scholarly journals Combined Numerical-Statistical Analyses of Damage and Failure of 2D and 3D Mesoscale Heterogeneous Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Xiaofeng Wang ◽  
Andrey P. Jivkov
Keyword(s):  
Cohesive Zone Model ◽  
Volume Fraction ◽  
Simulation Method ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Zone Model ◽  
Generation Process ◽  
Cohesive Elements ◽  
Damage And Failure ◽  
2D And 3D

Generation and packing algorithms are developed to create models of mesoscale heterogeneous concrete with randomly distributed elliptical/polygonal aggregates and circular/elliptical voids in two dimensions (2D) or ellipsoidal/polyhedral aggregates and spherical/ellipsoidal voids in three dimensions (3D). The generation process is based on the Monte Carlo simulation method wherein the aggregates and voids are generated from prescribed distributions of their size, shape, and volume fraction. A combined numerical-statistical method is proposed to investigate damage and failure of mesoscale heterogeneous concrete: the geometrical models are first generated and meshed automatically, simulated by using cohesive zone model, and then results are statistically analysed. Zero-thickness cohesive elements with different traction-separation laws within the mortar, within the aggregates, and at the interfaces between these phases are preinserted inside solid element meshes to represent potential cracks. The proposed methodology provides an effective and efficient tool for damage and failure analysis of mesoscale heterogeneous concrete, and a comprehensive study was conducted for both 2D and 3D concrete in this paper.

scholarly journals COMPUTATION FOR THE DELAMINATION IN THE LAMINATE COMPOSITE MATERIAL USING A COHESIVE ZONE MODEL BY ABAQUS

2020 ◽  
Vol 57 (6A) ◽  
pp. 61
Author(s):  
Hoa Cong Vu
Keyword(s):  
Finite Element ◽  
Cohesive Zone Model ◽  
Constitutive Relations ◽  
Damage Zone ◽  
Damage Model ◽  
Zone Model ◽  
Element Formulation ◽  
Cohesive Elements ◽  
Element Mesh ◽  
Variable Mode

In this paper, a damage model using cohesive damage zone for the simulation of progressive delamination under variable mode is presented. The constitutive relations, based on liner softening law, are using for formulation of the delamination onset and propagation. The implementation of the cohesive elements is described, along with instructions on how to incorporate the elements into a finite element mesh. The model is implemented in a finite element formulation in ABAQUS. The numerical results given by the model are compare with experimental data

Investigation on the Load Capacity and Failure Process of T-Joint by Experiments and Numerical Method

2011 ◽  
Vol 328-330 ◽  
pp. 1317-1321
Author(s):  
Ping Hu ◽  
Qi Shao ◽  
Qian Nie ◽  
Wei Dong Li
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Load Capacity ◽  
Failure Process ◽  
Adhesive Layer ◽  
Zone Model ◽  
T Joints ◽  
Damage And Failure ◽  
Automotive Structures ◽  
In The Beginning

Adhesive bonded T-joint is commonly applied in the manufacture of automotive structures. The objective of this work is the analysis of the load capacity of the adhesive-bonded T-joints under tension load and the influence causing by some parameters of adherend on the damage of T-joint. Thus, a series of tests were carried out and the balanced joint and the imbalanced joint concepts were proposed to illustrate the influence. And the results show that the imbalanced joints suffered greater stress concentration than the balanced one. Furthermore, by increasing the stiffness of adherends , one can increase the load capacity of a balanced joint. Meanwhile, in order to simulate the damage and failure processes in this type of joint, the cohesive zone model (CZM) based analysis was carried out using finite element method in ABAQUS. One can observed that only the upper end of adhesive layer transmits the load in the beginning.

scholarly journals COMPUTATION FOR THE DELAMINATION IN THE LAMINATE COMPOSITE MATERIAL USING A COHESIVE ZONE MODEL BY ABAQUS

2020 ◽  
Vol 57 (6A) ◽  
pp. 61
Author(s):  
Hoa Cong Vu
Keyword(s):  
Finite Element ◽  
Cohesive Zone Model ◽  
Constitutive Relations ◽  
Damage Zone ◽  
Damage Model ◽  
Zone Model ◽  
Element Formulation ◽  
Cohesive Elements ◽  
Element Mesh ◽  
Variable Mode

In this paper, a damage model using cohesive damage zone for the simulation of progressive delamination under variable mode is presented. The constitutive relations, based on liner softening law, are using for formulation of the delamination onset and propagation. The implementation of the cohesive elements is described, along with instructions on how to incorporate the elements into a finite element mesh. The model is implemented in a finite element formulation in ABAQUS. The numerical results given by the model are compare with experimental data

scholarly journals Study on Shear Mechanism of Bolted Jointed Rocks: Experiments and CZM-Based FEM Simulations

