scholarly journals Experimental framework for evaluating the mechanical behavior of dry and wet crushable granular materials based on the particle breakage ratio

2015 ◽  
Vol 52 (5) ◽  
pp. 587-598 ◽  
Author(s):  
Carlos Ovalle ◽  
Christophe Dano ◽  
Pierre-Yves Hicher ◽  
Mónica Cisternas
Keyword(s):  
Mechanical Behavior ◽  
Water Content ◽  
Granular Materials ◽  
Mechanical Response ◽  
Empirical Relation ◽  
Initial Density ◽  
Constitutive Models ◽  
Stress Path ◽  
Particle Crushing ◽  
Effect Of Water

It has been widely shown that particle crushing increases the compressibility of granular materials. For a particular crushable material and given test conditions, an empirical relation can be established between the breakage ratio and the plastic work. Along these lines, constitutive models have been developed based on the effect of grading evolution during crushing. In parallel, due to corrosive attacks of the humid environment at the tip of microcracks within solid grains, the mechanical behavior of crushable granular materials depends also on the water content: the higher the material humidity, the higher the particle crushing. However, the experimental data on the relation between loading–wetting conditions and the breakage ratio are still quite scarce. In this paper, we present experimental results on crushable sand to study the effect of flooding under isotropic, oedometric, and triaxial stress paths. The main objective of this study is to obtain a consistent framework for the effect of water based on the breakage ratio. Our results have shown that, for a given initial density and stress path, the dry material after flooding reaches the equivalent behavior of the initially wetted material in terms of compression curve, particle crushing, and creep compressibility index, regardless of the point of flooding. Moreover, the relation between the breakage ratio and the final void ratio is unique and depends neither on the stress path, the water content, the point of flooding, nor the loading condition (time of creep or relaxation), but exclusively on the initial density and on intrinsic parameters. These findings could improve the prediction of the effect of water and time on the mechanical response of crushable granular materials through constitutive models based on grading evolution.

scholarly journals Experimental Study on the Mechanical Behavior of Yunnan Limestone in Natural and Saturated States

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Xutao Zhang ◽  
Mingyang Ren ◽  
Zhaobo Meng ◽  
Baoliang Zhang ◽  
Jinglong Li
Keyword(s):  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Water Content ◽  
Failure Modes ◽  
Shear Failure ◽  
Mechanical Response ◽  
Deformation Modulus ◽  
Confining Pressure ◽  
Hyperbolic Function ◽  
Test Results

Rock material is a kind of mineral assemblage with complex structural heterogeneity, whose mechanical behavior is strongly affected by water or moisture content. In this work, we carried out a series of laboratory tests to investigate the mechanical response (e.g., deformation, strength, and failure characteristics) of Yunnan limestone in natural and saturated states. Our test results show that (1) after saturation, the stiffness and strength of Yunnan limestone degenerate considerably. Compared with the natural condition, the elastic modulus, deformation modulus, and tensile modulus decrease by about 30% on average, and uniaxial compressive strength and tensile strength also decrease by about 15% and 20%, respectively. While Poisson’s ratio is less affected by water content, it can be regarded as a constant; (2) the elastic modulus and deformation modulus of Yunnan limestone are significantly affected by confining pressure, and the relationship between them and confining pressure satisfies the law of hyperbolic function; (3) the peak strength envelope of Yunnan limestone has significant nonlinear characteristics, which can be well described by generalized Hoek-Brown strength criterion. However, the generalized Hoek-Brown criterion does not apply to the residual strength, which shows a linearly increasing trend with the increasing confining pressure; (4) the failure modes of Yunnan limestone are significantly dependent on confining pressure but insensitive to water content. With the increasing confining pressure, the failure modes of Yunnan limestone transform from splitting failure, tension-shear mixed failure, single inclined plane shear failure to Y-shaped or X-shaped conjugated shear failure. The test results can provide important experimental data for the establishment of the constitutive model of Yunnan limestone, which will contribute to obtain more reliable results for stability assessment of Xianglu Mountain Tunnel.

Skin mechanical properties and modeling: A review

2018 ◽  
Vol 232 (4) ◽  
pp. 323-343 ◽  
Author(s):  
Hamed Joodaki ◽  
Matthew B Panzer
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Mechanical Response ◽  
Constitutive Models ◽  
Experimental Methods ◽  
Loading History ◽  
Aging Effects ◽  
Failure Properties ◽  
Observed Behavior

The mechanical properties of the skin are important for various applications. Numerous tests have been conducted to characterize the mechanical behavior of this tissue, and this article presents a review on different experimental methods used. A discussion on the general mechanical behavior of the skin, including nonlinearity, viscoelasticity, anisotropy, loading history dependency, failure properties, and aging effects, is presented. Finally, commonly used constitutive models for simulating the mechanical response of skin are discussed in the context of representing the empirically observed behavior.

