Study of the progressive failure of concrete by phase field modeling and experiments

In this research, experiments and numerical simulations are employed to research the failure process of concrete. Fracture experiments on three-point bending (TPB) concrete beams with a prefabricated edge notch at the middle of the beam bottom are performed using a modified rigid testing instrument. The characteristics of the crack and section are analyzed, including the crack tensile opening displacement, crack length and width, and crack faces characteristics. Also, the full curves of the force-crack tensile opening displacement (CMOD) and force-deflection of the TPB beams with the prefabricated edge notch after breakage are obtained. The phase field (PF) damage model is applied to the mixed-mode and mode-I failure processes of concrete structures through the ABAQUS subroutine user defined element (UEL). The crack path and the full curves of force-CMOD and force-deflection obtained by numerical calculations are consistent with the experimental results and the calculated results of other researchers. The influences of the mesh sizes, initial lengths, and notched depths on the TPB beam of concrete are also analyzed.

Download Full-text

Numerical Simulation of Fracture Process of Three-Point Bending Beam of Concrete Based on Modified Mazars Model

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.295-297.2097 ◽

2011 ◽

Vol 295-297 ◽

pp. 2097-2101

Author(s):

Ai Min Deng ◽

Lian Meng Gou ◽

Dao Yuan Xu

Keyword(s):

Numerical Simulation ◽

Failure Process ◽

Damage Model ◽

Maximum Load ◽

Initiation Toughness ◽

Concrete Fracture ◽

Three Point Bending ◽

Finite Element Software ◽

Fracture Failure ◽

Accumulation Of Damage

Taking into account the initial damage and the accumulation of damage of concrete, Mazars damage model was modified. Based on the modified Mazars damage model, combined with finite element software ANSYS, the fracture failure process of the three-point bending notched beam of concrete was simulated. The initiation load Pini and maximum load Pmax of the three-point bending beam were determined with the damage criterion, and the full relation curve of the load P versus the loading point displacement Δ of the fracture failure process of the three-point bending beam was obtained. The results show that the method of numerical simulation of concrete fracture failure process is feasible, and based on the initiation load of the crack determined by numerical simulation, the initiation toughness of the beam can be easily calculated, and the problem of calculation of the initiation toughness caused by the initiation load can not be accurately determined in the actual experiment is resolved.

Download Full-text

The Progressive Failure Analysis of Uni-Directional Fibre Reinforced Composite Laminates

Journal of Mechanics ◽

10.1017/jmech.2019.55 ◽

2020 ◽

Vol 36 (2) ◽

pp. 159-166

Author(s):

T. Yi

Keyword(s):

Composite Laminates ◽

Progressive Failure ◽

Failure Process ◽

Damage Model ◽

Three Dimensional ◽

Dissipated Energy ◽

Solid Element ◽

Reinforced Composite ◽

Shear Rupture ◽

Composite Solid

ABSTRACTThe three dimensional standard damage model developed by Lavedeze et.al [9, 13] for uni-directional fibre reinforced ply is implemented into the nonlinear solution of NX Nastran within composite solid element to analyze the progressive damage process and ultimate failure of fibre reinforced composite laminates. This ply level meso-damage-constitutive-model takes into account main damage mechanisms including fibre breaking, matrix transverse cracking, and fibre/matrix de-bonding; also considers contributions like plasticity coupling, damage delay effects, and elastic nonlinearity in fibre compression. Dissipated energy and damage status are also introduced to reflect the damage condition on the macrostructural-level. Using the implemented code, simulation is carried out on the uniaxial tension of a [±45]2s laminate with IM6/914 material, wherein the predicted ply shear rupture stress matches the experimental results very well and better than the theoretical predictions in literature. Moreover, a [-45/0/45/90] holed laminate loaded in tension is simulated to show the complex behavior of subcritical damage evolution and failure process in the composite structure. The composite solid element with damage model supported in NX Nastran is shown to be a reliable tool to analyze the progressive failure of uni-directional fibre reinforced composite laminates.

