DEFINITION OF SAFETY FACTOR VOLUMETRIC FINITE ELEMENTS UNDER TRIAXIAL STRESS STATE

This paper evaluates some of the cold-forging features of composite steel preforms of varying titanium carbide contents during cold upsetting under triaxial stress state conditions. A complete experimental investigation is carried out on composite steel preforms of varying titanium carbide contents, namely, 3%TiC and 4%TiC with different lubricating conditions; namely, graphite and zinc stearate and no lubrication. Cylindrical compacts with aspect ratios of 0.42, 0.67, and 1.0 were prepared, sintered, and upset forged at room temperature. The measured barrel radius of curvature is found to have a circular arc because the above relationship is a straight-line one. A relationship is established between the measured barrel radius and the stress ratio parameters of (σθ/σz), (σz/σm), and (σeff/σz) determined under triaxial stress state conditions for both composite steels of varying titanium carbide content. The effect of titanium carbide particle addition in the composite steel, initial preform geometry, and lubricating conditions on the deformation behaviour has been studied, together with the densification route of the composite steel preforms during the deformation.

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Stress-Induced Phase Transformations of an Isotropic Incompressible Elastic Body Subject to a Triaxial Stress State

Journal of Elasticity ◽

10.1007/s10659-006-9059-z ◽

2006 ◽

Vol 84 (3) ◽

pp. 197-221 ◽

Cited By ~ 5

Author(s):

Pilade Foti

Keyword(s):

Stress State ◽

Phase Transformations ◽

Elastic Body ◽

Triaxial Stress ◽

Triaxial Stress State ◽

Incompressible Elastic Body ◽

Body Subject

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Effect of various stress ratio parameters on cold upset forging of irregular shaped billets using graphite as lubricant under plane and triaxial stress state conditions

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2007.03.007 ◽

2008 ◽

Vol 29 (10) ◽

pp. 2089-2103 ◽

Cited By ~ 2

Author(s):

K. Baskaran ◽

R. Narayanasamy

Keyword(s):

Stress State ◽

Stress Ratio ◽

Triaxial Stress ◽

Triaxial Stress State ◽

Upset Forging

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Fracture of sedimentary rocks under a complex triaxial stress state

Mechanics of Solids ◽

10.3103/s0025654416050022 ◽

2016 ◽

Vol 51 (5) ◽

pp. 522-526 ◽

Cited By ~ 10

Author(s):

V. I. Karev ◽

D. M. Klimov ◽

Yu. F. Kovalenko ◽

K. B. Ustinov

Keyword(s):

Stress State ◽

Sedimentary Rocks ◽

Triaxial Stress ◽

Triaxial Stress State

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Linking reservoir geomechanics and time-lapse seismics: Predicting anisotropic velocity changes and seismic attributes

Geophysics ◽

10.1190/1.3122407 ◽

2009 ◽

Vol 74 (4) ◽

pp. W13-W33 ◽

Cited By ~ 46

Author(s):

Jorg V. Herwanger ◽

Steve A. Horne

Keyword(s):

Stress State ◽

Vertical Velocity ◽

Rock Physics ◽

Stress Path ◽

Time Lapse ◽

Triaxial Stress ◽

P Wave ◽

Triaxial Stress State ◽

Wave Velocities ◽

P Wave Velocity

Seismic technology has been used successfully to detect geomechanically induced signals in repeated seismic experiments from more than a dozen fields. To explain geomechanically induced time-lapse (4D) seismic signals, we use results from coupled reservoir and geomechanical modeling. The coupled simulation yields the 3D distribution, over time, of subsurface deformation and triaxial stress state in the reservoir and the surrounding rock. Predicted changes in triaxial stress state are then used to compute changes in anisotropic P- and S-wave velocities employing a stress sensitive rock-physics transform. We predict increasing vertical P-wave velocities inside the reservoir, accompanied by a negative change in P-wave anisotropy [Formula: see text]. Conversely, in the overburden and underburden, we have predicted a slowdown in vertical P-wave velocity and an increase in horizontal velocities. This corresponds to positive change in P-wave anisotropy [Formula: see text]. A stress sensitive rock-physics transform that predicts anisotropic velocity change from triaxial stress change offers an explanation for the apparent difference in stress sensitivity of P-wave velocity between the overburden and the reservoir. In a modeled example, the vertical velocity speedup per unit increase in vertical stress [Formula: see text] is more than twice as large in the overburden as in the reservoir. The difference is caused by the influence of the stress path [Formula: see text] (i.e., the ratio [Formula: see text] between change in minimum horizontal effective stress [Formula: see text] and change in vertical effective stress [Formula: see text]) on vertical velocity. The modeling suggests that time-lapse seismic technology has the potential to become a monitoring tool for stress path, a critical parameter in failure geomechanics.

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