10 Node)
Number of Nodes: - 157312
Number of Element: - 63037
Fig. 2: Meshing of Parallel Motion Fender

2. Performance Optimization and Fe Analysis of Marine Fender
(IJSRD/Vol. 1/Issue 9/2013/0070)
All rights reserved by www.ijsrd.com 1979
V. APPLY SHIP FORCE
Fig. 3: Apply Transient Force
VI. RESULT OF PM FENDER (FOR 0 DEGREE ANGLE
SHIP IMPACT) EQUIVALENT (VON- MISES) STRESS
Fig. 4: Result of PM Fender (For 0 Degree Angle Ship
Impact)
VII. RESULT OF PM FENDER (FOR 20 DEGREE
ANGLE SHIP IMPACT)
Fig. 5: Result of PM Fender (For 0 Degree Angle Ship
Impact)
VIII. RESULT & DISCUSSION
At Torque Arm
Attachment
Material ST 52 – 355
MPa
0 Degree
20
Degree
Von Misses
Stresses(MPa)
279.11 371.63
Maximum Shear
Stresses(MPa)
149.85 199.81
Factor of Safety 1.27 0.95
Table. 1: Results
From this result we can say that maximum stresses occur at
the torque arm attachment and minimum life is also
generated at the torque arm. For 0 degree ship impact,
fender is capable for sustaining load. For 20 degree ship
impact, fender is not capable to sustain load and minimum
life is generated at the torque arm. So in next chapter we
modify design and try to reduce stresses on torque arm
attachment.
IX. MODIFICATION
Fig. 6: Modification Using Gear Mechanism
In Parallel Motion Fender, when the ship strikes a Fender
First Cone Fender absorb shock energy when the limit of
cone fender is complete. It transmit it load to upper damper
but in some cases when the ship strikes only upper surface
of the Parallel Motion Fender Upper Damper absorb more
energy and its compression movement is more than lower
Damper which restrict the parallel movement so we put gear
mechanism for uniformly guide.
When the Upper Damper Compresses, the another
side gear which attach to the Front Side of the Fender rotates
which move tangentially on the shaft mounted gear. Shaft
having two gear one upper and second lower side. When the
Upper gear rotates at the same time lower gear is also rotate
which results Parallel Operation of Fender.
X. APPLY TRANSIENT FORCE
Fig. 7: Apply Transient Force Using Gear Mechanism

3. Performance Optimization and Fe Analysis of Marine Fender
(IJSRD/Vol. 1/Issue 9/2013/0070)
All rights reserved by www.ijsrd.com 1980
XI. RESULTS OF PM FENDER USING GEAR
MECHANISM (10 DEGREE STRIKE ANGLE)
Fig. 8: Von-Mises Stress (0 Degree Strike Angle)
XII. RESULTS OF PM FENDER USING GEAR
MECHANISM (20 DEGREE STRIKE ANGLE)
Fig. 9: Von-Mises Stress (20 Degree Strike Angle)
XIII. RESULT OF PARALLEL MOTION FENDER
USING GEAR MECHANISM
At Gear Tooth
(Material ST 52 = 355 MPa)
0
Degree
20 Degree
Von Mises Stress (MPa) 51.967 80.299
Maximum Shear Stress 29.265 43.038
Factor of Safety 6.83 4.42
As shown above, the analysis has been performed for the
force applied at normal direction to the frontal panel and 20
degree. Transient analysis has been performed for all 2
cases. The stress value is coming less than the allowable
stress value (80.299 MPa – force applied on 20 degree,
worst case). After modified design, the stress value is
coming much less than the existing design.
XIV. CONCLUSIONS
From above thesis work we can conclude that parallel
motion fender gives better results than any type of fender
because in parallel motion fender side impact is taken care
by torque arm so only parallel impact load is transferred to
cone fender so the life of cone fender increases.
Meanwhile the impact carrying element torque arm
will fail often so in this thesis our aim is to modify parallel
motion fender in such a way so we can eliminate torque
arm.
In gear damper system, when the ship strike the
maximum generated stress in the system is 80.299 MPa
which is less than allowable limit of material. In this design
the factor of safety is 4.42.
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