Search results

1 – 10 of over 3000
To view the access options for this content please click here
Article
Publication date: 1 February 1988

Gilles Pijaudier‐Cabot, Zdeněk P. Bažant and Mazen Tabbara

This paper presents a comparison of various models for strain‐softening due to damage such as cracking or void growth, as proposed recently in the literature. Continuum

Abstract

This paper presents a comparison of various models for strain‐softening due to damage such as cracking or void growth, as proposed recently in the literature. Continuum‐based models expressed in terms of softening stress—strain relations, and fracture‐type models expressed in terms of softening stress—displacement relations are distinguished. From one‐dimensional wave propagation calculations, it is shown that strain‐localization into regions of finite size cannot be achieved. The previously well‐documented spurious convergence is obtained with continuum models, while stress—displacement relations cannot model well smeared‐crack situations. Continuum models may, however, be used in general if a localization limiter is implemented. Gradient‐type localization limiters appear to be rather complicated; they require solving higher‐order differential equations of equilibrium with additional bourdary conditions. Non‐local localization limiters, especially the non‐local continuum with local strain, in which only the energy dissipating variables are non‐local, is found to be very effective, and also seems to be physically realistic. This formulation can correctly model the transition between homogeneous damage states and situations in which damage localizes into small regions that can be viewed as cracks. The size effect observed in the experimental and numerical response of specimens in tension or compression is shown to be a consequence of this progressive transition from continuum‐type to fracture‐type formulations.

Details

Engineering Computations, vol. 5 no. 2
Type: Research Article
ISSN: 0264-4401

To view the access options for this content please click here
Article
Publication date: 1 March 1992

C. SAOURIDIS and J. MAZARS

Simple but also accurate models are needed to predict the failure response of concrete structures. Simplicity involves modelling assumptions while accuracy involves…

Abstract

Simple but also accurate models are needed to predict the failure response of concrete structures. Simplicity involves modelling assumptions while accuracy involves objectivity of both the experimentally identified model parameters and the numerica results. For concrete‐like heterogeneous and brittle materials, the modelling assumptions idealizing the material as a homogeneous continuum with classical linear or non‐linear behaviour, leads to some problems at the identification stage, namely the size effect phenomena. A continuum damage model, representing the non‐linear behaviour due to microcracking, is proposed here for predictive computations of structural responses. A Weibull based theory is used to determine, in a statistical sense, the value of the initial damage threshold. The essential influence of material heterogeneity on the damage evolution, is accounted for with a bi‐scale approach which is based on the idea of the non‐local continuum with local strain. It has already established that the non‐local approaches yield realistic failure predictions and the numerical results are convergent for subsequent mesh refinements. The applications presented here show the ability of the approach to predict the failure response of concrete structures without being obscured by size effect problems.

Details

Engineering Computations, vol. 9 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 24 February 2012

Juha Kuutti and Kari Kolari

The purpose of this paper is to present a new simplified local remeshing procedure for the study of discrete crack propagation in finite element (FE) mesh. The proposed…

Abstract

Purpose

The purpose of this paper is to present a new simplified local remeshing procedure for the study of discrete crack propagation in finite element (FE) mesh. The proposed technique accounts for the generation and propagation of crack‐like failure within an FE‐model. Beside crack propagation, the technique enables the analysis of fragmentation of initially intact continuum. The capability of modelling fragmentation is essential in various structure‐structure interaction analyses such as projectile impact analysis and ice‐structure interaction analysis.

Design/methodology/approach

The procedure combines continuum damage mechanics (CDM), fictitious crack approach and a new local remeshing procedure. In the approach a fictitious crack is replaced by a discrete crack by applying delete‐and‐fill local remeshing. The proposed method is independent of mesh topology unlike the traditional discrete crack approach. The procedure is implemented for 3‐D solid elements in commercial finite element software Abaqus/Explicit using Python scripting. The procedure is completely automated, such that crack initiation and propagation analyses do not require user intervention. A relatively simple constitutive model was implemented strictly for demonstrative purposes.

Findings

Well known examples were simulated to verify the applicability of the method. The simulations revealed the capabilities of the method and reasonable correspondence with reference results was obtained. Material fragmentation was successfully simulated in ice‐structure interaction analysis.

Originality/value

The procedure for modelling discrete crack propagation and fragmentation of initially intact quasi‐brittle materials based on local remeshing has not been presented previously. The procedure is well suited for simulation of fragmentation and is implemented in a commercial FE‐software.