2019 ◽  
Vol 10 (1) ◽  
pp. 62 ◽  
Author(s):  
Shubo Zhang ◽  
Gang Wang ◽  
Yujing Jiang ◽  
Xianlong WU ◽  
Genxiao Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Failure Mechanism ◽  
Laboratory Experiments ◽  
Shear Failure ◽  
Cohesive Zone Model ◽  
Rock Fracture ◽  
High Strength ◽  
Simulation Method ◽  
Jointed Rock ◽  
Zone Model

Based on the underground jointed rock of the Huangdao water sealed oil depot in China, the shear failure mechanism of bolted jointed rock is studied through laboratory experiments and numerical simulation. Laboratory experiments are performed to explore the shear behavior of bolted jointed rock with different joint roughness. Our results show that using high strength bolts is beneficial to improving the shear strength of the jointed rock, but the high strength of bolts can also lead to the rock fracture, which should be avoided. For this particular project site, experimental results indicate that 15% elongation is the best. In addition, a new numerical simulation method with CZM (cohesive zone model) used for modeling the shearing process of bolted jointed rock is proposed. It can reasonably describe the characteristics of jointed rock as a discontinuous medium, and bolt as a continuous medium, that replicate well the shearing process. The numerical model is then verified by comparing the experiment results, and it can be effectively be applied to the simulation of joint shearing process. Finally, we use this simulation method to explore the shear failure mechanism of bolted joints, and find that the root cause of rock failure is the deformation mismatch between the bolt and the surrounding rock. The tensile stress between them eventually causes the rock to fracture near the bolt hole.

The Research of the Effective Moduli of Particle Reinforced Polymer Composites Based on Interface Debonding

2009 ◽  
Vol 413-414 ◽  
pp. 211-217
Author(s):  
Xin Long Chang ◽  
Bin Jian ◽  
Chang Ouyang
Keyword(s):  
Polymer Composites ◽  
Cohesive Zone Model ◽  
Volume Fraction ◽  
Micromechanical Model ◽  
Interface Debonding ◽  
Zone Model ◽  
Effective Moduli ◽  
Reinforced Polymer ◽  
The Matrix ◽  
Particulate Size

This paper is devoted to studying influences of matrix/particle interface debonding and particulate size in micromechanical predictions of the effective moduli of particulate reinforced polymer composites (PRPC). The PRPC is regarded as a three-phase composite that includes the matrix, particle and interphase. The formulation for the effective moduli of the interphase is derived by the cohesive zone model, and combined with the Mori-Tanaka method, the micromechanical model for the effective moduli of the PRPC is formulated with emphasis on the effects of the matrix/particle interface, particulate size and volume fraction. The numerical example shows that the interface debonding, the particulate size and volume fraction have significant influences on the effective moduli of PRPC. The effective moduli of the PRPC can be used to characterize its damage degree.

scholarly journals Fracture Behaviour of Real Coarse Aggregate Distributed Concrete under Uniaxial Compressive Load Based on Cohesive Zone Model

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4314
Author(s):  
Jingwei Ying ◽  
Jin Guo
Keyword(s):  
Finite Element ◽  
Uniaxial Compression ◽  
Digital Image ◽  
Cohesive Zone Model ◽  
Compressive Load ◽  
Strain Ratio ◽  
Image Correlation ◽  
Zone Model ◽  
Cohesive Elements ◽  
Compression Loading

Two-dimensional meso-scale finite element models with real aggregates are developed using images obtained by digital image processing to simulate crack propagation processes in concrete under uniaxial compression loading. The finite element model is regarded as a three-phase composite material composed of aggregate, mortar matrix and interface transition zone (ITZ). Cohesive elements with traction–separation laws are used to simulate complex nonlinear fracture. During the experiment, digital image correlation (DIC) was used to obtain the deformation and cracks of the specimens at different loading stages. The concept of strain ratio is proposed to describe the effectiveness of simulation. Results show that the numerical strain ratio curve and stress–strain curves are both in good agreement with experimental data. The consistency between the cracks obtained by simulation and those obtained by DIC shows the good performance of cohesive elements as well as the effectiveness of simulation. In summary, the model is able to provide accurate predictions of the whole fracture process in concrete under uniaxial compression loading.

scholarly journals Study on Crack Development of Concrete Lining with Insufficient Lining Thickness Based on CZM Method

