Crack band theory for fracture of concrete

Bažant, Zdeněk P.; Oh, Byung Hwan

doi:10.1007/bf02486267

Cited by 2,171 publications

(1,531 citation statements)

References 32 publications

Supporting

Mentioning

1,466

Contrasting

Unclassified

Order By: Relevance

“…In the 3D finite element analysis (FE) four nodes solid elements were used. To eliminate mesh sensitivity 3D FE analysis was carried out using crack band approach (Bažant and Oh [9]). …”

Section: Influence Of the Loading Rate On The Concrete Cone Failurementioning

confidence: 99%

Influence of loading rate on concrete cone failure

2006

View full text Add to dashboard Cite

In the present paper the rate sensitive model, which is based on the energy activation theory of bond rupture, and its implementation into the M2-O microplane model for concrete are discussed. It is first demonstrated that the new model realistically predicts the influence of the loading rate on the uniaxial compressive behaviour of concrete. The new rate sensitive microplane model is then applied in a 3D finite element study of the pull-out of the headed stud anchors from a concrete block. In the study the influence of the loading rate on the pull-out capacity and on the size effect are investigated. The anchors are loaded with relatively high loading rates. The results of the study show that with the increase of the loading rate the nominal pull-out resistance increases. Moreover, it has been found that the size effect on the concrete cone capacity is stronger when the loading rate is higher. The result of numerical study implies that it must exist a problem dependent critical loading rate for which the size effect is minimal. INTRODUCTIONIt is well known that the loading rate influence significantly structural response. The material response depends on the loading rate through influence two different effects: (1) through the rate dependency of the growing microcracks and (2) through the creep of the bulk material between the cracks. Depending on the material, it dominates the first or the second effect. For quasibrittle materials, such as a concrete, which exhibit cracking and damage phenomena the first effect dominates for very high loading rates (impact loading). This is especially thru for the case of recently observed phenomena (Bažant et al. [1]) for which a sudden increase of the loading rate in softening leads to reversal of softening into hardening. However, for lower loading rates the second effect is more important.In the literature can be found a number of theoretical and experimental studies that deal with the problem of the rate effect for different materials (for literature review see Bažant et al. [1]). In most of these studies various stress-displacement relations, similar to the spring-dashpot models of viscoelasticity, were used. However, as pointed out by Bažant et al.[1] these models performs well only for one order of magnitude of the loading rate. Here is for the rate dependency of the crack propagation adopted a model, which is applicable over many orders of magnitude of the loading rate. The model is based on the rate process theory (Krausz and Krausz [2]) of bond ruptures. It is coupled with the M2-O microplane model for concrete (Ožbolt et al. [3]), which has been shown to be capable to realistically simulate failure of concrete structures for complex threedimensional stress-strain states (Ožbolt [4]).Experience, a large number of experiments as well as numerical studies for anchors of different sizes confirm that fastenings are capable to transfer a tension force into a concrete member without using reinforcement (Eligehausen et al. [5]). Provided the steel strength of the a...

show abstract

“…In the 3D finite element analysis (FE) four nodes solid elements were used. To eliminate mesh sensitivity 3D FE analysis was carried out using crack band approach (Bažant and Oh [9]). …”

Section: Influence Of the Loading Rate On The Concrete Cone Failurementioning

confidence: 99%

Influence of loading rate on concrete cone failure

2006

View full text Add to dashboard Cite

show abstract

“…Up to this point, particle size l min = 15 mm was used. Since this model uses crack band concept [3], the discretization does not influences the model response for cases where the crack is localized. However, the cracking in the loading area is highly distributed and strong dependence on discretization density is expected.…”

Section: Peak Loadsmentioning

confidence: 99%

“…Material remains continuous, but its stiffness is being reduced as cracking occurs. Such approach brings need for regularization [3,2]. Several other approaches incorporating discontinuities into FEM models has been presented in literature [10].…”

Section: Introductionmentioning

confidence: 99%

Simulations of Concrete Fracture at Various Strain Rates: Parametric Study

Květoň¹,

Eliáš²

2017

Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

View full text Add to dashboard Cite

Abstract. The contribution presents numerical simulations of a recently published experimental series on concrete specimens. The numerical model mimics the meso-structure of the concrete by representing material via system of interconnected rigid polyhedral particles. These particles correspond to mineral aggregates and surrounding matrix. The geometry of particles is based on Voronoi tessellation. The particles are rigid, but they may move and rotate. The displacement jump at their contacts gives rise interaction forces defined by the constitutive relation in a vectorial form. The constitutive equations are independent of the strain rate. Simulations are dynamical, the time dependent response is calculated using Newmark implicit scheme. Full inertia tensor of every particle is taken into account when assembling the mass matrix.To demonstrate the ability of the model to capture the strain rate dependence of the experimental results, series of specimens loaded under various displacement rates are simulated. For quasi-static loading, the initial microcracks usually localize into one highly damaged zone where main crack appears. With increasing strain rate, the amount of energy accumulated in the specimen body is not consumed by one crack only and crack branching occurs. The peak loading force increases with increasing rate as well.Both the strain rate dependence of the loading force and crack branching phenomena are captured by the presented numerical model. The obtained results are compared with the experimental response of the simulated specimens. Parametric study of the model is performed showing different effect of various parameters under different strain rates.

show abstract

“…On the other hand, several analytical models have been proposed in order to assess the performance of shear critical members. Authors such as Litton [5], Bazant and Oh [6], Cervenka [7], Vecchio and Collins [8], De Borst [9], Hsu [10] and Maekawa et al [11], have developed methods to determine the shear behaviour of RC, using diverse types of assumptions in the process. As defined in Ceresa et al [12] [13], in the framework of smeared crack theory for RC the following main models can be identified:…”

Section: Background and Motivationmentioning

confidence: 99%