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Callovo-Oxfordian (COx) claystone has been considered as a potential host rock for geological radioactive waste disposal in France (Cigéo project). During the exploitation phase (100 years), the stability of drifts (e.g. galleries/alveoli) within the disposal is assured by the liner, which includes two layers: concrete arch segment and compressible material. The latter exhibits a significant deformation capacity (about 50%) under low stress (

The load reduction mechanism of compressible material filled ditch covered with a geosynthetic layer is investigated. A mathematical model of the pressure on the roof of the culvert is established....

In this work we demonstrate that the incompressibility constraint customarily adopted in literature to model soft dielectric composites may lead to incorrect predictions. In fact, although in these composites each phase may individually be assumed to be incompressible, for high-phase contrast in terms of elastic moduli the volumetric deformation of the softest phase can provide a non-negligible contribution to the effective behaviour. To reach our goal, we determine the effective electric response of a two-phase Dielectric Laminated Composite (DLC) actuator, whose softest phase is described by a constitutive law admitting volumetric deformation. Our results, discussed in the light of the limit case in which the softest phase consists of void, are expected to aid the design of high-performance hierarchical DLCs.

The paper considers a laboratory study of fracture development in a porous medium as applied to hydraulic fracturing. The experiments were carried out on a Hele-Shaw cell. In the first case, the cell was filled with a compressible permeable medium into which glycerin was injected, in the second case with a compressible impermeable medium into which water was injected under pressure. As a result, the conditions for the formation of cracks were obtained, as well as the conditions for maintaining their geometry. The dependences of the fracture growth rate on the pressure of the injected fluid were obtained. Comparison of the obtained dependences showed that the rate of crack propagation does not depend on the pressure of the injected fluid, but the pressure affects its length.

Lateral swelling pressures of expansive soils impose significant threats to the stability and safety of retaining structures. Placing a layer of compressible material, such as cohesive non-swelling soil (CNS), expanded polystyrene (EPS) geofoam or cohesionless soil (such as sand), between the retaining structure and the expansive soil can effectively reduce the lateral swelling pressure acting on the retaining structure. The work presented in this paper compares the efficiency of CNS, EPS and sand inclusions in reducing the lateral swelling pressure of a natural expansive clay. A special consolidometer was used to measure the lateral swelling pressure of expansive soil samples with and without inclusions under constant-volume condition, upon saturation. An analytical approach was used to interpret the efficiency of CNS, EPS and sand inclusions in reducing the lateral swelling pressure. It is found that (i) the efficiency of EPS inclusions is much higher than that of CNS and sand inclusions and (ii) sand is more effective than CNS in reducing the lateral swelling pressure at the same degree of compaction. It is suggested that EPS is preferred, the efficiency of sand is limited, and highly compacted CNS is unfavorable in reducing lateral swelling pressures.

Airplanes need tire-pavement friction during taxiing, take-off and landing. The presence of snow reduces the friction and therefore there is need to understand how much friction can be expected on the different types of snow. This study analyses the braking performance of Boeing 737 airplanes on snow or slush contaminated runways. Airplane braking performance on runways contaminated with dry snow, wet snow and slush as analysed. The main finding is that airplanes experienced wet snow covered runways more often as very slippery, compared to slush covered runways. The fraction of the landings experiencing the conditions as “poor” or “less than poor” was significantly higher on wet snow (21%), compared to landings on slush (11%). This can be caused due to higher precipitation intensity during wet snow precipitation, or possibly because wet snow, in contrast to slush, is a compressible material that gets compacted and fills the underlying pavement texture. © 2017. This is the authors’ accepted and refereed manuscript to the article. Locked until 20.2.2019 due to copyright restrictions. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

The results of long-term geodetic observations in the formation of phosphogypsum dump of the Balakovo branch JSC "Apatit" in the Saratov region, which allowed studying the regularities of development of deformation processes due to the simultaneous occurrence of landslide displacements and settlements of the dump’s surface, are presented. The causes, mechanism, dynamics and conditions of formation of landslides on the phosphogypsum dump, including the impact of the technogenic aquifer on the bearing capacity of the structure base changing, are discussed. Laboratory studies of phosphogypsum describe its as a highly compressible material with marked rheological properties. This fact determines the development of the large settlements of phosphogypsum dumps continuous in time. Presented knowledge in this work can be useful in assessing the sustainability of phosphogypsum dumps and the determination of their maximum capacity.

In the article, “Investigation of histology region in dielectric measurements of heterogeneous tissues,” by Porter and O’Halloran, the authors utilize a flexible phantom in a layered material dielectric property analysis to quantify the effective sensing volume of a coaxial dielectric probe. Ostensibly, this test has been used by others to characterize the region for which percent variation in the material composition in front of the probe corresponds to percent variation in the computed effective dielectric properties. By employing a compressible material, the authors fail to isolate features that are attributable solely to the probe, itself, and inadvertently incorporate confounding characteristics associated with the compressible nature of the material. The net effect is to exaggerate the probe’s sensing volume, which undermines the conclusions drawn from the subsequent tissue dielectric property studies.

In this article we obtain exact solutions of finite inhomogeneous deformations of three-dimensional micropolar elastic bodies. We consider a model of the physically linear isotropic compressible material with six material parameters. The obtained solutions describe following types of finite deformations: cylindrical bending of a rectangular plate, straightening of a cylindrical sector, double cylindrical bending, pure bending of a circular cylinder sector, inflation and reversing of a hollow sphere. The results can be used to verify two-dimensional models of micropolar elastic shells.

