Elastomer seals are widely used in industry for containing gases and liquids. Seal failurecan have significant environmental and financial implications far beyond the cost of theseal itself. Explosive decompression failure can cause catastrophic cracking of anelastomer seal, causing leakage. The objective of this research was to develop a modellingmethodology to predict the onset of crack damage in elastomer seals under variousoperational conditions.The modelling methodology uses the finite element method to determine the performanceof various elastomers under decompression conditions. The model takes into account sealand groove geometry, the non-linear behaviour of the material and the operationalconditions seen by the seal. The model predicts crack initiations, locations and theorientation of the propagation. The model can also calculate the safe decompression time-required for no damage in the elastomer seal by using the methodology in reverse.To carry out the modelling methodology, certain input data are required. The data wasdetermined by designing and constructing specialist test rigs. A permeation testing facilitywas developed to determine the diffusion, solubility and permeation characteristics ofelastomers subject to gas pressure. The physical behaviour of the elastomers wasdetermined through extensive uniaxial and equibiaxial tensile testing. The nature of thefailure initiation points is determined by microscopic analysis of seal sections.Decompression tests were performed to validate the output of the model.Comparison of the model outputs with the decompression tests show a good correlationbetween the prediction and the occurrences, orientations and positions of cracks.The ability to predict damage in a quantitative manner was previously not available. Themethodology will be developed into a knowledge-based software tool for use in industryto predict damage and develop new materials to resist explosive decompression.
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