Reduced Time Simulation of Rubber in Oilfield Environments
Alex Arzoumanidis (Psylotech)
Engineering Mechanics and Materials in the Oilfield
Wed 10:45 - 12:15
CIT 227
Reduced time constitutive models have been shown to effectively simulate nonlinear viscoelastic (NLVE) behavior of elastomers, accommodating time, rate, large deformation, temperature, hydrostatic pressure, solvent absorption and damage effects. Such NLVE effects seriously complicate simulation of sealing components used in the oil patch. This work contrasts reduced time models based on 1/free volume and 2/free energy. Strain rate, large deformation, and temperature effects are measured on a Viton elastomer, then compared to prediction with the two models. The foundation of both reduced time models is a self-consistent, accurate linear viscoelastic property matrix. The 3D property matrix is experimentally determined using a novel technique based on a bi-axial extensometer. Dynamic Poisson's ratio and dynamic Young's modulus are measured in isothermal frequency sweeps on a single tensile specimen, which are then shifted into frequency domain master curves. These master curves are used to infer time domain bulk and shear moduli Prony Series, needed for the simulation. Viton specimens are tested to 50% engineering strain at 3 strain rates, varied by an order of magnitude,. The test is repeated at 2 temperatures. Model parameters are determined by one of these ramp tests. Experimental results are compared to simulation with the free energy and free volume reduced time models.