Stress field

About: Stress field is a research topic. Over the lifetime, 11926 publications have been published within this topic receiving 226417 citations.

Importance of poroelastic coupling in dynamically active aquifers of the Po river basin, Italy

Abstract: Uncoupling between the flow field and the stress field in pumped aquifers is the basis of the classical groundwater hydrology. Recently, some authors have disputed the assumption of uncoupling with regard to both fluid dynamics and porous medium deformation. The issue is very important as it could undermine the traditional approach to simulate subsurface flow, analyze pumping tests, and predict land subsidence caused by fluid withdrawal. The present paper addresses the problem of coupling versus uncoupling in the Po river plain, a normally consolidated and normally pressurized basin which has experienced in the last 50 years a pronounced pore pressure drawdown because of water and gas removal and where a large hydromechanical database is available from the ground surface down to 4000 m depth. A numerical study is performed which shows that the matrix which relates flow to stress is very similar to the capacity matrix of the uncoupled flow equation. A comparison of results obtained with the finite element integration of the coupled and uncoupled models indicates that pore pressure is rather insensitive to coupling anywhere within the pumped formation while in the adjacent aquitard-aquifer units, coupling induces a slight overpressure which quickly dissipates in time with a small initial influence on medium deformation, and specifically on land subsidence. As a major consequence the uncoupled solutions to the fluid dynamic and the structural problems appear to be fully warranted on any timescale of practical interest in a typical normally consolidated and pressurized basin.

Singular Stress Field Near the Corner of Jointed Dissimilar Materials

Abstract: In this paper, the characteristics of the stress field near a corner of jointed dissimilar materials are studied as a plane problem. It is found that the order of singularity is dependent not only on the elastic constants of materials and the local geometry of corner, but also on the deformation mode. The dependence of the order of singularity was established for the case of mode I and the case of mode II. An explicit closed-form expression is given for the singular stress field at the close vicinity of the corner, in which the stress field is expressed as a sum of the symmetric state with a stress singularity of 1/r 1-λ1 and the skew symmetric state with a stress singularity of 1/r 1-λ2 . When both λ1 and λ2 are real the singular stress field around the point singularity is defined in terms of two constants K 1 , λ1 , K 11 , λ2 , as in the case of crack problems.

Stress fields around defects and fibers in a polymer using carbon nanotubes as sensors

Abstract: Raman spectroscopy was used to map the stress distribution in the vicinity of discontinuities in a polymer using single-wall nanotubes seeded in the specimen. In the case of a hole in a polymer matrix subjected to unidirectional stress, the experimental stress field compared well with the classical linear elasticity solution. For a single glass fiber embedded in a polymer, the tangential thermal residual stress in the vicinity of the fiber was picked up by Raman spectroscopy and is in satisfactory agreement with a standard two-phase concentric cylinder model.