Damage Analysis and Numerical Simulation for Failure Process of Extra-Long Pre-Stressed Concrete Beams

2011 ◽  
Vol 368-373 ◽  
pp. 1318-1322
Author(s):  
Jian Yuan ◽  
Wen Gang Zhu ◽  
Min Chen
Keyword(s):  
Damage Mechanics ◽  
Concrete Beams ◽  
Failure Process ◽  
Damage Model ◽  
Mechanics Model ◽  
Damage And Fracture ◽  
Tension And Compression ◽  
Damage Constitutive Model ◽  
Damage Theory ◽  
Elastic Damage

The failure process for an extra-long pre-stressed concrete beam under static loads was simulated based on the elastic damage theory with the commercial software ABAQUS. By taking account of the different damage behaviors of concrete under tension and compression conditions, a damage mechanics model with three independent parameters was derived from the elastic damage theory. By combining the proposed damage model with the ABAQUS, the damage model was added to UMAT user subroutine. This method was developed to analyze the failure process of the extra-long pre-stressed concrete beams. The theoretical results show that the proposed damage constitutive model can be applied to describe the damage and fracture behaviors of the extra-long pre-stressed concrete beams.

Fatigue-Cumulative Damage Model of RC Crane Girders Strengthened with FRP Strips

2008 ◽  
Vol 385-387 ◽  
pp. 165-168
Author(s):  
Shan Suo Zheng ◽  
Bin Wang ◽  
Lei Li ◽  
Liang Zhang ◽  
Pi Ji Hou
Keyword(s):  
Damage Mechanics ◽  
Flexural Rigidity ◽  
Failure Process ◽  
Damage Model ◽  
Cumulative Damage ◽  
Good Time ◽  
Failure Patterns ◽  
Damage And Fracture ◽  
Cumulative Damage Model ◽  
Frp Strips

The cumulative damage of the reinforced concrete (RC) crane girders occurred by overload, fatigue and other reasons in service may deteriorate the safety of RC crane girders seriously, so it is necessary to analyze the damage mechanism and rationally reinforce them in good time. In this paper, RC crane girder strengthened with CFRP strips is taken as a target, and the mechanical performance degradation under fatigue load is studied. According to the basic theory of continuum damage mechanics, a damage variable is defined by flexural rigidity, and fatigue- cumulative damage model, which describes the process of damage and fracture, is established. The variation law of cumulative damage of RC crane girders strengthened with FRP strips under crane load is discussed, and the failure patterns such as concrete cracking, debonding between CFRP strips and concrete, yield of steel bars etc., are studied. The criterion which can be used to estimate the cumulative damage degree of strengthened RC crane girders is proposed. Finally, the evolution of the fatigue damage in the RC crane girders strengthened with CFRP strips is numerically simulated, and the results show that the proposed model can correctly describe the damage and failure process of strengthened RC crane girders. The research will provide a reference for the damage analysis and reinforcement of RC crane girders strengthened with CFRP strips.

Modelling the asymmetric tension–compression properties of additively manufactured alloys using continuum damage mechanics

2021 ◽  
pp. 146442072110134
Author(s):  
A Nayebi ◽  
H Rokhgireh ◽  
M Araghi ◽  
M Mohammadi
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Element Model ◽  
Continuum Damage ◽  
Compression Tests ◽  
Compression Properties ◽  
Mechanics Model ◽  
Stress Components ◽  
Tension And Compression ◽  
Closure Effect

Additively manufactured parts often comprise internal porosities due to the manufacturing process, which needs to be considered in modelling their mechanical behaviour. It was experimentally shown that additively manufactured parts’ tensile and compressive mechanical properties are different for various metallic alloys. In this study, isotropic continuum damage mechanics is used to model additively manufactured alloys’ tension and compression behaviours. Compressive stress components can shrink discontinuities present in additively manufactured alloys. Therefore, the crack closure effect was employed to describe different behaviours during uniaxial tension and compression tests. A finite element model embedded in an ABAQUS’s UMAT format was developed to account for the isotropic continuum damage mechanics model. The numerical results of tension and compression tests were compared with experimental observations for additively manufactured maraging steel, AlSi10Mg and Ti-6Al-4V. Stress–strain curves in tension and compression of these alloys were obtained using the continuum damage mechanics model and compared well with the experimental results.