Download Full-text

A Continuum Damage Model for Intralaminar Progressive Failure Analysis of CFRP Laminates Based on the Modified Puck’s Theory

Materials ◽

10.3390/ma12203292 ◽

2019 ◽

Vol 12 (20) ◽

pp. 3292

Author(s):

Gu ◽

Li ◽

Keyword(s):

Coordinate System ◽

Progressive Failure ◽

Failure Process ◽

Damage Model ◽

Fracture Plane ◽

Continuum Damage ◽

Fiber Fracture ◽

Continuum Damage Model ◽

Cfrp Laminates ◽

Damage Initiation

A continuum damage model is proposed to predict the intralaminar progressive failure of CFRP laminates based on the modified Puck’s theory. Puck’s failure criteria, with consideration of the in situ strength effect, are employed to evaluate the onset of intralaminar failure including fiber fracture and inter-fiber fracture. After damage initiation, a bilinear constitutive relation is used to describe the damage evolution process. In strict accordance with Puck’s concept of action plane, the extent of damage is quantified by the damage variables defined in the fracture plane coordinate system, rather than the traditional material principal coordinate system. Theoretical and experimental evaluation of CFRP laminates under different loading conditions demonstrates the rationality and effectiveness of the proposed numerical model. The model has been successfully implemented in a finite element (FE) software to simulate the intralaminar progressive failure process of CFRP laminates. A good agreement between the experimental and numerical results demonstrates that the present model is capable of predicting the intralaminar failure of CFRP laminates.

Download Full-text

3D Anisotropic Elastoplastic-Damage Model and its Application in Simulating the Behavior of Rock Materials

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.324-325.579 ◽

2006 ◽

Vol 324-325 ◽

pp. 579-582

Author(s):

Jun Feng Zhang ◽

Tao Qi

Keyword(s):

Damage Evolution ◽

Damage Mechanics ◽

Rock Sample ◽

Progressive Failure ◽

Failure Process ◽

Damage Model ◽

Tensor Decomposition ◽

Continuum Damage Mechanics ◽

Proposed Model ◽

Elastoplastic Damage

A 3D anisotropic elastoplastic-damage model was presented based on continuum damage mechanics theory. In this model, the tensor decomposition technique is employed. Combined with the plastic yield rule and damage evolution, the stress tensor in incremental format is obtained. The derivate eigenmodes in the proposed model are assumed to be related with the uniaxial behavior of the rock material. Each eigenmode has a corresponding damage variable due to the fact that damage is a function of the magnitude of the eigenstrain. Within an eigenmodes, different damage evolution can be used for tensile and compressive loadings. This model was also developed into finite element code in explicit format, and the code was integrated into the well-known computational environment ABAQUS using the ABAQUS/Explicit Solver. Numerical simulation of an uniaxial compressive test for a rock sample is used to examine the performance of the proposed model, and the progressive failure process of the rock sample is unveiled.

Download Full-text

The meso-failure mechanism of lightweight concrete simulated by the phase field method

Engineering Computations ◽

10.1108/ec-10-2020-0564 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Jichang Wang ◽

Xiaoming Guo

Keyword(s):

Crack Propagation ◽

Phase Field ◽

Lightweight Concrete ◽

Volume Fraction ◽

Failure Process ◽

Damage Model ◽

Automatic Generation ◽

Phase Field Method ◽

Content Type ◽

Propagation Paths

PurposeA mesoscopic phase field (PF) model is proposed to simulate the meso-failure process of lightweight concrete.Design/methodology/approachThe PF damage model is applied to the meso-failure process of lightweight concrete through the ABAQUS subroutine user-defined element (UEL). And the improved staggered iteration scheme with a one-pass procedure is used to alternately solve the coupling equations.FindingsThese examples clearly show that the crack initiation of the lightweight concrete specimens mainly occurs in the ceramsite aggregates with weak strength, especially in the larger aggregates. The crack propagation paths of the specimens with the same volume fraction of light aggregates are completely different, but the crack propagation paths all pass through the ceramsite aggregates near the cracks. The results also showed that with the increase in the volume fractions of the aggregates, the slope and the peak loads of the force-deflection (F-d) curves gradually decrease, the load-bearing capacity of the lightweight concrete specimens decreases, and crack branching and coalescence are less likely during crack propagation.Originality/valueThe mesostructures with a mortar matrix, aggregates and an interfacial transition zone (ITZ) are generated by an automatic generation and placement program, thus incorporating the typical three-phase characteristics of lightweight concrete into the PF model.

