Mesoscale modeling of concrete: Geometry and numerics

Hafner, S. S.; Eckardt, Stefan; Luther, Torsten; Könke, Carsten

doi:10.1016/j.compstruc.2005.10.003

Cited by 229 publications

(82 citation statements)

References 20 publications

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“…Garboci [25] used voxel representations of real concretes to describe the size and shape of particles in concrete by spherical harmonics, which allows the simulation of random shapes. Häfner et al [26] combine a modified ellipsoid with a sine function to take into account the roundness, the sphericity and the surface roughness of the particles. In order to obtain realistic models, certain statistical characteristics of the real model, e.g.…”

Section: Generation Of the Internal Materials Structure On The Mesoscalementioning

confidence: 99%

Multiscale Modeling of Concrete

Unger

Eckardt

2011

Arch Computat Methods Eng

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235

103

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In this paper, a mesoscale model of concrete is presented, which considers particles, matrix material and the interfacial transition zone (ITZ) as separate constituents. Particles are represented as ellipsoides, generated according to a prescribed grading curve and placed randomly into the specimen. Algorithms are proposed to generate realistic particle configurations efficiently. The nonlinear behavior is simulated with a cohesive interface model for the ITZ. For the matrix material, different damage/plasticity models are investigated. The simulation of localization requires to regularize the solution, which is performed by using integral type nonlocal models with strain or displacement averaging. Due to the complexity of a mesoscale model for a realistic structure, a multiscale method to couple the homogeneous macroscale with the heterogeneous mesoscale model in a concurrent embedded approach is proposed. This allows an adaptive transition from a full macroscale model to a multiscale model, where only the relevant parts are resolved on a finer scale. Special emphasis is placed on the investigation of different coupling schemes between the different scales, such as the mortar method and the arlequin method, and a discussion of their advantages and disadvantages within the current context. The applicability of the proposed methodology is illustrated for a variety of examples in tension and compression.

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Section: Generation Of the Internal Materials Structure On The Mesoscalementioning

confidence: 99%

Multiscale Modeling of Concrete

Unger

Eckardt

2011

Arch Computat Methods Eng

Self Cite

235

103

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“…The geometries of the concrete constituents are simplified using basic shapes such as ellipsoids (aggregate grains) and spheres (air voids), which are randomly distributed in space as suggested by Schubert and Schechinger (2002). More complex approximations for particle shapes such as presented in Häfner et al (2006) are not deemed necessary. This refinement provides little additional information for the simulation of wave propagation for a governing wavelength of Λ ∼ = 4.0 cm (c p,eff ∼ = 4,000 m/s and f c = 100 kHz).…”

Section: Numerical Concrete Modelmentioning

confidence: 99%

Crack localization in a double-punched concrete cuboid with time reverse modeling of acoustic emissions

2011

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Time reverse modeling (TRM) is successfully applied to localize acoustic emissions (AE) obtained from a physical experiment (double punch test) on a 118 × 120 × 160 mm concrete cuboid. Previously, feasibility studies using numerical (Ricker wavelet) and experimental (pencil-lead break) excitations are performed to demonstrate the applicability of TRM to real AE waveforms. Numerical simulations are performed assuming an uncracked and heterogeneous concrete model. The localization results from the numerical and experimental feasibility studies are compared and verified. The AE recorded during the double punch test are localized in a three-dimensional domain using TRM. The localization results are superposed with the three-dimensional threshold-segmented crack patterns obtained from X-ray computed tomography scans of the failed concrete cuboid. The presented TRM approach represents a reliable localization tool for signal-based AE analysis.

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“…Classical experimental results have shown that the "apparent" dynamic compressive strength increases with 04038-p. 4 DYMAT 2015 the increase of the strain rate. A Dynamic Increase Factor (DIF), which is defined as the ratio of the apparent dynamic strength to the static strength of the sample specimens, is commonly used to account for the strength enhancement due to high strain rates.…”

Section: Dynamic Compressionmentioning

confidence: 99%

“…To circumvent this difficulty, simple shapes of aggregate particles like spheres or mixed spheres and ellipsoids are mostly used in previous research. Further proposal of a modified version of the ellipsoid function [4] made it possible to better approximate real aggregates. Recently a more accurate approximation of particle shapes represented by polyhedrons has been adopted by some researchers.…”

Section: Introductionmentioning

confidence: 99%

A 3-D perspective of dynamic behaviour of heterogeneous solids

Zhou

2015

EPJ Web of Conferences

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Abstract. The dynamic behaviour of concrete-like materials under high strain rates has been a subject of continuous scrutiny over the years. A prevailing explanation attributes much of the dynamic increase of strength, especially under compression, to the macroscopic inertia confinement. Studies conducted by the authors' group using meso-scale computational models suggest that the heterogeneity of the material composition, in particular the involvement of the aggregates, also plays a sensible part in the process of damage evolution and the increase of the bulk strength under high strain rates, and a detailed investigation into this effect would benefit if a realistic representation of the heterogeneity in 3D can be achieved. This paper presents some recent progress in the development of a 3-D meso-scale computational model incorporating randomly-shaped 3-D aggregate particles, including the general validation of the model, and application in the simulation of the dynamic response of concrete under high strain rate compression.

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Mesoscale modeling of concrete: Geometry and numerics

Cited by 229 publications

References 20 publications

Multiscale Modeling of Concrete

Multiscale Modeling of Concrete

Crack localization in a double-punched concrete cuboid with time reverse modeling of acoustic emissions

A 3-D perspective of dynamic behaviour of heterogeneous solids

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