Using first principles calculation, the structural and mechanical properties of BP$_3$N$_6$ which adopts an orthorhombic structure with space group Pna2$_1$ (no. 33), were determined at three different pressure values (0, 20 and 42.4~GPa). The nine independent elastic constants meet all necessary and sufficient conditions for mechanical stability criteria for an orthorhombic crystal. BP$_3$N$_6$ show strong resistance to volume change hence a potential low compressible material. The Vicker's hardness of BP$_3$N$_6$ was found to range between 49-51~GPa for different external pressures imposed on the crystal. These high values of Vicker's hardness implies that BP$_3$N$_6$ is a potential superhard material., Comment: 6 pages, 1 figure

The plane problem on large deformations of the flexure of a composite rectangular beam consisting of two layers, one of which is preliminarily deformed, has been solved. An exact analytical solution of this problem is derived for the case when the beam is made of a compressible nonlinearly elastic material, the mechanical properties of which are described by the John potential. When stating and solving the problem, the theory of imposing large deformations is used. Based on the calculations, the influence of the prestressed layer on a strong flexure of a composite beam is determined.

The intermediate results of the study of planar problems about perturbation by movable surface load of multilayer base with initial (residual) stresses are presented. Within the bounds of linearizired theory of elasticity for bodies with initial stresses there are considered the statement and method of solving a planar problem of the perturbation of the surface load moving with a constant speed of two-layered pre-stressed stripe with the rigid basis. The model of the layered medium “a plate and pre-stressed layer” is considered. Equations of plate motion are written taking into account the shift and rotary inertia. Layer material is assumed compressible, isotropic in the natural state. The form of elastic potential has a general form and must be specified only while implementation of numeral calculations. With the help of the Fourier integral transform method a fundamental solution to the problem is obtained in general form under various conditions of contact and speeds of load.

In the mathematical model of the flow of compressible material the effect of friction and the slip velocity of the material at the side boundary surfaces are considered. The dependence of the slip velocity on the average velocity at the entrance of the channel is built.

Using the theory of plasticity for porous bodies and finite-element computer simulation, the stress–strain state around spherical and conical indenters has been studied for different mechanical properties of indented material. Porosity distribution near the indenter depending on the properties of the porous body and on its friction against the indenter has been analyzed. Load–displacement curves with respect to tendency to dilatancy and contact friction are shown. The development and shape of bulks around the indenter have been studied.

Elastoplastic solutions for thin plates and disks are sensitive to loading and plasticity conditions [1–5]. The plasticity condition for a number of metal materials depends on the mean stress [6–8]. In this case, when using the associated flow rule, plastic deformations do not satisfy the incompressibility condition, which is commonly accepted in statements of boundary-value problems for thin elastoplastic plates and disks [9–13]. It is of interest to determine the effect of plastic compressibility on the behavior of solutions for such structures. In this paper, a hollow disk in a rigid container subjected to a uniform temperature field is considered. The plasticity condition proposed in [14] is accepted. A general study of the set of equations including this plasticity condition and the associated flow rule was performed in [15]. The solution under the Mises plasticity condition was obtained in [1].

Carbon-based materials that bounce back when you press them are in demand for flexible electronics and energy storage devices alike. Most of the available options have limitations, though: They come from nonrenewable sources, have inferior electrical properties, or are difficult to manufacture on scale. Now, researchers have revealed a compressible material with promising electrical properties from a sustainable, if somewhat surprising, source: wood. University of Maryland, College Park, engineer Liangbing Hu presented the work last week at the ACS national meeting in New Orleans. To make the spongy material, Hu, postdoctoral researcher Chaoji Chen, and colleagues were inspired by honeycombs, which have a wavy lattice that stands up to compression. They hypothesized they might be able to chemically change wood’s architecture to achieve a similar effect. Indeed, by stripping away lignin and hemicellulose from a block of balsa wood, they transformed the wood’s rigid, boxlike cell walls into a lattice

The filtration of suspensions in the colloidal regime is part of many processes. It is necessary due to the widespread use of nano-size particles in many applications. In nano-scale particle systems, the huge specific surface of the particles is dominating the processes. The question is whether the well-known filter theory is applicable for such type of products. The experiments in this study were conducted by gas-driven filtration. The analysis of the filter cake was done globally according to the Darcy equation and locally by the use of magnetic resonance imaging (MRI) techniques. Due to the very high resistances during filtration for colloidal suspensions, comparatively thin filter cakes with an approximate height of 0.5–3 mm were investigated. The overall porosities determined by the different techniques are in good agreement. The MRI technique allows an in situ measurement of the porosity gradient within a filter cake formed by compressible material.

This paper deals with the prediction of the macroscopic behavior of a multiphase elastic–viscoplastic material. The proposed homogenization schemes are based on an interaction law postulated by Molinari et al. [Molinari, A., Ahzi, S., Kouddane, R. 1997. On the self-consistent modelling of elastic–plastic behavior of polycrystals. Mech. Mater., 26, 43–62]. Self-consistent schemes are developed to describe the behavior of disordered aggregates. The Mori-Tanaka approach is used to capture the behavior of composite materials, where one phase can be clearly identified as the matrix. The proposed schemes are developed within a general framework where compressible elasticity and anisotropy of the materials are taken into account. Inclusions can have various shapes and orientations. Illustrations of the homogenization procedure are given for a two-phase composite materials. Comparisons between results of the literature and predictions based on the interaction law are performed and have demonstrated the efficiency of the proposed homogenization schemes.