Download Full-text

A Phase-Field Damage Model for Orthotropic Materials and Delamination in Composites

Journal of Applied Mechanics ◽

10.1115/1.4038506 ◽

2017 ◽

Vol 85 (1) ◽

Cited By ~ 9

Author(s):

Bensingh Dhas ◽

Md. Masiur Rahaman ◽

Kiran Akella ◽

Debasish Roy ◽

J. N. Reddy

Keyword(s):

Phase Field ◽

Present Method ◽

Damage Model ◽

Superior Performance ◽

Orthotropic Materials ◽

Virtual Power ◽

Governing Equations ◽

Cohesive Law ◽

Small Deviations ◽

Crack Faces

A phase-field damage model for orthotropic materials is proposed and used to simulate delamination of orthotropic laminated composites. Using the deviatoric and hydrostatic tensile components of the stress tensor for elastic orthotropic materials, a degraded elastic free energy that can accommodate damage is derived. The governing equations follow from the principle of virtual power and the resulting damage model, by its construction, conforms with the physical relevant condition of no matter interpenetration along the crack faces. The model also dispenses with the traction separation law, an extraneous hypothesis conventionally brought in to model the interlaminar zones. The model is assessed through numerical simulations on delaminations in mode I, mode II, and another such problem with multiple initial notches. The present method is able to reproduce nearly all the features of the experimental load displacement curves, allowing only for small deviations in the softening regime. Numerical results also show forth a superior performance of the proposed method over existing approaches based on a cohesive law.

Download Full-text

RESPONSE AND DAMAGE EVOLUTION OF SINGLE EDGE NOTCHED TIMBER BEAMS UNDER THREE-POINT BENDING

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2020.26.0094 ◽

2020 ◽

Vol 26 ◽

pp. 94-99

Author(s):

Eliška Šmídová ◽

Petr Kabele ◽

Michal Šejnoha

Keyword(s):

Damage Evolution ◽

Image Correlation ◽

Single Edge ◽

Crack Tip Opening Displacement ◽

Opening Displacement ◽

Three Point Bending ◽

Single Edge Notch ◽

Failure Patterns ◽

Edge Notch ◽

Timber Beams

Two groups of small-size single edge notched beams (SENB) made of European spruce (Picea abies) were tested in three-point bending (3PB) until failure under displacement control. The first group comprised of eight solid and two glued laminated (GL) timber beams manufactured with (a) the single edge notch at the bottom of the mid-span and (b) the reduced ligament depth. The second group consisted of four GL timber beams with the single edge notch only. We employed digital image correlation (DIC) to quantify strains and displacements, capture the damage evolution, and track the sequence of failure patterns. In this work, we present response of the beams in terms of load vs. crosshead displacement of the moving crosshead and load vs. crack tip opening displacement (CTOD).

Download Full-text

A Quasi-Brittle damage model in the framework of Bond-based Peridynamics with Adaptive Dynamic Relaxation method

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.15.4.2021.14.0680 ◽

2021 ◽

Vol 15 (4) ◽

pp. 8617-8623

Author(s):

H.N. Yakin ◽

Nik Abdullah Nik Mohamed ◽

M.R.M. Rejab

Keyword(s):

