scholarly journals Evolution of shear fabric in granular fault gouge from stable sliding to stick slip and implications for fault slip mode

Geology ◽  
2017 ◽  
pp. G39033.1 ◽  
Author(s):  
M.M. Scuderi ◽  
C. Collettini ◽  
C. Viti ◽  
E. Tinti ◽  
C. Marone
Keyword(s):  
Fault Slip ◽  
Fault Gouge ◽  
Slip Mode ◽  
Stick Slip ◽  
Stable Sliding

Stress triggering and the mechanics of fault slip behavior

2020 ◽  
Author(s):  
Marco Maria Scuderi ◽  
Cristiano Collettini
Keyword(s):  
Stress Field ◽  
Normal Stress ◽  
Stability Boundary ◽  
Fault Slip ◽  
Fault Gouge ◽  
Recurrence Time ◽  
Slow Slip ◽  
Stick Slip ◽  
Slow Slip Events ◽  
Stress Changes

<p>Dynamic changes in the stress field during the seismic cycle of tectonic faults can control frictional stability and the mode of fault slip. Small perturbation in the stress field, like those produced by tidal stresses can influence the evolution of frictional strength and fault stability with the potential of triggering a variety of slip behaviors. However, an open question that remains still poorly understood is how amplitude and frequency of stress changes influence the triggering of an instability and the associated slip behavior, i.e. slow or fast slip.</p><p>Here we reproduce in the laboratory the spectrum of fault slip behaviors, from slow-slip to dynamic stick-slip, by matching the critical fault rheologic stiffness (kc) with the surrounding stiffness (k). We investigate the influence of normal stress variations on the slip style of a quartz rich fault gouge at the stability boundary, i.e. k/kc slightly less than one, by adopting two techniques: 1) instantaneous step-like changes and 2) sinusoidal variations in normal stress. For the latter case, modulations of normal stress were chosen to have amplitudes greater, less or equal to the typical stress drop observed during unperturbed experiments. Also, the period was varied to be greater, less or equal to the typical recurrence time of laboratory slow-slip events. During the experiments, we continuously record ultrasonic wave velocity to monitor the microphysical state of the fault. We find that frictional stability is profoundly affected by variation in normal stress giving rise to a variety of slip behaviors. Furthermore, during strain accumulation and fabric development, changes in normal stress permanently influence the microphysical state of the fault gouge increasing kc and producing a switch from slow to fast stick-slip. Our results indicate that perturbations in the stress state can trigger a variety of slip behaviors along the same fault patch. These results have important implications for the formulation of constitutive laws in the framework of rate- and state- friction, highlighting the necessity to account for the microphysical state of the fault in order to improve our understanding of frictional stability.</p>

scholarly journals Effects of Particle Size on Fault Gouge Frictional Characteristics and Associated Acoustic Emission

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yang Liu ◽  
Cai-Ping Lu ◽  
Tong-bin Zhao ◽  
Heng Zhang
Keyword(s):  
Particle Size ◽  
Acoustic Emission ◽  
Surface Defects ◽  
Dynamic Instability ◽  
Shear Velocity ◽  
Fault Gouge ◽  
Stick Slip ◽  
Compaction Rate ◽  
Fault Strength ◽  
Stable Sliding

Our experimental work was designed to explore the particle size effect of simulated fault gouge on slip characteristics by the conventional double-direct shear friction configuration combined with acoustic emission (AE). The following conclusions were drawn: (1) smaller particles allow for an initially higher compaction rate at a higher speed and longer duration for force chain formation and destruction. The larger the particle size is, the higher the slipping displacement rate is; (2) the smaller the particle size is, the larger the friction coefficient is, and thus the higher the fault strength is. In addition, the larger the shear velocity is, the higher the fault strength is; (3) the smaller the particle size is, the higher the shear stress drop generated by the stick-slip is, and the stronger the dynamic slip intensity for a stick-slip period is; and (4) surface defects of forcing blocks possibly help to embed foregoing “stability” and “stable sliding” into the normal stick-slip stage. Especially, the “stable sliding” is possibly related to formation of stubborn force chains. These findings may shed some insights into further clarification of slipping characteristics and discrimination of precursory signs of fault dynamic instability with different-sized gouge particles.

Structures developed in fault gouge during stable sliding and stick-slip

1978 ◽  
Vol 44 (1-4) ◽  
pp. 161-171 ◽  
Author(s):  
J. Byerlee ◽  
V. Mjachkin ◽  
R. Summers ◽  
O. Voevoda
Keyword(s):  
Fault Gouge ◽  
Stick Slip ◽  
Stable Sliding

Large-Scale Evaluation of Constrained Bearing Elements Made of Thermosetting Polyester Resin and Polyester Fabric Reinforcement

2006 ◽  
Vol 128 (4) ◽  
pp. 681-696 ◽  
Author(s):  
P. Samyn ◽  
W. Van Paepegem ◽  
J. S. Leendertz ◽  
A. Gerber ◽  
L. Van Schepdael ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Large Scale ◽  
Elastic Recovery ◽  
Small Scale ◽  
Practical Implementation ◽  
Fiber Failure ◽  
Stick Slip ◽  
Composite Surface ◽  
Pull Out ◽  
Stable Sliding

Polymer composites are increasingly used as sliding materials for high-loaded bearings, however, their tribological characteristics are most commonly determined from small-scale laboratory tests. The static strength and dynamic coefficients of friction for polyester/polyester composite elements are presently studied on large-scale test equipment for determination of its bearing capacity and failure mechanisms under overload conditions. Original test samples have a diameter of 250 mm and thickness of 40 mm, corresponding to the practical implementation in the sliding surfaces of a ball-joint, and are tested at various scales for simulation of edge effects and repeatability of test results. Static tests reveal complete elastic recovery after loading to 120 MPa, plastic deformation after loading at 150 MPa and overload at 200 MPa. This makes present composite favorable for use under high loads, compared to, e.g., glass-fibre reinforced materials. Sliding tests indicate stick-slip for pure bulk composites and more stable sliding when PTFE lubricants are added. Dynamic overload occurs above 120 MPa due to an expansion of the nonconstrained top surface. A molybdenum-disulphide coating on the steel counterface is an effective lubricant for lower dynamic friction, as it favorably impregnates the composite sliding surface, while it is not effective at high loads as the coating is removed after sliding and high initial static friction is observed. Also a zinc phosphate thermoplastic coating cannot be applied to the counterface as it adheres strongly to the composite surface with consequently high initial friction and coating wear. Most stable sliding is observed against steel counterfaces, with progressive formation of a lubricating transfer film at higher loads due to exposure of PTFE lubricant. Composite wear mechanisms are mainly governed by thermal degradation of the thermosetting matrix (max. 162°C) with shear and particle detachment by the brittle nature of polyester rather than plastic deformation. The formation of a sliding film protects against fiber failure up to 150 MPa, while overload results in interlaminar shear, debonding, and ductile fiber pull-out.

Study of a piezo-electric actuated vibratory micro-robot in stick-slip mode and investigating the design parameters

2017 ◽  
Vol 89 (3) ◽  
pp. 1927-1948 ◽  
Author(s):  
Hadi Jalili ◽  
Hassan Salarieh ◽  
Gholamreza Vossoughi
Keyword(s):  
Design Parameters ◽  
Slip Mode ◽  
Stick Slip ◽  
Micro Robot ◽  
Piezo Electric
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