Mechanical Characterization of Shape Memory Alloy Composites for Designing Smart Structures

1999 ◽  
Author(s):  
Hugh A. Bruck ◽  
Charles L. Moore
Keyword(s):  
Mechanical Behavior ◽  
Shape Memory ◽  
Mechanical Response ◽  
Smart Structures ◽  
Constitutive Models ◽  
Computationally Efficient ◽  
Thermally Activated ◽  
Linear Rule ◽  
Computationally Intensive ◽  
Reasonable Prediction

Abstract Actuators with large displacement ranges are being designed for smart structures by utilizing the unconventional mechanical behavior of Shape Memory Alloys (SMAs). This behavior is characterized by deformation recovery through thermally activated phase transformations. However, because of this deformation mechanism, conventional constitutive models cannot be employed to predict the mechanical behavior of SMAs. Appropriate constitutive models have been proposed, but their application can be computationally intensive. In this investigation, SMA wire-reinforced fiberglass composites are fabricated to determine the relationship between the mechanical response of the composite and the composition of SMA wire reinforcement. A modified linear Rule-of-Mixtures (ROM) formulation is proposed for predicting the mechanical behavior of the SMA composites. This simple, uniaxial constitutive model provides a reasonable prediction of SMA composite mechanical behavior, and is computationally efficient enough to use with Finite Element Analyses for designing smart structures that contain heterogeneous compositions.

Effect of Water Content on the Mechanical Behavior of Thin Clay Films

2013 ◽  
Author(s):  
B. Carrier ◽  
M. Vandamme ◽  
R. J.-M. Pellenq ◽  
H. Van Damme
Keyword(s):  
Mechanical Behavior ◽  
Water Content ◽  
Effect Of Water ◽  
Thin Clay Films

Effect of water content on the resilient behavior of non standard unbound granular materials

2016 ◽  
Vol 7 ◽  
pp. 29-39 ◽  
Author(s):  
Octavio Coronado ◽  
Bernardo Caicedo ◽  
Said Taibi ◽  
Antonio Gomes Correia ◽  
Hanène Souli ◽  
...  
Keyword(s):  
Water Content ◽  
Granular Materials ◽  
Unbound Granular Materials ◽  
Effect Of Water ◽  
Resilient Behavior

Constitutive Models for the Passive Porcine Atria at the Healthy Stage and After Ventricular Tachypacing

2012 ◽  
Author(s):  
Chiara Bellini ◽  
Elena S. Di Martino
Keyword(s):  
Atrial Fibrillation ◽  
Mechanical Behavior ◽  
Mechanical Response ◽  
Constitutive Models ◽  
Local Arrangement ◽  
Biaxial Loads

Experimental measures of the mechanical response to planar biaxial loads and observations of the local arrangement of fibers were combined to generate average constitutive models for the atria at the healthy stage and after ventricular tachypacing. These models improve the understanding of the changes in the mechanical behavior of the atria induced by atrial fibrillation.

scholarly journals The Mechanical Response of Wet Volcanic Sand to Impact Loading, Effects of Water Content and Initial Compaction

2020 ◽  
Vol 6 (3) ◽  
pp. 358-372
Author(s):  
L. Varley ◽  
M. E. Rutherford ◽  
L. Zhang ◽  
A. Pellegrino
Keyword(s):  
Dynamic Response ◽  
Water Content ◽  
Mechanical Response ◽  
Split Hopkinson Pressure Bar ◽  
Initial Density ◽  
Mount Etna ◽  
Hopkinson Pressure Bar ◽  
Detection Analysis ◽  
Dry Conditions ◽  
Initial Compaction

Abstract The effects of water content and initial compaction on the dynamic response of volcanic sand from Mount Etna were investigated by a series of experiments on a long Split Hopkinson Pressure Bar apparatus capable of generating stress pulses of duration exceeding one millisecond. The dynamic stress–strain characteristics were determined until large final compressive strains were achieved. An experimental protocol for the preparation of samples characterised by different initial porosity and moisture content was defined in order to reproduce, in a laboratory environment, granular volcanic aggregates representative of naturally occurring soils in different initial density and water content states. It was found that, for limited amounts of water content, the dynamic response of the investigated volcanic wet sand is more compliant than in dry conditions. Conversely, highly saturated samples exhibit a steep increase in stiffness occurring at strains when the dynamic compressive behaviour becomes dominated by the response of the nearly incompressible water. The presence of water has negligible effect on the mechanical behaviour when the samples are loaded at quasi static strain rates. The grain size distribution and morphology of samples tested in different conditions were evaluated and compared by means of edge detection analysis techniques applied to high contrast images.

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