Analysis of Large-Sized O-Rings

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Analysis of Large-Sized O-Rings

Finite element analysis of large-sized O-rings used in deep-ocean pressure chambers
Wentao Song, Weicheng Cui et. al.
13 pages
2021

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Open: Finite element analysis of large-sized O-rings

Abstract

A proper criterion to guide how to determine the cross-section diameter of non-standard large-sized O-rings used in deep-ocean pressure chambers (DOPCs) is absent. To design a large-sized O-ring only by scale-up could be a lack of persuasiveness, and it will probably cause the increase of cost. This paper gives a detailed study on the static sealing performance of O-rings by finite element analysis (FEA). The results show that the influence of the inside diameter of O-rings can be ignored, and the O-rings with a large cross-section diameter may not be applicable to the high-pressure DOPCs, but it can allow a larger sealing clearance to be used in the low-pressure DOPCs. The reference values of safe sealing pressure with different cross-section diameters and different sealing clearances are ascertained. An improved criterion to guide how to determine the cross-section diameter of non-standard large-sized O-rings used in DOPCs is proposed. The results obtained in this paper can provide a more convincing guideline for the O-ring sealing design not only in DOPCs but also in the similar pressure vessels.

Introduction:

Pressure testing with a deep-ocean simulation system (DOSS) is required by all leading classification societies worldwide to ascertain the quality of design and fabrication of submersibles. It is an ideal means to validate the safe use of deep-ocean equipment and is a vital tool to check whether the pressure structure is safe and reliable. The major component of a DOSS is a deep-ocean pressure chamber (DOPC), whose sealing design is a challenging task due to the large size of sealing surfaces and the high sealing pressure.1,2.

The sealing type of DOPCs is generally static, because there is no relative motion between seals and sealing surfaces when pressure chambers are in operation. The most common static seal used in DOPCs is the elastomer O-ring, because it has a simple structure with light weight, and is convenient to be replaced when it is aging or deteriorated. The test results show that the limit for pressure level of O-rings can be up to 350MPa, which can meet the needs of the pressure..