Laboratory study on the effects of fault waviness on granodiorite stick-slip instabilities

2020 ◽  
Vol 221 (2) ◽  
pp. 1281-1291
Author(s):  
Yan-Qun Zhuo ◽  
Yanshuang Guo ◽  
Shunyun Chen ◽  
Yuntao Ji
Keyword(s):  
Laboratory Study ◽  
Contact Area ◽  
Surface Profile ◽  
Fault Slip ◽  
Stick Slip ◽  
Fault Surface ◽  
State Dependent ◽  
Gradual Evolution ◽  
Large Contact Area ◽  
Contact Distribution

SUMMARY The effects of fault waviness on the fault slip modes are unclear. Laboratory study on the effects of the centimetre-scale fault contact distribution, which is mainly controlled by the fault waviness, on granodiorite stick-slip instabilities may help to unveil some aspects of the problem. The fast and slow stick-slip motions were separately generated in two granodiorite samples of the same roughness but different fault contact distributions in the centimetre scale in the laboratory. The experimental results show the following: (1) the fault with the small contact area and heterogeneous contact distribution generates fast stick-slip instabilities, while the fault with the large contact area and homogeneous contact distribution produces slow stick-slip events; (2) the nucleation processes of the fast stick-slip events are characterized by abrupt changes once the nucleation zones expand to the critical nucleation length that is observed to be shorter than the fault length, while the slow stick-slip events appear as a gradual evolution of the nucleation zones leading to total fault sliding. These indicate that, unlike the micron-scale fault contact distribution controlled by roughness, which depends mainly on the grain size of the abrasives used for lapping the fault surface, the centimetre-scale fault contact distribution, which depends mainly on the waviness of the fault surface profile, also plays an important role in the fault slip modes. In addition, the effects of the fault waviness on the fault friction properties are preliminarily analysed based on the rate- and state-dependent friction law.

A critical look at the Wallace-Bott hypothesis in fault-slip analysis

2013 ◽  
Vol 184 (4-5) ◽  
pp. 299-306 ◽  
Author(s):  
Richard J. Lisle
Keyword(s):  
Shear Stress ◽  
Maximum Shear Stress ◽  
Fault Slip ◽  
Shear Stresses ◽  
Homogeneous State ◽  
Slip Direction ◽  
Fault Surface ◽  
State Of Stress ◽  
Simultaneous Movement

AbstractThe assumption is widely made that slip on faults occurs in the direction of maximum resolved shear stress, an assumption known as the Wallace-Bott hypothesis. This assumption is used to theoretically predict slip directions from known in situ stresses, and also as the basis of palaeostress inversion from fault-slip data. This paper examines different situations in relation to the appropriateness of this assumption. Firstly, it is shown that the magnitude of the shear stress resolved within a plane is a function with a poorly defined maximum direction, so that shear stress values greater than 90% of the maximum occur within a wide angular range (± 26°) degrees. The situation of simultaneous movement on pairs of faults requires slip on each fault to be parallel to their mutual line of intersection. However, the resolved shear stresses arising from a homogeneous state of stress do not accord with such a slip arrangement except in the case of pairs of perpendicular faults. Where fault surfaces are non-planar, the directions of resolved shear stress in general give, according to the Wallace-Bott hypothesis, a set of slip directions of rigid fault blocks, which is generally kinematically incompatible. Finally, a simple model of a corrugated fault suggests that any anisotropy of the shear strength of the fault such as that arising from fault surface topography, can lead to a significant angular difference between the directions of maximum shear stress and the slip direction.These findings have relevance to the design of procedures used to estimate palaeostresses and the amount of data required for this type of analysis.

Surface Profile Analysis for Conformable Interfaces

2003 ◽  
Vol 125 (3) ◽  
pp. 624-627 ◽  
Author(s):  
Mark C. Malburg
Keyword(s):  
Contact Area ◽  
Load Distribution ◽  
Profile Analysis ◽  
Surface Profile ◽  
Solid Surfaces ◽  
Analysis Method ◽  
Uniform Load ◽  
Morphological Filtering ◽  
Novel Method

This paper presents a novel method for the analysis of solid surfaces in contact with a conformable component. These applications are common in many engine and hydraulic applications, wherein conformable seals, gaskets, bushings, etc. are employed to prevent unwanted flow across an interface or provide a uniform load distribution. The proposed analysis method employs a combination of meanline (m-system) filtering and envelope (e-system) or morphological filtering. Through this analysis, a simulation of contact area and the associated voids or gaps can be assessed.

Understanding receptor-mediated endocytosis of elastic nanoparticles through coarse grained molecular dynamic simulation

2018 ◽  
Vol 20 (24) ◽  
pp. 16372-16385 ◽  
Author(s):  
Zhiqiang Shen ◽  
Huilin Ye ◽  
Ying Li
Keyword(s):  
Molecular Dynamic Simulation ◽  
Molecular Dynamic ◽  
Dynamic Simulation ◽  
Contact Area ◽  
Late Stage ◽  
Early Stage ◽  
Coarse Grained ◽  
Large Energy ◽  
Receptor Mediated Endocytosis ◽  
Large Contact Area

The membrane wrapping of the soft nanoparticle (NP) is faster than that of the stiff one at the early stage, due to the NP deformation induced large contact area between the NP and membrane. However, because of the large energy penalties induced by the NP deformation, the membrane wrapping speed of soft NPs slows down during the late stage.

