A study of the large strain deformation and failure behaviour of mixed biopolymer gels via in situ ESEM

Establishment of a relationship between the shear wave velocity (Vs) and other geotechnical parameters of rockfill soils at large strains (oedometer modulus, Moedo, tangent modulus, Et) is considered a significant step towards more precise modelling of earth-structure deformation behaviour. In this study, four samples of different gradations, reconstituted from the rockfill materials used in the construction of the Romaine-2 dam, were experimented to correlate the small strain to large strain moduli. Development of Moedo and Vs with consolidation was measured in the laboratory using the piezoelectric ring-actuator technique (P-RAT) incorporated in a large oedometer. Therefore, a correlation between Moedo and small strain shear modulus Go was proposed. Moreover, numerical simulations were performed based on the Duncan-Chang hyperbolic model to correlate the Vs to Duncan-Chang initial modulus(Ei). Based on the experimental and numerical data, a relation between Ei and Vs of the tested rockfill has been established. Verification studies were also carried out on in-situ measurements during Romaine-2 dam construction, proofing the ability of the proposed relationships to predict Ei related to the minor principal stress (σ3) from in-situ Vs measurement. The proposed correlations could help the geotechnical designers to estimate accurately the deformation of rockfill materials from in-situ Vs measurement.

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Post-peak deformation and failure behaviour of Jinping marble under true triaxial stresses

Engineering Geology ◽

10.1016/j.enggeo.2019.105444 ◽

2020 ◽

Vol 265 ◽

pp. 105444

Author(s):

Zhi Zheng ◽

Xia-Ting Feng ◽

Cheng-Xiang Yang ◽

Xi-Wei Zhang ◽

Shao-Jun Li ◽

...

Keyword(s):

Deformation And Failure ◽

True Triaxial ◽

Failure Behaviour ◽

Triaxial Stresses ◽

Jinping Marble

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Severity of contraction-induced injury is affected by velocity only during stretches of large strain

Journal of Applied Physiology ◽

10.1152/jappl.2001.91.2.661 ◽

2001 ◽

Vol 91 (2) ◽

pp. 661-666 ◽

Cited By ~ 53

Author(s):

Susan V. Brooks ◽

John A. Faulkner

Keyword(s):

Null Hypothesis ◽

Isometric Force ◽

Large Strain ◽

Minor Role ◽

Average Force ◽

Significant Relationships ◽

Severity Of Injury ◽

Work Input ◽

A Minor

Our purpose was to investigate the effect of velocity of stretch on contraction-induced injury to whole skeletal muscles. Single stretches provide an effective method for studying factors that initiate contraction-induced injury. We tested the null hypothesis that the severity of injury is not dependent on the velocity of the stretch. From the plateau of maximum isometric contractions, extensor digitorum longus muscles of mice were administered single stretches in situ of 30–50% strain relative to muscle fiber length ( L f) at rates of 1–16 L f/s. The magnitude of injury was represented by the isometric force deficit 1–10 min after the stretch. Although the null hypothesis was not supported because the force deficit was affected by velocity ( r 2= 0.09), the effect was relatively weak and was not significant except at the largest strain. Velocity had no effect on peak or average force or work input, factors established to have significant relationships with the force deficit. Velocity may play a minor role in contraction-induced injury, but its importance is negligible relative to that of strain.

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In situ TEM Straining of Nanograined Al Films Strengthened with Al2O3 Nanoparticles

MRS Proceedings ◽

10.1557/proc-1262-v01-04 ◽

2010 ◽

Vol 1262 ◽

Author(s):

Khalid Hattar ◽

Blythe G. Clark ◽

James A Knapp ◽

David M Follstaedt ◽

I. M. Robertson

Keyword(s):

In Situ Tem ◽

Al2o3 Nanoparticles ◽

Particle Sizes ◽

Free Standing ◽

Active Deformation ◽

Deformation And Failure ◽

Annealing Conditions ◽

Thermal Histories ◽

Initial Results

AbstractGrowing interest in nanomaterials has raised many questions regarding the operating mechanisms active during the deformation and failure of nanoscale materials. To address this, a simple, effective in situ TEM straining technique was developed that provides direct detailed observations of the active deformation mechanisms at a length scale relevant to most nanomaterials. The capabilities of this new straining structure are highlighted with initial results in pulsed laser deposited (PLD) Al-Al2O3 thin films of uniform thickness. The Al-Al2O3 system was chosen for investigation, as the grain size can be tailored via deposition and annealing conditions and the active mechanisms in the binary system can be compared to previous studies in PLD Ni and evaporated Al films. PLD Al-Al2O3 free-standing films of various oxide concentrations and different thermal histories were produced and characterized in terms of average grain and particle sizes. Preliminary in situ TEM straining experiments show intergranular failure for films with 5 vol% Al2O3. Further work is in progress to explore and understand the active deformation and failure mechanisms, as well as the dependence of mechanisms on processing routes.