Progressive Failure ◽

Failure Process ◽

Damage Model ◽

Relaxation Method ◽

Static Problem ◽

Local Theory ◽

Physical Interaction ◽

Dynamic Relaxation ◽

Adaptive Dynamic ◽

Damage Models

Peridynamics (PD) is a new tool, based on the non-local theory for modelling fracture mechanics, where particles connected through physical interaction used to represent a domain. By using the PD theory, damage or crack in a material domain can be shown in much practical representation. This study compares between Prototype Microelastic Brittle (PMB) damage model and a new Quasi-Brittle (QBR) damage model in the framework of the Bond-based Peridynamics (BBPD) in terms of the damage plot. An in-house code using Matlab was developed for BBPD with inclusion of both damage models, and tested for a quasi-static problem with the implementation of Adaptive Dynamic Relaxation (ADR) method in the theory in order to get a faster steady state solutions. This paper is the first attempt to include ADR method in the framework of BBPD for QBR damage model. This paper analysed a numerical problem with the absence of failure and compared the displacement with literature result that used Finite Element Method (FEM). The obtained numerical results are in good agreement with the result from FEM. The same problem was used with the allowance of the failure to happen for both of the damage models; PMB and QBR, to observe the damage pattern between these two damage models. PMB damage model produced damage value of roughly twice compared to the damage value from QBR damage model. It is found that the QBR damage model with ADR under quasi-static loading significantly improves the prediction of the progressive failure process, and managed to model a more realistic damage model with respect to the PMB damage model.

Download Full-text

A mode I crack with multiple islands of ideal contact between the crack faces: An asymptotic model

Mathematics and Mechanics of Solids ◽

10.1177/10812865211021456 ◽

2021 ◽

pp. 108128652110214

Author(s):

Ivan Argatov

Keyword(s):

Crack Opening ◽

Reduction Factor ◽

Mode I ◽

Asymptotic Model ◽

Mode I Crack ◽

Opening Displacement ◽

Multiple Contacts ◽

Scaling Hypothesis ◽

Penny Shaped Crack ◽

Crack Faces

The problem of a mode I crack having multiple contacts between the crack faces is considered. In the case of small contact islands of arbitrary shapes, which are arbitrarily located inside the crack, the first-order asymptotic model for the crack opening displacement is constructed using the method of matched asymptotic expansions. The case of a penny-shaped crack has been studied in detail. A scaling hypothesis for the compliance reduction factor is formulated.

Download Full-text

A Modified Phase-Field Damage Model for Metal Plasticity at Finite Strains: Numerical Development and Experimental Validation

Metals ◽

10.3390/met11010047 ◽

2020 ◽

Vol 11 (1) ◽

pp. 47

Author(s):

Jelena Živković ◽

Vladimir Dunić ◽

Vladimir Milovanović ◽

Ana Pavlović ◽

Miroslav Živković

Keyword(s):

Phase Field ◽

Damage Evolution ◽

Deformation Gradient ◽

Damage Model ◽

Steel Structures ◽

Plasticity Model ◽

Metal Plasticity ◽

Damage And Fracture ◽

Von Mises ◽

Von Mises Plasticity

Steel structures are designed to operate in an elastic domain, but sometimes plastic strains induce damage and fracture. Besides experimental investigation, a phase-field damage model (PFDM) emerged as a cutting-edge simulation technique for predicting damage evolution. In this paper, a von Mises metal plasticity model is modified and a coupling with PFDM is improved to simulate ductile behavior of metallic materials with or without constant stress plateau after yielding occurs. The proposed improvements are: (1) new coupling variable activated after the critical equivalent plastic strain is reached; (2) two-stage yield function consisting of perfect plasticity and extended Simo-type hardening functions. The uniaxial tension tests are conducted for verification purposes and identifying the material parameters. The staggered iterative scheme, multiplicative decomposition of the deformation gradient, and logarithmic natural strain measure are employed for the implementation into finite element method (FEM) software. The coupling is verified by the ‘one element’ example. The excellent qualitative and quantitative overlapping of the force-displacement response of experimental and simulation results is recorded. The practical significances of the proposed PFDM are a better insight into the simulation of damage evolution in steel structures, and an easy extension of existing the von Mises plasticity model coupled to damage phase-field.

Download Full-text