To view the access options for this content please click here
Article
Publication date: 5 March 2010

Aidy Ali, Maryam Hosseini and Barkawi Sahari

The purpose of this paper is to investigate the fatigue behavior of rubber using dumb‐bell test specimens under uniaxial loading.

Abstract

Purpose

The purpose of this paper is to investigate the fatigue behavior of rubber using dumb‐bell test specimens under uniaxial loading.

Design/methodology/approach

The material used is a vulcanized natural rubber with a formulation typical for engine mounts and an international rubber hardness degree of 60. Fatigue tests are conducted under the displacement controlled condition with a sine waveform of 0.1 Hz and the load ratio of zero.

Findings

In modeling fatigue damage behavior, a continuum damage model is presented based on the function of the strain range under cyclic loading. The Ogden strain energy potential is used to define the constitutive relation of the natural rubber. A good agreement is obtained between fatigue experimental data and theoretical predictions.

Originality/value

Fatigue analysis and lifetime evaluation are very important in design to ensure the safety and reliability of rubber components. The design of rubber against fatigue failure is an important topic that must be considered for safety during operation.

Details

International Journal of Structural Integrity, vol. 1 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

To view the access options for this content please click here
Article
Publication date: 1 July 2005

Norberto Dominguez, Delphine Brancherie, Luc Davenne and Adnan Ibrahimbegović

To provide a reinforced concrete model including bonding coupled to a classical continuum damage model of concrete, capable of predicting numerically the crack pattern…

Abstract

Purpose

To provide a reinforced concrete model including bonding coupled to a classical continuum damage model of concrete, capable of predicting numerically the crack pattern distribution in a RC structure, subjected to traction forces.

Design/methodology/approach

A new coupling between bonding model and an alternative model for concrete cracking is proposed and analyzed. For concrete, proposes a damage‐like material model capable of combining two types of dissipative mechanisms: diffuse volume dissipation and localized surface dissipation.

Findings

One of the most important contributions is the capacity of predicting maximal and minimal spacing of macro‐cracks, even if the exact location of cracks remains undetermined. Another contribution is to reiterate on the insufficiency of the local damage model of concrete to handle this class of problems; much in the same manner as for localization problem which accompany strain‐softening behavior.

Practical implications

Bonding becomes very important to evaluate both the integrity and durability of a RC structure, or in particular to a reliable prediction of crack spacing and opening, and it should be integrated in future analysis of RC.

Originality/value

Shows that introduction of the influence of concrete heterogeneities in numerical analysis can directly affect the configuration of the crack pattern distribution. Use of a strong discontinuity approach provides additional cracking information like opening of macro‐cracks.

Details

Engineering Computations, vol. 22 no. 5/6
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 4 June 2021

Jike Han, Bo Yin, Michael Kaliske and Kenjiro Tarada

This study aims to develop a new analysis approach devised by incorporating a gradient-enhanced microplane damage model (GeMpDM) into isogeometric analysis (IGA), which…

Abstract

Purpose

This study aims to develop a new analysis approach devised by incorporating a gradient-enhanced microplane damage model (GeMpDM) into isogeometric analysis (IGA), which shows computational stability and capability in accurately predicting crack propagations in structures with complex geometries.

Design/methodology/approach

For the non-local microplane damage modeling, the maximum modified von-Mises equivalent strain among all microplanes is regularized as a representative quantity. This characterization implies that only one additional governing equation is considered, which improves computational efficiency dramatically. By combined use of GeMpDM and IGA, quasi-static and dynamic numerical analyses are conducted to demonstrate the capability in predicting crack paths of complex geometries in comparison to FEM and experimental results.

Findings

The implicit scheme with the adopted damage model shows favorable numerical stability and the numerical results exhibit appropriate convergence characteristics concerning the mesh size. The damage evolution is successfully controlled by a tension-compression damage factor. Thanks to the advanced geometric design capability of IGA, the details of crack patterns can be predicted reliably, which are somewhat difficult to be acquired by FEM. Additionally, the damage distribution obtained in the dynamic analysis is in close agreement with experimental results.

Originality/value

The paper originally incorporates GeMpDM into IGA. Especially, only one non-local variable is considered besides the displacement field, which improves the computational efficiency and favorable convergence characteristics within the IGA framework. Also, enjoying the geometric design ability of IGA, the proposed analysis method is capable of accurately predicting crack paths reflecting the complex geometries of target structures.

