Topic
Embedment
About: Embedment is a research topic. Over the lifetime, 2441 publications have been published within this topic receiving 31444 citations.
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01 Jan 2012
TL;DR: In this article, a micromechanical constitutive model for concrete is proposed, in which microcracks initiation, in the interfacial transition zone between aggregate particles and a matrix, is governed by an exterior-point Eshelby solution.
Abstract: A micromechanical constitutive model for concrete is proposed in which
microcrack initiation, in the interfacial transition zone between aggregate particles and
cement matrix, is governed by an exterior-point Eshelby solution. The model assumes a
two-phase elastic composite, derived from an Eshelby solution and the Mori-Tanaka
homogenization method, to which circular microcracks are added. A multi-component
rough crack contact model is employed to simulate normal and shear behaviour of rough
microcrack surfaces. It is shown, based on numerical predictions of uniaxial, biaxial and
triaxial behaviour that the model captures key characteristics of concrete behaviour. An
important aspect of the approach taken in this work is the adherence to a mechanistic
modelling philosophy. In this regard the model is distinctly more rigorously mechanistic
than its more phenomenological predecessors.
Following this philosophy, a new more comprehensive crack-plane model is
described which could be applied to crack-planes in the above model. In this model the
crack surface is idealised as a series of conical teeth and corresponding recesses of
variable height and slope. Based on this geometrical characterization, an effective
contact function is derived to relate the contact stresses on the sides of the teeth to the
net crack-plane stresses. Plastic embedment and frictional sliding are simulated using a
local plasticity model in which the plastic surfaces are expressed in terms of the contact
surface function. Numerical simulations of several direct shear tests indicate a good
performance of the model. The incorporation of this crack-plane model in the overall
constitutive model is the next step in the development of the latter.
Computational aspects such as contact related numerical instability and accuracy
of spherical integration rules employed in the constitutive model are also discussed. A
smoothed contact state function is proposed to remove spurious contact chatter
behaviour at a constitutive level.
Finally, an initial assessment of the performance of the micromechanical model
when implemented in a finite element program is presented. This evaluation clearly
demonstrates the capability of the proposed model to simulate the behaviour of plain
and reinforced concrete structural elements as well as demonstrating the potential of the
micromechanical approach to achieve a robust and comprehensive model for concrete.
15 citations
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TL;DR: In this article, the average rate of microparticle embedment is linearly dependent on the static force and compression of the CM, and is described by a quadratic relationship between the diameter of the microparticles and the amplitude of the USV.
Abstract: 1.
Use of ultrasonic activity on microparticles in the TR process of CM makes it possible to intensify the reinforcement process significantly and simultaneously to reduce by a factor of three-four the effect of the material's resistance forces to the embedment of microparticles without reducing the quality of the CM obtained.
2.
It is established that the average rate of microparticle embedment is linearly dependent on the static force and compression of the CM, and is described by a quadratic relationship between the diameter of the microparticle and the amplitude of the USV.
3.
Optimal ranges of variation in the TR parameters are determined. It is shown that the 10–15-μm USV-amplitude range is optimal.
15 citations
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TL;DR: In this article, a three-dimensional microscale framework utilizing the discrete element method (DEM) is presented to analyze the seismic response of soil-foundation-structure systems, where the spread footing is modeled as a rigid block composed of clumped particles and its motion is described by the resultant forces and moments acting upon it.
15 citations
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TL;DR: In this article, an experimental study of the lateral behavior of vertical pile groups embedded in reinforced and nonreinforced sandy earth slopes was carried out, which included studies of group configurations, pile spacing, embedment length of pile, relative densities of sand, and location of pile groups relative to the slope crest.
Abstract: An experimental study of the lateral behavior of vertical pile groups embedded in reinforced and nonreinforced sandy earth slopes was carried out. The model tests include studies of group configurations, pile spacing, embedment length of pile, relative densities of sand, and location of pile groups relative to the slope crest. Several configurations of geogrid reinforcement with different lengths, widths, and number of layers were used to reinforce a sandy slope of 1 (V) : 1.5 (H) . Pile groups of 2×2 and 3×3 along with center-to-center pile spacing of 2D , 3D , and 4.5D and piles with embedment length to diameter ratios of L∕D=12 and 22 were considered. Based on test results, geogrid parameters that give the maximum lateral capacity improvement are presented and discussed.
15 citations
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TL;DR: In this article, the European yield model is used to determine the connection strength of timber structures and an alternative is proposed to use more reliable timber connections in applying the European Yield Model.
Abstract: Different test setups for determining perpendicular to grain embedment strength of timber have been reported in literature. In addition, different definitions of strength have been used associated with the deformation level underneath the fastener. It is shown that all reported experimental results can be related, which enables comparison on a common basis. Furthermore, several models for embedment strength perpendicular to the grain which primarily depend on timber density (specific gravity) and fastener diameter are evaluated. It is shown that the model currently prescribed by the European structural timber design code [Comite Europeen de Normalisation (CEN) EN 1995-1-1: 2004: Eurocode 5—design of timber structures. Part 1.1: general rules and rules for buildings. CEN, Brussels, 2004] is unable to accurately predict the strength and an alternative is proposed. This may result in more reliable timber connections in applying the European Yield Model to determine the connection strength.
14 citations