Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Research on Tolerance Analysis of Ship Power Equipment
Peng Yu, Weijia Sheng, Changhua Gao, Shaojun Cai, Fei Yang
Wuhan Second Ship Design and Research InstituteWuhan, Hubei, China

and the adjustments can meet the needs of ship construction.

ABSTRACTKEY WORDS: Ship power equipment, installation
accuracy, Tolerance analysis.

According to the ship power equipment has many external
installation interfaces with high precision requirements andcomplex dimensional chain, the risk of power equipment
installation out of tolerance is greater. Eventually, the overall
installation of propulsion equipment may not meet theaccuracy requirements, or forced assembly, etc. This problem
may reduce the ship’s propulsion efficiency and affect thequality, and also cause safety issues probably. It can even leadto the failure of the entire product project. At the same time, if
the manufacturing and installation accuracy of the parts areblindly improved, the manufacturing cost and period will begreatly increased, and it is difficult to adapt to the application
requirements of actual engineering. Therefore, in the productdesign and construction process, it is necessary to carry out
tolerance analysis of the equipment and formulate a reasonable
and feasible tolerance distribution program from the very
beginning. Through calculation, tolerance analysis and so on,
the designers can verify whether the manufacturing accuracy,
assembly benchmark, assembly process, assembly accuracy ofparts meet the requirements of the product. Then it canoptimize the tolerance distribution program, until achieve thepurpose of ensuring product assembly quality, reducing
production costs, and shortening the period. In order toeffectively eliminate the risk of equipment installation out oftolerance, this paper uses extreme value method, root meansquare method, safety factor-root mean square method, andMonte Carlo method to carry out the tolerance analysis ofequipment assembly, based on the existing domestic
construction capacity. Comparison and analysis of calculation
results by the above different methods puts forward theengineering applicability of different methods, which havestrong engineering guidance. And combined with the actual
construction of the situation, it shows that the equipment
installation accuracy requirements are reasonable and feasible,

INTRODUCTION
In the field of shipbuilding, propulsion system equipment
requires high installation accuracy, which is composed bymany parts that have greatly influence each other. However,
manufacturing deviations and assembly positioning deviationsof each device will accumulate and spread in the actual
assembly process. In the end, the installation of propulsion
equipment may not meet the accuracy requirements, which
will lead to a decrease in propulsion efficiency and productquality, and even cause the safety of system operation,resulting in the failure of the entire product project. At thesame time, if the manufacturing and installation accuracy ofthe parts are blindly improved, the manufacturing cost andperiod will be greatly increased, and it is difficult to adapt tothe application requirements of actual engineering. Therefore,
in the process of product design and construction, the tolerance
analysis of equipment should be carried out at first, and areasonable and feasible tolerance distribution scheme.
Calculation and tolerance analysis can verify whether the
manufacturing accuracy, assembly datum, assembly process
and assembly accuracy of parts meet the requirements ofproducts. Then the tolerance distribution scheme is optimized
to ensure product assembly quality, reduce production cost andshorten production cycle.
Tolerance analysis has been used in aircraft design for many
years (Xu Dan, 2021, 38(5):6, Zhang Li, 2012(7):3 and Zhang
Kaifu, 2006), but its development in ship design is relatively
late (Zhang Jinguo, 2018 and Leng Wenjun, 2017). In order to3883