Failure behavior of rubber O-ring under cyclic exposure to high-pressure hydrogen gas

Abstract This paper presents the effects of hydrogen pressure, ambient temperature and pressure cycle pattern on fracture behavior of O-rings moulded from a peroxide-crosslinked EPDM rubber with white reinforcing filler under cyclic exposure to high-pressure hydrogen gas. By using a developed durability tester which enables the O-rings to expose cyclically high-pressure hydrogen gas, pressure cycle tests were performed at hydrogen pressures ranging from 10 to 70 MPa and ambient temperatures ranging from 30 to 100 °C under two pressure cycle patterns (test frequencies). The cyclic hydrogen exposure caused cracks in the O-rings, and their crack damage became more serious with an increase in the hydrogen pressure and the ambient temperature. The serious crack damage under high temperature is believed to be due to degradation of mechanical properties with increasing ambient temperature. At a hydrogen pressure of 10 MPa, cracks (blisters) caused by bubbles formed from supersaturated hydrogen molecules after decompression were observed. At a hydrogen pressure of 35 MPa or more, a large volume increase of the O-rings was observed by swelling; then, its volume increase induced extrusion fracture of the O-rings in addition to blister fracture. The crack damage also became more serious with a decrease in test frequency. The effect of the test frequency on the crack damage of the O-rings is presumed to be attributed to time-dependent crack growth behavior of the EPDM rubber.

[1]  J. Yamabe,et al.  Hydrogen-induced degradation of rubber seals , 2012 .

[2]  A. Thomas,et al.  Rupture of Rubber. III. Determination of Tear Properties , 1955 .

[3]  Alan N. Gent,et al.  Internal rupture of bonded rubber cylinders in tension , 1961, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[4]  P. B. Lindley,et al.  Cut growth and fatigue of rubbers. II. Experiments on a noncrystallizing rubber , 1964 .

[5]  Junichiro Yamabe,et al.  Influence of fillers on hydrogen penetration properties and blister fracture of rubber composites for O-ring exposed to high-pressure hydrogen gas , 2009 .

[6]  D. J. Montgomery,et al.  The physics of rubber elasticity , 1949 .

[7]  G. J. van Amerongen,et al.  Diffusion in Elastomers , 1964 .

[8]  Erwan Verron,et al.  Comparison of Hyperelastic Models for Rubber-Like Materials , 2006 .

[9]  Alan N. Gent,et al.  Nucleation and Growth of Gas Bubbles in Elastomers , 1969 .

[10]  Simon Atkinson.  Decompression modelling of elastomer seals promises to eliminate downtime , 2002 .

[11]  B. Briscoe,et al.  “Explosive Decompression Failure” of Rubbers: A Review of the Origins of Pneumatic Stress Induced Rupture in Elastomers , 1994 .

[12]  J. Yamabe,et al.  Crack Growth Behavior of Sealing Rubber under Static Strain in High-Pressure Hydrogen Gas , 2011 .

[13]  M. S. Plesset,et al.  On the stability of gas bubbles in liquid-gas solutions , 1950 .

[14]  Phil Embury,et al.  High-pressure gas testing of elastomer seals and a practical approach to designing for explosive decompression service☆ , 2004 .

[15]  A. Demarez,et al.  Diffusion of hydrogen in mild steel , 1954 .

[16]  G. H. Lindsey.  Triaxial Fracture Studies , 1967 .

[17]  J. Yamabe,et al.  Nanoscale fracture analysis by atomic force microscopy of EPDM rubber due to high-pressure hydrogen decompression , 2011 .

[18]  Andrew Stevenson,et al.  Fracture of Elastomers by Gas Decompression , 1995 .

[19]  B. Briscoe,et al.  Internal Crack Symmetry Phenomena during Gas-Induced Rupture of Elastomers , 1992 .

[20]  J. Yamabe,et al.  Influence of carbon black on decompression failure and hydrogen permeation properties of filled ethylene-propylene–diene–methylene rubbers exposed to high-pressure hydrogen gas , 2011 .