Two complementary stress release processes based on departures from Omori’s law

2015 ◽  
Vol 20 (1) ◽  
pp. 41-55 ◽  
Author(s):  
Marisol Monterrubio Velasco ◽  
Maria-Dolors Martínez ◽  
Xavier Lana
Keyword(s):  
Stress Release ◽  
Omori’S Law ◽  
Release Processes

Explicit formulae for stationary distributions of stress release processes

2000 ◽  
Vol 37 (2) ◽  
pp. 315-321 ◽  
Author(s):  
K. Borovkov ◽  
D. Vere-Jones
Keyword(s):  
Closed Form ◽  
Stationary Distribution ◽  
Exponential Function ◽  
Markov Models ◽  
Risk Process ◽  
Stress Release ◽  
Stationary Distributions ◽  
Explicit Formulae ◽  
Tectonic Forces ◽  
Release Processes

Stress release processes are special Markov models attempting to describe the behaviour of stress and occurrence of earthquakes in seismic zones. The stress is built up linearly by tectonic forces and released spontaneously when earthquakes occur. Assuming that the risk is an exponential function of the stress, we derive closed form expressions for the stationary distribution of such processes, the moments of the risk, and the autocovariance function of the reciprocal risk process.

scholarly journals Determination of Residual Stress Fields in a Thermally Grown Oxide under Thermal Cycling Loadings, Using XRD and Raman Spectroscopy — Correlations with Microstructural States

2014 ◽  
Vol 996 ◽  
pp. 890-895
Author(s):  
Felaniaina Rakotovao ◽  
Zhao Jun Tao ◽  
Jean Luc Grosseau-Poussard ◽  
Benoit Panicaud ◽  
Gilles Bonnet ◽  
...  
Keyword(s):  
Residual Stress ◽  
Raman Spectroscopy ◽  
Residual Stresses ◽  
Thermally Grown Oxide ◽  
Stress Fields ◽  
Stress Release ◽  
Thermal Oxide ◽  
Long Time ◽  
Release Processes

The presence of residual stresses in thermal oxide layers has been recognized for a long time. In the present work, the mechanical fields for chromia oxide are determined either by XRD or Raman spectroscopy. In addition, the microstructure of the chromia films is investigated ant its influence on the evolution of the stress release processes is analyzed.

scholarly journals Rake rotation introduces ambiguity in the formulation of slip-dependent constitutive models: slip modulus or slip path?

2014 ◽  
Vol 57 (5) ◽  
Author(s):  
Andrea Bizzarri
Keyword(s):  
Seismic Moment ◽  
A Priori ◽  
Constitutive Models ◽  
Stress Release ◽  
Coseismic Slip ◽  
Slip Vector ◽  
Analytical Formulation ◽  
Grid Dispersion ◽  
Governing Law ◽  
Release Processes

<p>The linear slip–weakening (SW) law, predicting that the traction decreases for increasing fault slip, is one of the most widely adopted governing models to describe the traction evolution and the stress release processes occurring during coseismic slip failures. We will show that, contrary to other constitutive models, the SW law inherently poses the problem of considering the Euclidean norm of the slip vector or its cumulative value along its path. In other words, it has the intrinsic problem of its analytical formulation, which does not have a solution a priori. By considering a fully dynamic, spontaneous, 3–D rupture problem, with rake rotation allowed, in this paper we explore whether these two formulations can lead to different results. We prove that, for homogeneous configurations, the two formulations give the same results, with a normalized difference less than 1%, which is comparable to the numerical error due to grid dispersion. In particular, we show that the total slip, the resulting seismic moment, the fracture energy density, the slip–weakening curve and the energy flux at the rupture front are practically identical in the two formulations. These findings contribute to reconcile the results presented in previous papers, where the two formulations have been differently employed. However, this coincidence is not the rule. Indeed, by considering models with a highly heterogeneous initial shear stress distribution, where the rake variation is significant, we have also demonstrated that the overall rupture history is quite different by assuming the two formulations, as well as the fault striations, the traction evolution and the scalar seismic moment. In this case the choice of the analytical formulation of the governing law does really matter.</p>

Explicit formulae for stationary distributions of stress release processes

2000 ◽  
Vol 37 (02) ◽  
pp. 315-321 ◽  
Author(s):  
K. Borovkov ◽  
D. Vere-Jones
Keyword(s):  
Closed Form ◽  
Stationary Distribution ◽  
Exponential Function ◽  
Markov Models ◽  
Risk Process ◽  
Stress Release ◽  
Stationary Distributions ◽  
Explicit Formulae ◽  
Tectonic Forces ◽  
Release Processes

Stress release processes are special Markov models attempting to describe the behaviour of stress and occurrence of earthquakes in seismic zones. The stress is built up linearly by tectonic forces and released spontaneously when earthquakes occur. Assuming that the risk is an exponential function of the stress, we derive closed form expressions for the stationary distribution of such processes, the moments of the risk, and the autocovariance function of the reciprocal risk process.

