Topic
Stress field
About: Stress field is a research topic. Over the lifetime, 11926 publications have been published within this topic receiving 226417 citations.
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TL;DR: In this paper, Coulomb stress interactions and accelerating seismicity before large earthquakes are linked to a stress field that existed before a large earth-quake based on the known source parame- ters of the event.
Abstract: The stress field that existed before a large earth- quake can be calculated based on the known source parame- ters of the event. This stress field can be used to define a region that shows greater seismic moment rate changes prior to the event than arbitrarily shaped regions, allowing us to link two previously unrelated subjects: Coulomb stress interactions and accelerating seismicity before large earthquakes. As an example, we have examined all M≥6.5 earthquakes in California since 1950. While we illustrate the model using seismicity in California, the technique i s general and can be applied to any tectonically active re- gion. We show that where sufficient knowledge of the re- gional tectonics exists, this method can be used to aug- ment current techniques for seismic hazard estimation.
137 citations
TL;DR: In this article, a modified classical lamination theory (CLT) was developed to account for piezoelectric coupling terms under applied electric field, which is capable of predicting the stress field and out-of-plane displacement of laminated PDE layers.
136 citations
TL;DR: Using discrete simulations, the behavior of a model granular material within an annular shear cell is investigated and the range of applicability of the recently introduced constitutive laws for sheared granular materials (based on the inertial number) is delineated.
Abstract: Using discrete simulations, we investigate the behavior of a model granular material within an annular shear cell. Specifically, two-dimensional assemblies of disks are placed between two circular walls, the inner one rotating with prescribed angular velocity, while the outer one may expand or shrink and maintains a constant radial pressure. Focusing on steady state flows, we delineate in parameter space the range of applicability of the recently introduced constitutive laws for sheared granular materials (based on the inertial number). We discuss the two origins of the stronger strain rates observed near the inner boundary, the vicinity of the wall and the heteregeneous stress field in a Couette cell. Above a certain velocity, an inertial region develops near the inner wall, to which the known constitutive laws apply, with suitable corrections due to wall slip, for small enough stress gradients. Away from the inner wall, slow, apparently unbounded creep takes place in the nominally solid material, although its density and shear to normal stress ratio are on the jammed side of the critical values. In addition to rheological characterizations, our simulations provide microscopic information on the contact network and velocity fluctuations that is potentially useful to assess theoretical approaches.
136 citations
TL;DR: In this article, a three-dimensional (3D) finite element model that considers the coupled effects of seepage, damage, and the stress field is introduced, and numerically simulated results show that the fractures from a vertical wellbore propagate in the maximum principal stress direction without branching, turning, and twisting in the case of a large difference in the magnitude of the far field stresses.
Abstract: The failure mechanism of hydraulic fractures in heterogeneous geological materials is an important topic in mining and petroleum engineering. A three-dimensional (3D) finite element model that considers the coupled effects of seepage, damage, and the stress field is introduced. This model is based on a previously developed two-dimensional (2D) version of the model (RFPA2D-Rock Failure Process Analysis). The RFPA3D-Parallel model is developed using a parallel finite element method with a message-passing interface library. The constitutive law of this model considers strength and stiffness degradation, stress-dependent permeability for the pre-peak stage, and deformation-dependent permeability for the post-peak stage. Using this model, 3D modelling of progressive failure and associated fluid flow in rock are conducted and used to investigate the hydro-mechanical response of rock samples at laboratory scale. The responses investigated are the axial stress–axial strain together with permeability evolution and fracture patterns at various stages of loading. Then, the hydraulic fracturing process inside a rock specimen is numerically simulated. Three coupled processes are considered: (1) mechanical deformation of the solid medium induced by the fluid pressure acting on the fracture surfaces and the rock skeleton, (2) fluid flow within the fracture, and (3) propagation of the fracture. The numerically simulated results show that the fractures from a vertical wellbore propagate in the maximum principal stress direction without branching, turning, and twisting in the case of a large difference in the magnitude of the far-field stresses. Otherwise, the fracture initiates in a non-preferred direction and plane then turns and twists during propagation to become aligned with the preferred direction and plane. This pattern of fracturing is common when the rock formation contains multiple layers with different material properties. In addition, local heterogeneity of the rock matrix and macro-scale stress fluctuations due to the variability of material properties can cause the branching, turning, and twisting of fractures.
136 citations
TL;DR: In this article, the analysis of an automotive suspension component which demonstrates this phenomenon was reported. But, the analysis was performed using a critical distance approach, which was not suitable for the case of a single component.
136 citations