Size Dependent Micro-Stress-Field of Fibers in Eutectic Ceramic Rod

2010 ◽  
Vol 168-170 ◽  
pp. 226-229
Author(s):  
Hai Xing Lu ◽  
Xie Quan Liu ◽  
Xin Hua Ni ◽  
Tao Sun ◽  
Bao Feng Li
Keyword(s):  
Stress Field ◽  
Local Stress ◽  
Apparent Size ◽  
Average Strain ◽  
Size Dependent ◽  
Three Phase ◽  
Stress Boundary Condition ◽  
Stress Boundary ◽  
Remote Stress ◽  
Local Stress Field

Considering the interaction between fiber-inclusion and strong constraining interphase, forth-phase model is suggested to determine the local stress field distribution of three-phase element in eutectic ceramic rod. On the basis of the volumetric average strain, the effective compliance tensor increment of eutectic ceramic rod is obtained. The remote stress boundary condition of the eutectic ceramic rod is accounted for getting the micro stress field of fibers in eutectic ceramic rod. The results show the micro stress field of the fiber-inclusion in eutectic ceramic rod is associated with the stiffness and the volume fractions of each component in eutectic ceramic rod, the shape of interphase and fiber. The micro stress field has apparent size effect: three direction stresses increase with the diameter of fiber- inclusion.

Micro-Stress-Field of Lamellar Inclusion in Eutectic Composite Ceramic

2012 ◽  
Vol 204-208 ◽  
pp. 4433-4436 ◽  
Author(s):  
Xie Quan Liu ◽  
Xin Hua Ni ◽  
Jing Zhang ◽  
Xiang Feng Meng
Keyword(s):  
Stress Field ◽  
Composite Ceramic ◽  
Apparent Size ◽  
Phase Cell ◽  
Ceramic Analysis ◽  
Eutectic Composite ◽  
Three Phase ◽  
Stress Boundary Condition ◽  
Stress Boundary ◽  
Remote Stress

According to the interaction between lamellar inclusion and interphase, forth-phase model is suggested to determine the micro-stress-field distribution of three-phase cell in eutectic composite ceramic. On the basis of the volumetric average strain, the effective compliance tensor increment of eutectic composite ceramic is obtained. The remote stress boundary condition of the eutectic composite ceramic is accounted for getting the micro-stress-field of lamellar inclusion in eutectic composite ceramic. Analysis shows that the micro-stress-field of the lamellar inclusion in eutectic composite ceramic is associated with the stiffness and the volume fractions of each component in eutectic composite ceramic, the shape of interphase and lamellar inclusion. The-micro-stress field has apparent size effect: three direction stresses increase with the thickness of lamellar inclusion.

Interaction between two nanoscale elliptical holes with surface tension

2018 ◽  
Vol 24 (5) ◽  
pp. 1556-1566 ◽  
Author(s):  
Shuang Wang ◽  
Cun-Fa Gao ◽  
Zeng-Tao Chen
Keyword(s):  
Surface Tension ◽  
Stress Field ◽  
Hoop Stress ◽  
Elliptical Hole ◽  
Integral Form ◽  
Maximum Hoop Stress ◽  
Stress Boundary Condition ◽  
Elliptical Holes ◽  
Basic Equations ◽  
Stress Boundary

In this paper, the plane problem of two elliptical nanoscale holes with surface tension is investigated. Firstly, the basic equations are given via the complex variable methods. Then, the stress boundary condition caused by surface tension is derived through the integral-form Gurtin–Murdoch model. The problem is finally solved by the conformal mapping along with the series expansion methods. The results show that the stress field decreases as the two holes become further away from each other. When the distance between the two holes is more than three times the sum of their sizes, the interaction between the two holes can be neglected. In addition, the stress field is greatly influenced by the orientation, aspect ratio and size of the holes. The positions of the maximum hoop stress are also discussed. When the two elliptical holes are put close horizontally, the hoop stress around one hole usually obtain its maximum at the endpoint close to the other hole. However, if one elliptical hole is not horizontal, the hoop stress around it will no longer attain its maximum at the endpoints. Another exception is that when one elliptical hole becomes larger, the hoop stress around the smaller hole would tend to achieve a local minimum at the endpoint close to the larger hole.

scholarly journals Activation of optimally and unfavourably oriented faults in a uniform local stress field during the 2011 Prague, Oklahoma, sequence

2020 ◽  
Vol 222 (1) ◽  
pp. 153-168 ◽  
Author(s):  
Elizabeth S Cochran ◽  
Robert J Skoumal ◽  
Devin McPhillips ◽  
Zachary E Ross ◽  
Katie M Keranen
Keyword(s):  
Stress Field ◽  
Compressive Stress ◽  
Local Stress ◽  
Wastewater Disposal ◽  
Principal Compressive Stress ◽  
Vertical Fault ◽  
Major Fault ◽  
Pressure Changes ◽  
Earthquake Sequences ◽  
Local Stress Field