Residual Stress Release and Its Effects on the Fatigue Strength of Typical Welded Joints in Cone-Cylinder Pressure Structures

2021 ◽  
Vol 111 ◽  
pp. 102673
Author(s):  
Liangbi Li ◽  
Jingxi Zhang ◽  
Yiwen Zhang ◽  
Deqin Zhu ◽  
Zhengquan Wan ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Welded Joints ◽  
Cylinder Pressure ◽  
Stress Release

scholarly journals Reconstruction of river valley evolution before and after the emplacement of the giant Seymareh rock avalanche (Zagros Mts., Iran)

2019 ◽  
Vol 7 (4) ◽  
pp. 929-947 ◽  
Author(s):  
Michele Delchiaro ◽  
Marta Della Seta ◽  
Salvatore Martino ◽  
Maryam Dehbozorgi ◽  
Reza Nozaem
Keyword(s):  
Slope Failure ◽  
Rock Avalanche ◽  
Evolutionary Model ◽  
River Valley ◽  
Time To Failure ◽  
Stress Release ◽  
Seismic Triggering ◽  
Rock Creep ◽  
Before And After

Abstract. The Seymareh landslide, detached ∼10 ka from the northeastern flank of the Kabir-kuh fold (Zagros Mts., Iran), is recognized worldwide as the largest rock slope failure (44 Gm3) ever recorded on the exposed Earth surface. Detailed studies have been performed that have described the landslide mechanism and different scenarios have been proposed for explaining the induced landscape changes. The purpose of this study is to provide still missing time constraints on the evolution of the Seymareh River valley, before and after the emplacement of the Seymareh landslide, to highlight the role of geomorphic processes both as predisposing factors and as response to the landslide debris emplacement. We used optically stimulated luminescence (OSL) to date lacustrine and fluvial terrace sediments, whose plano-altimetric distribution has been correlated to the detectable knickpoints along the Seymareh River longitudinal profile, allowing the reconstruction of the evolutionary model of the fluvial valley. We infer that the knickpoint migration along the main river and the erosion wave propagation upstream through the whole drainage network caused the stress release and the ultimate failure of the rock mass involved in the landslide. We estimated that the stress release activated a mass rock creep (MRC) process with gravity-driven deformation processes occurring over an elapsed time-to-failure value on the order of 102 kyr. We estimated also that the Seymareh damming lake persisted for ∼3500 years before starting to empty ∼6.6 ka due to lake overflow. A sedimentation rate of 10 mm yr−1 was estimated for the lacustrine deposits, which increased up to 17 mm yr−1 during the early stage of lake emptying due to the increased sediment yield from the lake tributaries. We calculated an erosion rate of 1.8 cm yr−1 since the initiation of dam breaching by the Seymareh River, which propagated through the drainage system up to the landslide source area. The evolutionary model of the Seymareh River valley can provide the necessary constraints for future stress–strain numerical modeling of the landslide slope to reproduce the MRC and demonstrate the possible role of seismic triggering in prematurely terminating the creep-controlled time-to-failure pathway for such an extremely large case study.

PIXE MICROBEAM IN LOCALIZING METALS RELEASED FROM DENTAL AND ORTHOPEDIC IMPLANTS

2005 ◽  
Vol 15 (03n04) ◽  
pp. 187-193
Author(s):  
PIETRO PASSI ◽  
ANGELA ZADRO ◽  
SILVIO GALASSINI ◽  
GIULIANO MOSCHINI ◽  
PAOLO ROSSI ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Release Rate ◽  
Pure Titanium ◽  
Orthopedic Implants ◽  
Elemental Distribution ◽  
Commercially Pure Titanium ◽  
Metal Release ◽  
Hip Prostheses ◽  
Commercially Pure ◽  
Release Processes

The release of metals and other elements from dental and orthopedic implants into the tissues has been a matter of numerous studies. However, the conditions that favor such a phenomenon have not been completely understood so far. PIXE microbeam technique has been applied to study the spatial distribution of the elements released from the implants. Subjects of interest have been implants made from commercially pure titanium, Ti -6 Al -4 V alloy and 316 LWM surgical steel. Block sections of five dental implants, as well as tissues surrounding one metal spine plate and two hip prostheses, have been examined. Rabbit bones containing copper inclusions have been taken for microbeam analysis to complete the study about the metal release processes. Samples from the tissues and bone slices have been analyzed using PIXE microbeam setup at National Laboratories of Legnaro, Italy. Traces of the implant metals, including titanium but with the exception of vanadium, were found in the surrounding tissues and maps of their elemental distribution at different distances from the contact surface with implants have been obtained. The origin and the differences of the release rate of the observed metals have been discussed.

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