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Analytical Solution of Tunnel Surrounding Rock for Stress and Displacement Based on Lade–Duncan Criterion

Advances in Civil Engineering ◽

10.1155/2018/5363658 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

MingZheng Zhu ◽

Yugui Yang ◽

Feng Gao ◽

Juan Liu

Keyword(s):

Internal Friction ◽

Plastic Zone ◽

Yield Criterion ◽

Surrounding Rock ◽

Rock Stress ◽

Deformation And Failure ◽

Displacement Based ◽

The Stability ◽

Coulomb Criterion

The deformation and failure of tunnel surrounding rock is the result of tunnel excavation disturbance and rock stress release. When the local stress of surrounding rock exceeds the elastic limit of rock mass, the plastic analysis of surrounding rock must be carried out to judge the stability of tunnel. In this study, the Lade–Duncan yield criterion is used to calculate the analytic solutions for the surrounding rock in a tunnel, and the radius and displacement of the plastic zone are deduced using an equilibrium equation. The plastic zone radius and displacement based on Lade–Duncan criterion and Mohr–Coulomb criterion were compared by using single-factor analysis method under the different internal friction angles, in situ stresses, and support resistances. The results show that the solutions of the radius and displacement of plastic zone calculated by the Lade–Duncan criterion are close to those of Mohr–Coulomb criterion under the high internal friction angle and support resistance or low in situ rock stress; however, the radius and displacement of the plastic zone calculated by the Lade–Duncan criterion are larger under normal circumstances, and the Lade–Duncan criterion is more applicable to the stability analysis of the surrounding rock in a tunnel.

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Low-Temperature In Situ Large-Strain Plasticity of Silicon Nanowires

Advanced Materials ◽

10.1002/adma.200602705 ◽

2007 ◽

Vol 19 (16) ◽

pp. 2112-2118 ◽

Cited By ~ 251

Author(s):

X. D. Han ◽

K. Zheng ◽

Y. F. Zhang ◽

X. N. Zhang ◽

Z. Zhang ◽

...

Keyword(s):

Low Temperature ◽

Silicon Nanowires ◽

Large Strain ◽

Strain Plasticity ◽

Large Strain Plasticity

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Vocal Fold Tissue Failure: Preliminary Data and Constitutive Modeling†

Journal of Biomechanical Engineering ◽

10.1115/1.1785804 ◽

2004 ◽

Vol 126 (4) ◽

pp. 466-474 ◽

Cited By ~ 12

Author(s):

Roger W. Chan

Keyword(s):

Preliminary Data ◽

Vocal Fold ◽

Large Strain ◽

Deformation And Failure ◽

Rate Dependent ◽

Nonlinear Stress ◽

Tissue Specimens ◽

Dependent Failure ◽

Tissue Stresses

In human voice production (phonation), linear small-amplitude vocal fold oscillation occurs only under restricted conditions. Physiologically, phonation more often involves large-amplitude oscillation associated with tissue stresses and strains beyond their linear viscoelastic limits, particularly in the lamina propria extracellular matrix (ECM). This study reports some preliminary measurements of tissue deformation and failure response of the vocal fold ECM under large-strain shear. The primary goal was to formulate and test a novel constitutive model for vocal fold tissue failure, based on a standard-linear cohesive-zone (SL-CZ) approach. Tissue specimens of the sheep vocal fold mucosa were subjected to torsional deformation in vitro, at constant strain rates corresponding to twist rates of 0.01, 0.1, and 1.0 rad/s. The vocal fold ECM demonstrated nonlinear stress-strain and rate-dependent failure response with a failure strain as low as 0.40 rad. A finite-element implementation of the SL-CZ model was capable of capturing the rate dependence in these preliminary data, demonstrating the model’s potential for describing tissue failure. Further studies with additional tissue specimens and model improvements are needed to better understand vocal fold tissue failure.

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