Further Development of the Nonlocal Damage Model of Rousselier for the Transition Regime of Fracture Toughness and Different Stress States

2014 ◽  
Author(s):  
Sarah Gehrlicher ◽  
Michael Seidenfuss ◽  
Xaver Schuler
Keyword(s):  
Fracture Toughness ◽  
Damage Mechanics ◽  
Damage Model ◽  
Nonlocal Damage ◽  
Brittle Transition ◽  
Mechanics Model ◽  
Element Size ◽  
Transition Area ◽  
Ductile To Brittle Transition ◽  
Stress States

In nuclear power engineering failure has to be excluded for components with high safety relevance. Currently, safety assessments mainly use fracture mechanics concepts. Especially in the transition region of fracture toughness where limited stable crack extension may appear before cleavage fracture the currently applied methods are limited. This Paper deals with the development and verification of a closed concept for safety assessment of components over the whole range from the lower shelf to the upper shelf of fracture toughness. The results of classical used local damage mechanics models depend on the element size of the numerical model. This disadvantage can be avoided using an element size depending on microstructure. With high stress gradients and small crack growth rates usually smaller elements are required. This is in conflict with an element size depending on microstructure. By including the damage gradient as an additional degree of freedom in the damage mechanics model the results depend no longer at the element size. In the paper damage mechanics computations with a nonlocal formulation of the Rousselier model are carried out for the evaluation of the upper transition area. For the prediction of fracture toughness from the ductile to brittle transition area the nonlocal Rousselier model is coupled with the Beremin model. Thus ductile crack growth and failure by brittle fracture can be described in parallel. The numerical prediction of the behaviour of fracture toughness specimens (C(T)-specimens and SE(B)-specimens with and without side grooves) and the experimental results are highly concordant. The load displacement behavior of the specimens and the developed crack front from the ductile to brittle transition area can be well calculated with the nonlocal damage model. The instability in relation to temperature calculated with the coupled damage mechanics model predicts the variations of the experimental results very well. For further application of the nonlocal Rousselier model experiments and numerical calculations of specimens with different stress states and multi-axiality are carried out. Modified fracture toughness specimens like CTS-specimens (compact tension shear specimens) are taken to investigate the applicability of the nonlocal damage model of Rousselier to mixed mode fracture.

Numerical Simulation of Gun Bore Damage during Engraving Process of Driving Band

2017 ◽  
Vol 1142 ◽  
pp. 363-366
Author(s):  
He Yang Sun ◽  
Chang Zhi Jia ◽  
Yao Xin He ◽  
Tian Xiao Cui
Keyword(s):  
Damage Mechanics ◽  
Failure Process ◽  
Damage Model ◽  
Firing Process ◽  
Computation Method ◽  
Damage Behavior ◽  
Damage And Failure ◽  
Gun Barrel ◽  
Safety Design ◽  
Microscopic Damage

A Damage mechanics finite element numerical computation method was established based on HLC microscopic damage model to solve the problem of damage, crack initialization and growth inside bore during the firing process. The damage and failure process of the bore surface was simulated numerically during multiple rounds of firing. The law of the barrel material performance changing with the number of firing rounds was analyzed during the engraving process of the driving band and compared with the experimental results. It is proved that HLC microscopic damage model can show the complicate damage behavior and predict the cracking defect, which provides a reference for safety design of the gun barrel.

Statistical Damage Constitutive Model for Concrete under Biaxial Tension

2013 ◽  
Vol 438-439 ◽  
pp. 183-186
Author(s):  
Wei Feng Bai ◽  
Jun Hong Zhang ◽  
Jun Feng Guan ◽  
Ying Cui
Keyword(s):  
Constitutive Model ◽  
Biaxial Tension ◽  
Damage Model ◽  
Damage Mechanism ◽  
Deformation Properties ◽  
Damage Constitutive Model ◽  
Strength And Deformation ◽  
Statistical Damage Constitutive Model ◽  
Damage Theory ◽  
Statistical Damage

Based on the statistical damage theory and the experimental phenomena, the statistical damage constitutive model for concrete under biaxial tension is proposed. The two meso-scale damage modes, rupture and yield are considered, and the whole damage evolution process is driven by the principal tensile damage strain. The results show that the proposed statistical damage model can accurately predict the constitutive behavior in the uniform damage phase for concrete under biaxial tension. The damage mechanism is discussed in the view point of biaxial strength and deformation properties.

scholarly journals Computational Modelling of Fracture Propagation in Rocks Using a Coupled Elastic-Plasticity-Damage Model

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Isa Kolo ◽  
Rashid K. Abu Al-Rub ◽  
Rita L. Sousa
Keyword(s):  
Constitutive Model ◽  
Damage Model ◽  
Computational Modelling ◽  
Fracture Propagation ◽  
Material Model ◽  
Model Predictions ◽  
Tension And Compression ◽  
Damage Constitutive Model ◽  
Ak Model ◽  
Spatially Varying

A coupled elastic-plasticity-damage constitutive model, AK Model, is applied to predict fracture propagation in rocks. The quasi-brittle material model captures anisotropic effects and the distinct behavior of rocks in tension and compression. Calibration of the constitutive model is realized using experimental data for Carrara marble. Through the Weibull distribution function, heterogeneity effect is captured by spatially varying the elastic properties of the rock. Favorable comparison between model predictions and experiments for single-flawed specimens reveal that the AK Model is reliable and accurate for modelling fracture propagation in rocks.

