Prediction of Extrusion Failures of O-Ring Seals

Primary aim of this paper is to investigate the mechanical behavior of an O-ring seal made of NBR rubber material using finite element method. Further aim is to identify the O-ring's critical locations where it can fail under normal operating conditions. For these a large-strain viscoelastic material model was set up. The recommended strain range where the material model should be sufficient is 0-100 % for normal conditions, but when the effect of overload or the temperature is the question, the strain range should be 0-150 %. From designer point of view, a large-strain viscoelastic material model with a 5 parameter Mooney-Rivlin term is appropriate. To make sure the material model′s accurate response, uniaxial tension, pure shear and equibiaxial measurements are needed, completed with dynamic measurements with a DMTA machine. The results show two critical locations where the failure of the O-ring is expected. One is on the edge of the O-ring near the gap, when friction is present, the other one is under the edge near the gap.

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“…2 (b). Eshel studied the extrusion of O-rings and proposed a theoretical model to estimate the failure in this mode [5]. In Fig.…”

Section: Short Literature Review Of Failure Of O-ringsmentioning

confidence: 99%

Large Strain Viscoelastic Material Model for Deformation, Stress and Strain Analysis of O-rings

Szabó

Váradii

2018

Period. Polytech. Mech. Eng.

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“…This is very close to the limit in Parker O-ring Handbook (C max = 0.5 mm), and these limits are usually strict. 3,10 (3) There is no direct experimental verification, and this kind of experiment will cost a lot and is challenging due to the high-pressure and the large size of O-rings. Based on the practical engineering application, the maximum equivalent strains of the O-rings in the DOCP3 is about 0.64, while the value in the DOCP4 is about 0.6679.…”

Section: Discussion Verificationmentioning

confidence: 99%

“…Equation (1) means that the contact stress s p is always higher than the sealing pressure P with the amount of the initial contact stress s 0 that is determined by the sealing clearance C. However, if the sealing pressure P is too high, a portion of the O-ring could be squeezed into the clearance between two sealing surfaces, which is called extrusion, as is shown in Figure 2(d). 3,10 The automatic sealing mechanism is an important criterion to judge the sealing failure of an O-ring in engineering and FEA, which can be called the Stress Criterion.…”

Section: Automatic Sealing Mechanismmentioning

confidence: 99%

“…The test results show that the limit for pressure level of O-rings can be up to 350 MPa, which can meet the needs of the pressure testing with a DOSS. 2,3 Figure 1 shows a common O-ring sealing design used in many DOPCs. [4][5][6][7][8] The O-rings used in DOPCs usually have a large inside diameter d 1 and a large cross-section diameter d 2 , which are both non-standard sizes.…”

Section: Introductionmentioning

confidence: 99%

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Finite element analysis of large-sized O-rings used in deep-ocean pressure chambers

Song

Cui

2021

Advances in Mechanical Engineering

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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.

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“…In one mode of failure, the whole elastomer squeezes into the tight space above the step, and escape from the sealing site (Eshel 1984) (Fig. 1c).…”

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confidence: 99%