The Development of Kink Bands in Brittle Anisotropic Rock

1969 ◽  
pp. 453-494 ◽  
Author(s):  
Fred A. Donath
Keyword(s):  
Anisotropic Rock ◽  
Kink Bands

Cosserat Modeling of Size Effects in Crystalline Solids

2000 ◽  
Vol 653 ◽  
Author(s):  
Samuel Forest
Keyword(s):  
Stress State ◽  
Size Effects ◽  
Elastic Inclusion ◽  
Characteristic Size ◽  
Infinite Matrix ◽  
Crystalline Solids ◽  
Generalized Continua ◽  
Absolute Size ◽  
Kink Bands ◽  
The Matrix

AbstractThe mechanics of generalized continua provides an efficient way of introducing intrinsic length scales into continuum models of materials. A Cosserat framework is presented here to descrine the mechanical behavior of crystalline solids. The first application deals with the problem of the stress field at a crak tip in Cosserat single crystals. It is shown that the strain localization patterns developping at the crack tip differ from the classical picture : the Cosserat continuum acts as a bifurcation mode selector, whereby kink bands arising in the classical framework disappear in generalized single crystal plasticity. The problem of a Cosserat elastic inclusion embedded in an infinite matrix is then considered to show that the stress state inside the inclusion depends on its absolute size lc. Two saturation regimes are observed : when the size R of the inclusion is much larger than a characteristic size of the medium, the classical Eshelby solution is recovered. When R is much small than the inclusion, a much higher stress is reached (for an inclusion stiffer than the matrix) that does not depend on the size any more. There is a transition regime for which the stress state is not homogeneous inside the inclusion. Similar regimes are obtained in the study of grain size effects in polycrystalline aggregates of Cosserat grains.

scholarly journals Heat Aged Tensile Strength Retention of Poly (p-phenylene terephthalamide) Sewing Thread

2008 ◽  
Vol 3 (4) ◽  
pp. 155892500800300 ◽  
Author(s):  
Walter R. Hall ◽  
Warren F. Knoff
Keyword(s):  
Hydrolytic Degradation ◽  
Oxidative Degradation ◽  
Thermal Exposure ◽  
Strength Loss ◽  
Degradation Process ◽  
Downstream Processing ◽  
Kink Bands ◽  
Sewing Thread ◽  
Continuous Filament ◽  
Strength Retention

The strength retention after exposure to elevated temperature in air of continuous filament and staple spun PPTA sewing thread and the precursor yarns was determined. For both types, the process of converting the greige yarn to thread reduced the amount of strength retained after thermal exposure. The continuous filament products retained more strength than the staple products. The data was fitted to a kinetic rate model in which two strength loss processes occurred. The first process occurred within about the first 5 minutes of thermal exposure and is hypothesized to be hydrolytic degradation. The estimated secondary degradation process activation energy suggests this to be thermo-oxidative degradation. Optical microscopy of filaments indicates a higher level of kink banding and other damage in continuous filament versus staple products and in finished thread versus the precursor yarns. The kink bands and damage are believed to be caused by the staple manufacturing process and the downstream processing of precursor yarn to finished sewing thread. The kink bands and damage are hypothesized to be responsible for the differences in strength retention.

Effect of strain rate, off-axis loading and high-velocity impact damage on the compressive strength of C/SiC composite

2018 ◽  
Vol 53 (4) ◽  
pp. 535-546 ◽  
Author(s):  
M Altaf ◽  
S Singh ◽  
VV Bhanu Prasad ◽  
Manish Patel
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
High Velocity ◽  
Impact Damage ◽  
The Other ◽  
High Velocity Impact ◽  
Fibre Bundles ◽  
Velocity Impact ◽  
Kink Bands ◽  
Other Hand

The compressive strength of C/SiC composite at different strain rates, off-axis orientations and after high-velocity impact was studied. The compressive strength was found to be 137 ± 23, 130 ± 46 and 162 ± 33 MPa at a strain rate of 3.3 × 10−5, 3.3 × 10−3, 3.3 × 10−3 s−1, respectively. On the other hand, the compressive strength was found to be 130 ± 46, 99 ± 23 and 87 ± 9 MPa for 0°/90°, 30°/60° and 45°/45° fibre orientations to loading direction, respectively. After high-velocity impact, the residual compressive strength of C/SiC composite was found to be 58 ± 26, 44 ± 18 and 36 ± 3.5 MPa after impact with 100, 150 and 190 m/s, respectively. The formation of kink bands in fibre bundles was found to be dominant micro-mechanism for compressive failure of C/SiC composite for 0°/90° orientation. On the other hand, delamination and the fibre bundles rotation were found to be the dominant mechanism for off-axis failure of composite.

Dynamics of Kink Bands in Layered Liquids:  Theory and in Situ SAXS Experiments on a Block Copolymer Melt

2001 ◽  
Vol 34 (22) ◽  
pp. 7858-7867 ◽  
Author(s):  
Lei Qiao ◽  
Karen I. Winey ◽  
David C. Morse
Keyword(s):  
Block Copolymer ◽  
Kink Bands

Structural analysis of Bic fault, a thrust-related strike-slip fault of the external domain of the Taconic Orogen, Appalachians, Quebec, and metallogenic implications

1991 ◽  
Vol 28 (5) ◽  
pp. 788-799 ◽  
Author(s):  
P. Rhéaume ◽  
K. Schrijver
Keyword(s):  
Strike Slip ◽  
Strike Slip Fault ◽  
Thrust Sheet ◽  
Kink Bands ◽  
Strain Ellipsoid ◽  
Adjacent Part ◽  
External Domain ◽  
Dextral Strike Slip Fault ◽  
Thrust Sheets ◽  
Stage 1

The Bic fault is exposed along the shoreline of the St. Lawrence River, 21 km southwest of Rimouski, for 210 m at Cap à l'Orignal and for 100 m at Cap Enragé. The fault brings in contact two major thrust sheets, the Des Seigneuries and the Des Iles, Cambrian lithologies of the former overlying Ordovician rocks of the latter. In the Taconic Orogen, such contacts are normally thrust faults, but the Bic fault is a dextral strike-slip fault, striking east–west and dipping southward. A study of a narrow zone straddling the fault and an adjacent part of the Des Seigneuries thrust sheet has led to the recognition of four successive stages of deformation, all compatible with a northeast–southwest-trending strain ellipsoid. The two first stages are most important: stage 1 brought about regional folding and faulting, whereas stage 2 was characterized by the development of various structural elements (C–S fabrics, stretching lineation, Riedel shears, and kink bands) exclusive to the fault zone. We infer that (i) in the study area, the Bic fault constituted a lateral ramp along which the Des Seigneuries thrust sheet slid horizontally westward; and (ii) emplacement of Ba–Pb–Zn deposits took place slightly after this movement, probably during regional uplift of the orogen in Late Ordovician to Early Silurian time. The latter hypothesis tends to be corroborated by model lead ages of galena in two deposits.

scholarly journals Back analysis for circular or elliptical tunnel in isotropic and anisotropic rock medium based on exact elastic solutions.

1991 ◽  
pp. 1-8
Author(s):  
Ken-ichi HIRASIMA ◽  
Tetsutaro KAWAKAMI ◽  
Toshio FUJIWARA ◽  
Yukio YAMASHITA
Keyword(s):  
Back Analysis ◽  
Anisotropic Rock
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