Discriminating the Viscoelastic Properties from Flow-Dependent Behavior in Porous Material

Abstract

The porous material is a biphasic material composed of a solid skeleton and a fluid (liquid or gas) filled the voids In addition to the effect of the rate-dependent interaction between two phases the solid phase may exhibit intrinsic viscoelastic behavior The physical mechanisms are different in that flow-dependent behavior varies with specimen size while viscoelastic behavior does not Strange et al (2013) offer an approximate model in which the poroviscoelastic load-relaxation is the product of the poroelastic and viscoelastic responses based on constant intrinsic Poisson's ratio The present research extends the Strange’s approximate model to include the poroviscoelastic material with time-dependent intrinsic Poisson’s ratio We simulate three common experiments by finite element software ABAQUS and use the numerical data of different specimens to characterize the poroviscoelasticity of porous material For poroviscoelastic materials with time-dependent intrinsic Poisson’s ratios the characterizations are carried out by two methods: one is based on the modified approximate model and the other is based on the solutions obtained from Laplace transform and numerical inverse transform To obtain the intrinsic viscoelastic behavior including Poisson’s ratio without prior assumption we suggest to measure lateral displacements in unconfined compression test or the lateral loads in confined compression tests when the intrinsic viscoelastic behavior is dominated Changing the specimen size and using appropriate normalization allow us to separate the poroelastic and viscoelastic responses and thus determine both properties successfully

Date of Award	2014 Aug 22
Original language	English
Supervisor	Yu-Yun Lin (Supervisor)