Details

Engineering Computations, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 1 May 1993

Z.P. WANG, D.R. HAYHURST, B.A. BILBY and I.C. HOWARD

Two non‐linear finite element programs have been restructured by using vectorization techniques in order to run efficiently on the Cray X‐MP/416. One of them has also been…

Abstract

Two non‐linear finite element programs have been restructured by using vectorization techniques in order to run efficiently on the Cray X‐MP/416. One of them has also been multi‐tasked to take advantage of the four processors of the machine. The techniques used in restructuring the software are discussed, and it is shown that each program must be treated individually. The resulting speed enhancements are shown to be program dependent, with a speed‐up of approximately 20 being achieved with one of the programs.

Details

Engineering Computations, vol. 10 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 2 January 2009

D. Brancherie and A. Ibrahimbegovic

The purpose of this paper is to present a finite element model capable of describing both the diffuse damage mechanism which develops first during the loading of massive…

Abstract

Purpose

The purpose of this paper is to present a finite element model capable of describing both the diffuse damage mechanism which develops first during the loading of massive brittle structures and the failure process, essentially due to the propagation of a macro‐crack responsible for the softening behaviour of the structure. The theoretical developments for such a model are presented, considering an isotropic damage model for the continuum and a Coulomb‐type criterion for the localized part.

Design/methodology/approach

This is achieved by activating subsequently diffuse and localized damage mechanisms. Localized phenomena are taken into account by means of the introduction of a displacement discontinuity at the element level.

Findings

It was found that, with such an approach, the final crack direction is predicted quite well, in fact much better than the prediction made by the fracture mechanics type of models considering combination of only elastic response and softening.

Originality/value

The presented model has the potential to describe complex damage phenomena in a cyclic and/or non‐proportional loading program, such as crack closing and re‐opening, cohesive resistance deterioration due to tangential sliding, by using only a few parameters compared to the traditional models for cyclic loading.

Details

Engineering Computations, vol. 26 no. 1/2
Type: Research Article
ISSN: 0264-4401

Keywords

To view the access options for this content please click here
Article
Publication date: 4 November 2014

ShiYang Zhao and Pu Xue

– The purpose of the paper is to improve the calculability of a continuum damage failure model of composite laminates based on Tsai-Wu criteria.

Abstract

Purpose

The purpose of the paper is to improve the calculability of a continuum damage failure model of composite laminates based on Tsai-Wu criteria.

Design/methodology/approach

A technique based on viscous regularization, a characteristic element length and fracture energies of fiber and matrix are used in the model.

Findings

The calculability of the material model is improved. The modified model can predict the behavior of composite structure better.

Originality/value

The convergence problem and the mesh softening problem are main concern in the calculability of numerical model. In order to improve the convergence, a technique based on viscous regularization of damage variable is used. Meanwhile, characteristic element length and fracture energies of fiber and matrix are added into the damage constitutive equation to reduce the mesh sensitivity of numerical results. Finally, a laminated structure with damages is implemented using a User Material Subroutine in ABAQUS/Standard. Mesh sensitivity and value of viscosity are discussed.

Details

Multidiscipline Modeling in Materials and Structures, vol. 10 no. 4
Type: Research Article
ISSN: 1573-6105

Keywords

To view the access options for this content please click here
Article
Publication date: 19 September 2018

Niraj Kumar Jha and Udo Nackenhorst

The purpose of this paper is to develop a progressive damage framework to predict the fatigue life of cord-reinforced rubber composite under cyclic loadings. Special…

Abstract

Purpose

The purpose of this paper is to develop a progressive damage framework to predict the fatigue life of cord-reinforced rubber composite under cyclic loadings. Special attention has been paid to failure mechanisms, like cord–rubber interfacial debonding, and rubber matrix damage.

Design/methodology/approach

The constitutive modeling is based on the continuum damage mechanics (CDMs) and the thermodynamics of irreversible process. The damage in rubber is described by an istropic law, whereas elasto-plastic continuum model has been proposed for cord–rubber interphase layer. The numerical framework is implemented into commercial finite element code Abaqus/Standard via user subroutine (UMAT).

Findings

One of the most important findings obtained from reviewing various techniques is that meso-level fatigue damage modeling based on developed framework can simulate competitive damage scenarios, e.g. debonding, delamination or matrix failure.

Originality/value

A systematic framework for predicting failure in cord-reinforced rubber composite is formulated within the context of CDMs that can also be applied for industrial components, such as tires and airsprings.

Details

Engineering Computations, vol. 35 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

1 – 10 of over 3000