Measurement of Equation of State of Silicone Elastomer

Silicone Elastomer, (“Sylgard 184 ®”), samples were mounted between copper plates. Manganin stress gauges were placed within the front copper plate, halfway through the Sylgard and at the interface between the Sylgard and the rear copper plate. A series of experiments was performed in which the front plate was impacted by copper plates projected at a range of velocities. It was assumed that a Grüneisen Gamma form with a constant Γ could fit the Equation of State of the sample. A trial set of EoS parameters, including Gamma, was entered into a spreadsheet, then the state variables for the different stress jumps were calculated with the aid of a “Goalseek” function. This enabled the stresses and times for each jump to be calculated. Comparing these predictions with the experimentally determined parameters enabled optimum values of the EoS parameters to be identified.