Nonlinear instabilities and control of drill-string stick-slip vibrations with consideration of state-dependent delay

2020 ◽  
Vol 473 ◽  
pp. 115235 ◽  
Author(s):  
Xie Zheng ◽  
Vipin Agarwal ◽  
Xianbo Liu ◽  
Balakumar Balachandran
Keyword(s):  
Drill String ◽  
Stick Slip ◽  
State Dependent ◽  
State Dependent Delay ◽  
And Control

Novel Gene-Transferring System Using a Laminin-DNA-Apatite Composite Layer

2007 ◽  
Vol 330-332 ◽  
pp. 1021-1025 ◽  
Author(s):  
Ayako Oyane ◽  
Hideo Tsurushima ◽  
Atsuo Ito
Keyword(s):  
Tissue Engineering ◽  
Gene Therapy ◽  
Surface Layer ◽  
Cell Adhesion ◽  
Contact Area ◽  
High Efficiency ◽  
Composite Layer ◽  
Ethylene Vinyl Alcohol ◽  
Large Contact Area ◽  
Present Gene

A laminin–DNA–apatite composite layer was successfully formed on the surface of an ethylene–vinyl alcohol copolymer. The immobilized DNA was transferred to the cells adhering onto the laminin–DNA–apatite composite layer more efficiently than those adhering onto a lamininfree DNA–apatite composite layer. It is considered that laminin immobilized in the surface layer enhances cell adhesion and spreading, and DNA locally released from the layer is effectively transferred into the adhering cells, taking advantage of the large contact area. The present gene transferring system, which shows high efficiency and safety, would be useful in gene therapy and tissue engineering.

scholarly journals Tremor during ice-stream stick slip

2016 ◽  
Vol 10 (1) ◽  
pp. 385-399 ◽  
Author(s):  
B. P. Lipovsky ◽  
E. M. Dunham
Keyword(s):  
Large Scale ◽  
Wait Time ◽  
Stick Slip ◽  
Repeating Earthquakes ◽  
Ice Surface ◽  
Ice Stream ◽  
State Dependent ◽  
State Evolution ◽  
Spectral Peaks ◽  
Balance Of Forces

Abstract. During the 200 km-scale stick slip of the Whillans Ice Plain (WIP), West Antarctica, seismic tremor episodes occur at the ice–bed interface. We interpret these tremor episodes as swarms of small repeating earthquakes. The earthquakes are evenly spaced in time, and this even spacing gives rise to spectral peaks at integer multiples of the recurrence frequency ∼ 10–20 Hz. We conduct numerical simulations of the tremor episodes that include the balance of forces acting on the fault, the evolution of rate- and state-dependent fault friction, and wave propagation from the fault patch to a seismometer located on the ice. The ice slides as an elastic block loaded by the push of the upstream ice, and so the simulated basal fault patch experiences a loading velocity equal to the velocity observed by GPS receivers on the surface of the WIP. By matching synthetic seismograms to observed seismograms, we infer fault patch area ∼ 10 m2, bed shear modulus ∼ 20 MPa, effective pressure ∼ 10 kPa, and frictional state evolution distance ∼ 1 μm. Large-scale slip events often occur twice daily, although skipped events have been increasing in frequency over the last decade. The amplitude of tremor (recorded by seismometers on the ice surface) is greater during the double wait time events that follow skipped events. The physical mechanism responsible for these elevated amplitudes may provide a window into near-future subglacial conditions and the processes that occur during ice-stream stagnation.

scholarly journals DESIGNING A SHAPED SEAT-PAN CUSHION TO IMPROVE POSTURAL (DIS)COMFORT REDUCING PRESSURE DISTRIBUTION AND INCREASING CONTACT AREA AT THE INTERFACE

2021 ◽  
Vol 1 ◽  
pp. 1113-1122
Author(s):  
Iolanda Fiorillo ◽  
Yu Song ◽  
Peter Vink ◽  
Alessandro Naddeo
Keyword(s):  
Pressure Distribution ◽  
Contact Area ◽  
Geometric Shape ◽  
Average Pressure ◽  
Health Issues ◽  
Two Factors ◽  
Physical Prototype ◽  
Large Contact Area ◽  
Prototype Design ◽  
Straightforward Approach

AbstractRemaining seated for extended periods increases the risk health issues and discomfort perception. Consequently, the seat-pan design is crucial and could be mainly influenced by two factors: pressure distribution and seat contour. For seat pan discomfort, the lower average pressure is accompanied by less discomfort. Moreover, a seat contour with a large contact area is correlated with more comfort. Thus, a shaped cushion had been accurately designed (Virtual Prototype) and realized (Physical Prototype) aiming to translate the pressure distribution due to interaction between seat and buttock in a geometric shape, suitable for the international population (including P5 females and P95 males). With this shape, the pressure should be more uniform and lower, the contact area at interface bigger, and the perceived comfort higher. Both Virtual and Physical Prototype design had been described in this paper through a repeatable and straightforward approach. Also, experiments had been performed to validate the hypothesis through a comparison with a standard flat cushion. Results showed the goal of the design had been reached: the shaped cushion scored less pressure distribution and higher contact area than the flat cushion.

710 Simulation of Stick-slip Motion of Serial Printer Caused by Surface Profile

2000 ◽  
Vol 005.2 (0) ◽  
pp. 219-220
Author(s):  
Tomoharu SHIMIZU ◽  
Michimasa UCHIDATE ◽  
Keiji KATANO ◽  
Akira IWABUCHI
Keyword(s):  
Surface Profile ◽  
Stick Slip ◽  
Stick Slip Motion ◽  
Slip Motion

Numerical analysis of onset of stick-slip motion by rate- and state-dependent friction model

2016 ◽  
Vol 2016 (0) ◽  
pp. OS03-04
Author(s):  
Takeru MATSUURA ◽  
Tomoki SANO ◽  
Shingo OZAKI
Keyword(s):  
Numerical Analysis ◽  
Friction Model ◽  
Stick Slip ◽  
State Dependent ◽  
Stick Slip Motion ◽  
Slip Motion
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