| Elastomers are commonly used in engineering design because of their unique properties. As gaskets and seals, elastomers are subjected to chemical, mechanical, and thermal loading. The heat transfer and resulting temperature drop across an elastomer to metal interface may be a design constraint; prediction of contact resistance could be required for reliable design. Existing contact resistance models, developed for interfaces of two hard materials, are not applicable to elastomeric contacts because of the intrinsic properties of elastomers. Therefore, measurement of the contact resistance for such interfaces is necessary.; In this work, the temperature profiles in silicone rubber specimens were measured to allow determination of the contact resistance at each interface, as well as the total resistance of metal-elastomer-metal joints. Measurements were made in both ambient air and vacuum environments for a heat flux range of 1500-10000 W/m{dollar}sp2{dollar} and an apparent contact stress of 0.048 to 0.24 MPa. The load was applied with dead weights on a freely moving platform, so an LVDT was used to measure deformation of the specimen due to mechanical and thermal loads, and the positions of the thermocouples in the specimen corrected accordingly for the calculation of the temperature gradient.; The data reveal a large difference between the interfacial resistances for the hot and the cold interfaces. The contact resistances are strongly dependent on temperature and are a weaker function of the contact stress. The interface resistance is {dollar}sim{dollar}25% of the total resistance for a 4.76 mm thick specimen. As the thickness of the elastomer is decreased or its thermal conductivity increased, the interface resistance assumes a larger role in the overall temperature drop. The differences in the measured contact resistances for the ambient air and vacuum environments suggest that air trapped at the interface may increase the interface resistance.; A finite difference based analytical model, that explains qualitatively the behavior of thermal contact resistance of elastomer to metal interfaces under different applied conditions, is proposed. The concept of an effective thermal conductivity, that accounts for the effects of both constriction and gap resistances in a single parameter, is introduced to explain the mechanism of thermal contact resistance at such interfaces. |