SUMMARY The orientations of faults activated relative to the local principal stress directions can provide insights into the role of pore pressure changes in induced earthquake sequences. Here, we examine the 2011 M 5.7 Prague earthquake sequence that was induced by nearby wastewater disposal. We estimate the local principal compressive stress direction near the rupture as inferred from shear wave splitting measurements at spatial resolutions as small as 750 m. We find that the dominant azimuth observed is parallel to previous estimates of the regional compressive stress with some secondary azimuths oriented subparallel to the strike of the major fault structures. From an extended catalogue, we map ten distinct fault segments activated during the sequence that exhibit a wide array of orientations. We assess whether the five near-vertical fault planes are optimally oriented to fail in the determined stress field. We find that only two of the fault planes, including the M   5.7 main shock fault, are optimally oriented. Both the M 4.8 foreshock and M   4.8 aftershock occur on fault planes that deviate 20–29° from the optimal orientation for slip. Our results confirm that induced event sequences can occur on faults not optimally oriented for failure in the local stress field. The results suggest elevated pore fluid pressures likely induced failure along several of the faults activated in the 2011 Prague sequence.

A simplified method to predict the local stress field and N-SIF of V-shaped notch

2020 ◽  
Vol 234 ◽  
pp. 107096 ◽  
Author(s):  
Wei Shen ◽  
Guiming Liang ◽  
Chunmei Li ◽  
Enqian Liu
Keyword(s):  
Stress Field ◽  
Local Stress ◽  
Simplified Method ◽  
Local Stress Field

Seismic anisotropy time variations at Mt Etna

2019 ◽  
Vol 220 (1) ◽  
pp. 450-460
Author(s):  
Lucia Nardone ◽  
Francesca Bianco ◽  
Lucia Zaccarelli ◽  
Domenico Patanè
Keyword(s):  
Time Delay ◽  
Stress Field ◽  
Shear Wave ◽  
Local Stress ◽  
Temporal Variations ◽  
Fast Wave ◽  
Polarization Direction ◽  
Stress Changes ◽  
Mt Etna ◽  
Local Stress Field

SUMMARY The aim of this paper is to study the temporal variations in the seismic wavefield associated with the stress changes in the dynamic features of the Mt Etna volcanic activity. We used shear wave splitting analysis on a huge data set of local earthquakes, in order to identify changes of the local stress field at Mt Etna during the time interval from 2006 to 2011. This analysis allows us to obtain two parameters: the polarization direction of the fast shear wave (φ) and the time delay of the slow shear wave (Td,time delay between the split shear waves). Orientation of φ generally provides information about the anisotropic symmetry and stress direction whereas Td provide information about the average crack density along the ray path. Based on our findings it is possible to divide Etna Volcano in three different sectors, each one distinguished by typical fast wave polarization direction. We find that the western part of the volcano is controlled by the regional tectonic stress field having a NS and EW directions. Instead, the eastern part of the volcano is mainly controlled by the local volcanic stress, particularly an EW local stress field in the NE sector (Pernicana), and a quasi NS local stress field in the SE sector (Mascalucia, Timpe), where previous studies evidenced: (i) some low-Qp anomaly regions between 0 and about 6 km depth, probably associated with high pore pressure and the intense faulting and (ii) by magnetotelluric surveys, several high conductivity zones, up to 8 km depth, related to a diffuse presence of hydrothermal activity and fluid circulation. Temporal variations in time delay, mostly before the 2008–2009 lateral eruption, can be interpreted as stress accumulation increase with a consequent release of stress due to coalescing of microcracks in the conduit for the eruption of magma.

Modeling the local stress field and kinematics of the San Andreas fault system

1979 ◽  
Vol 52 (1-4) ◽  
pp. 647-663 ◽  
Author(s):  
D.N. Osokina ◽  
A.A. Nikonov ◽  
N.Yu. Tsvetkova
Keyword(s):  
Stress Field ◽  
San Andreas Fault ◽  
Local Stress ◽  
Fault System ◽  
San Andreas ◽  
San Andreas Fault System ◽  
Local Stress Field

Screw Dislocations in a Three-Phase Composite Cylinder Model With Interface Stress

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Q. H. Fang ◽  
Y. W. Liu ◽  
P. H. Wen
Keyword(s):  
Boundary Condition ◽  
Classical Case ◽  
Interface Stress ◽  
Composite Cylinder ◽  
Screw Dislocations ◽  
Three Phase ◽  
Cylinder Model ◽  
The Matrix ◽  
Stress Boundary Condition ◽  
Stress Boundary

A three-phase composite cylinder model is utilized to study the interaction between screw dislocations and nanoscale inclusions. The stress boundary condition at the interface between nanoscale inclusion and the matrix is modified by incorporating surface/interface stress. The explicit solution to this problem is derived by means of the complex variable method. The explicit expressions of image forces exerted on screw dislocations are obtained. The mobility and the equilibrium positions of the dislocation near one of the inclusions are discussed. The results show that, compared to the classical solution (without interface stress), more equilibrium positions of the screw dislocation may be available when the dislocation is close to the nanoscale inclusion due to consider interface stress. Also, the mobility of the dislocation in the matrix will become more complex than the classical case.

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