TS-102
The Modular Method for Design and Production of Marine Engine Plants
(The Determination of the Importance Degree of Modules in Shipbuilding)
Kenji ISHIDA*, YU Hongliang*, Takeshi HASHIMOTO*, Nobuyosi YONEKURA** and Isamu SATO***
ABSTRACT
Modular outfitting method plays an important role in shipbuilding, including installation of engine room machinery to improve the effectiveness, save man-hour and have bigger competitive in the world. It is a very important subject to user and shipbuilder how to guarantee the reliability of power plant from the start of shipbuilding, i.e. how to distribute reasonably reliability to each module because the different module has its different role in system. In the paper a new method to determine importance degree is presented. The fuzzy function in this method is used to determine the importance degree because it is difficult to precisely determine the parameters of probability distributions and detailed data. The method proposed in this paper also can be used in other engineering calculation.
Key words: Module, Reliability, Importance degree, Necessary, Failure degree, Influence degree, Influenced degree, Fuzzy function
1 .INTRODUCTION
Shipbuilders have become extremely competitive in the world market over the past 20 years. This has forced the ones who wish to remain in the business to continually improve designs and production strategies. Modular construction of its engine rooms has provided the shipbuilder with a number of benefits and also some concerns.
Modules used in ship are mainly divided into two groups [3,4] :
a) The type attached importance to system
b) The type attached importance to disposition The type of former has a wider use in shipbuilding. The main modules of former type used in ship are listed as follows [3 ,4] :
a) Engine control room
b) High temperature fresh water cooling system
c) Low temperature fresh water cooling system.
d) Sea water system consisting of sea water cooling, fire fighting, bilge and ballast.
e) Generator sets.
f) Integrated Ventilation system.
g) Sewage system.
h) Fuel oil separators including heaters, pumps, and sludge oil tank,
i) Refrigeration and air condition system,
j) Starting, working and control system,
k) Integrated fire fighting system,
I) Lube oil system.
n) Boiler system
m) Integrated cable system
o) Main engine
It is a very important subject to user and shipbuilder how to guarantee the reliability of power plant from the start of shipbuilding, i.e. how to guarantee the reliability of each module. A method must be found to resolve how to distribute reasonably reliability to each module because the different module has its different demand of reliability. There are many methods to distribute the reliability to each module according the general demand of reliability of power plant. One of these evaluating methods is that the reliability of module is got based on its importance degree in power plant. Therefore the module of high importance degree must be noticed in design, outfitting or system of check and supervision.
2.SYSTEM DEGREE MODELING FOR THE IMPORTANCE DEGREE
Necessity, failure degree, influence degree, and influenced degree of each module may be used to determine the importance degree to guarantee the reliability of power plant in this paper, i.e. importance degree =f (necessity, failure degree, influence degree, influenced degree).
Traditionally the importance degree is carried out on a probabilistic basis [7] .
*Kobe University of Mercantile Marine
Fukae, Higashinada-ku, Kobe 658-0022, Japan
Fax:+81-78-431-6365
**MEC Engineering Service
***NKK Logistic