scholarly journals Numerical analysis of steel-fiber-reinforced concrete beams using damage mechanics

2016 ◽  
Vol 9 (2) ◽  
pp. 153-191
Author(s):  
W. M. Pereira Junior ◽  
D. L. Araújo ◽  
J. J. C. Pituba
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Behavior ◽  
Damage Mechanics ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Damage Model ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

ABSTRACT This work deals with numerical modeling of the mechanical behavior of steel-fiber-reinforced concrete beams using a constitutive model based on damage mechanics. Initially, the formulation of the damage model is presented. The concrete is assumed to be an initial elastic isotropic medium presenting anisotropy, permanent strains, and bimodularity induced by damage evolution. In order to take into account the contribution of the steel fiber to the mechanical behavior of the media, a homogenization procedure is employed. Finally, numerical analyses of steel-fiber-reinforced concrete beams submitted to bending loading are performed in order to show the good performance of the model and its potential.

Study on Damage Evolution Mechanism of Concrete under Uniaxial Tension

2012 ◽  
Vol 238 ◽  
pp. 46-50
Author(s):  
Wei Feng Bai ◽  
Ying Cui ◽  
Qian Wang ◽  
Jun Feng Guan ◽  
Jian Wei Zhang
Keyword(s):  
Uniaxial Tension ◽  
Damage Mechanics ◽  
Failure Process ◽  
Damage Model ◽  
Damage Mechanism ◽  
Deformation Characteristics ◽  
Deformation And Failure ◽  
Damage And Failure ◽  
Basic Parameters ◽  
Fundamental Research

The damage and failure mechanism of quasi-brittle materials is the most fundamental research topic in Damage Mechanics. In this paper, the mesoscopic damage mechanism of concrete under uniaxial tension was discussed. The rupture and yield damage modes in meso-scale were introduced as the two basic parameters to define the damage accumulated variable. The results show that the proposed statistical damage model can accurately predict the whole deformation and failure process of concrete under uniaxial tension, including the two-stage deformation characteristics and the size effect.

Elastic Ply Damage Mechanics Modeling of Glass/Epoxy Laminated Composite

2013 ◽  
Vol 683 ◽  
pp. 176-181
Author(s):  
Yong Chen ◽  
Bao Jun Pang ◽  
Wei Zheng
Keyword(s):  
Composite Material ◽  
Damage Mechanics ◽  
Epoxy Composite ◽  
Damage Model ◽  
Laminated Composite ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Tensile Shear ◽  
Mechanics Model ◽  
Input Parameters

In order to establish an elastic damage model for S2-glass/epoxy composite and identify the input parameters, in-plane behaviour of the composite including tensile, compression and tensile shear were investigated through series of tests. Concerning no plasticity, a simple elastic ply damage mechanics model for this composite was characterized based on Continuum Damage Mechanics Model (CDM) and the input parameters were obtained. The model was then implemented into ABAQUS/EXPLICT and the results show the model can capture most of the in-plane behaviour of the composite material.

scholarly journals Quantitative Damage and Fracture Mode of Sandstone under Uniaxial Load Based on Acoustic Emission

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Ying Xu ◽  
Qiangqiang Zheng ◽  
Xin Gao ◽  
Rongzhou Yang ◽  
Xian Ni ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Mechanism ◽  
Damage Mechanics ◽  
Shear Failure ◽  
Rock Fracture ◽  
Damage Model ◽  
Damage Models ◽  
Uniaxial Load ◽  
Damage And Fracture ◽  
Ae Signals

The damage degree and fracture mechanism of the rock are important to the bearing performance of the rock mass and the stability of the overlying structure. Most of the existing damage models for characterizing rock damage exclude the range of postpeak stress or do not consider the compaction and closure stage of the fracture, and the description of the quantitative damage of sandstone is not accurate enough. In addition, the description of the rock fracture mechanism under load is not exact enough. Aiming at the problem of quantitative damage and fracture mechanism of the loaded rock, this paper adopts acoustic emission (AE) to monitor the loading process of sandstone under uniaxial loading. In accordance with the characteristics of the AE signal, the loading stage of sandstone under uniaxial load is divided into three stages: initial hit stage, hit stability stage, and hit instability stage. By modifying the traditional damage model and combining the AE signals of the sandstone under the load, a modified damage mechanics model is obtained, which can fully express the entire loading stage. Furthermore, through the analysis of AE signals, the fracture mechanism of sandstone under uniaxial load is studied. The results show that the modified damage model can quantitatively describe the damage at different loading stages which include two areas including the fracture compaction closure stage and the postpeak stress stage. The failure and instability of sandstone under uniaxial load is mainly shear failure. The research results can provide a reference for the nondestructive testing of sandstone and engineering reliability in geotechnical engineering.

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