Ultimate tensile properties of elastomers. III - Dependence of the failure envelope on crosslink density
Ultimate tensile properties of amorphous unfilled elastomers - dependence of failure envelope on crosslink density
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Ultimate tensile properties of amorphous unfilled elastomers - dependence of failure envelope on crosslink density
Dynamic-mechanical properties of sterilizable polybutadiene elastomer after high temperature exposure
Elastomer elastic deformation response in multiaxial stress field shown identical to uniaxial stress response
Contamination of spacecraft components with planetary and foreign object debris is a growing concern. Face seals separating the spacecraft cabin from the debris filled environment are particularly susceptible; if the seal becomes contaminated there is potential for decreased performance, mission failure, or catastrophe. In this study, silicone elastomer O-rings were contaminated with JSC- 1A lunar regolith and their leak rate performance was evaluated. The leak rate values of contaminated O-rings at four levels of seal compression were compared to those of as-received, uncontaminated, O-rings. The results showed a drastic increase in leak rate after contamination. JSC-1A contaminated O-rings lead to immeasurably high leak rate values for all levels of compression except complete closure. Additionally, a mechanical method of simulant removal was examined. In general, this method returned the leak rate to as-received values.
The National Aeronautics and Space Administration has been developing a novel docking system to meet the requirements of future exploration missions to low-Earth orbit and beyond. A dynamic gas pressure seal is located at the main interface between the active and passive mating components of the new docking system. This seal is designed to operate in the harsh space environment, but is also to perform within strict loading requirements while maintaining an acceptable level of leak rate. In this study, a candidate silicone elastomer seal was designed, and multiple subscale test articles were manufactured for evaluation purposes. The force required to fully compress each test article at room temperature was quantified and found to be below the maximum allowable load for the docking system. However, a significant amount of scatter was observed in the test results. Due to the stochastic nature of the mechanical performance of this candidate docking seal, a statistical process control technique was implemented to isolate unusual compression behavior from typical mechanical performance. The results of this statistical analysis indicated a lack of process control, suggesting a variation in the manufacturing phase of the process. Further investigation revealed that changes in the manufacturing molding process had occurred which may have influenced the mechanical performance of the seal. This knowledge improves the chance of this and future space seals to satisfy or exceed design specifications.
A ferrite-core holder, fabricated by casting an elastomer in a simple mold, simplifies the assembly of modular matrix units for computers. Use of the device permits the core leads to be multiply threaded and soldered to terminals, without requiring intermediate terminals.
Extensometer, with a calibrated shaft, measures the elongation of elastomers and automatically records this distance on a chart. It is adaptable to almost any tensile testing machine and is fabricated at a relatively low cost.
Smooth, unfoamed elastomer is unaffected by common acids, alkalies, and organic solvents. Its thermal stability, chemical resistance, and physical properties make it of interest for various applications.
Vulcanizable elastomers for use with liquid oxygen
Elastomer synthesis for copolymerization with liquid fluorine
Fracture energy and mechanical properties of polyurethane elastomers
Synthesis of elastomers for use with liquid fluorine
Vulcanizable elastomers suitable for contact with liquid oxygen, discussing preparation, mechanical properties, transition temperature and structure
Annotated bibliography of vulcanicable elastomers for use with liquid oxygen
Polyperfluorobutadiene reactions for developing oxidation resistant elastomers for space propulsion
Improvement additives for adhesive and elastomer performance