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7862
Author(s):  
Jian Liu ◽  
Xuesen Zhang ◽  
Gaohang Lv ◽  
Kang Wang ◽  
Bo Han ◽  
...  
Keyword(s):  
Cohesive Zone Model ◽  
Concrete Strength ◽  
Surrounding Rock ◽  
Crack Development ◽  
Concrete Lining ◽  
Failure Behavior ◽  
Zone Model ◽  
Cohesive Elements ◽  
Cracking Behavior ◽  
Operation Period

The most common structural defect of a tunnel in the operation period is the cracking of concrete lining. The insufficient thickness of tunnel lining is one of the main reasons for its cracking. This study studied the cracking behavior of standard concrete specimens and the failure behavior of tunnel structures caused by insufficient lining thickness using Cohesive Zone Model (CZM). Firstly, zero-thickness cohesive elements were globally inserted between solid elements of the standard concrete specimen model, and the crack development process of different concrete grades was compared. On this basis, a three-dimensional numerical model of the tunnel in the operation period was established. The mechanism and characteristics of crack propagation under different lining thicknesses were discussed. In addition, the statistics of cracks were made to discuss the development rules of lining cracks quantitatively. The results show that the CZM can reasonably simulate the fracture behavior of concrete. With the increase in concrete strength grade, the number of cohesive damaged elements and crack area increases. The insufficient lining thickness changes the lining stress distribution characteristics, reduces the lining structure’s overall safety, and leads to the cracking of the diseased area more easily. When surrounding rock does not contact the insufficient lining thickness, its influence on the structure is more evident than when surrounding rock fills the entire lining thickness. The number of cohesive damaged elements and the size of the crack area increases significantly.

scholarly journals Numerical Simulation of Fatigue Crack Growth Rate and Crack Retardation due to an Overload Using a Cohesive Zone Model

2014 ◽  
Vol 891-892 ◽  
pp. 777-783 ◽  
Author(s):  
Sarmediran Silitonga ◽  
Johan Maljaars ◽  
Frans Soetens ◽  
Hubertus H. Snijder
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Crack Tip ◽  
Zone Model ◽  
Cohesive Elements

In this work, a numerical method is pursued based on a cohesive zone model (CZM). The method is aimed at simulating fatigue crack growth as well as crack growth retardation due to an overload. In this cohesive zone model, the degradation of the material strength is represented by a variation of the cohesive traction with respect to separation of the cohesive surfaces. Simulation of crack propagation under cyclic loads is implemented by introducing a damage mechanism into the cohesive zone. Crack propagation is represented in the process zone (cohesive zone in front of crack-tip) by deterioration of the cohesive strength due to damage development in the cohesive element. Damage accumulation during loading is based on the displacements in the cohesive zone. A finite element model of a compact tension (CT) specimen subjected to a constant amplitude loading with an overload is developed. The cohesive elements are placed in front of the crack-tip along a pre-defined crack path. The simulation is performed in the finite element code Abaqus. The cohesive elements behavior is described using the user element subroutine UEL. The new damage evolution function used in this work provides a good agreement between simulation results and experimental data.

scholarly journals Modelling Microstructural Deformation and the Failure Process of Plastic Bonded Explosives Using the Cohesive Zone Model

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3661 ◽  
Author(s):  
Kaida Dai ◽  
Baodi Lu ◽  
Pengwan Chen ◽  
Jingjing Chen
Keyword(s):  
Mechanical Behavior ◽  
Cohesive Zone ◽  
Shear Failure ◽  
Cohesive Zone Model ◽  
Failure Process ◽  
Interface Debonding ◽  
Zone Model ◽  
Strain Rates ◽  
Cohesive Elements ◽  
Failure Evolution

A microstructure finite element method combining the cohesive zone model (CZM) is used to simulate the mechanical behavior, deformation, and failure of polymer-bonded explosive (PBX) 9501 under quasi-static loading. PBX 9501 consists of Cyclotetramethylene tetranitramine (HMX) filler particles with a random distribution packaged in a polymeric binder. The particle is treated as elastic and the binder as viscoelastic. Cohesive elements with a bilinear softening law are inserted into the particle/binder interface, the HMX particle, and the binder to study the interface’s debonding and failure evolution. Macroscopic stress–strain curves homogenized across the microstructure under tension and compression with different strain rates are basically consistent with the experimental data. The interface debonding approximately vertical to the loading direction is the primary failure mechanism under tension, while shear failure along the interfaces and particle fracture plays a significant role under compression. The effects of interface strengths and strain rates on the performance of PBX 9501 are also evaluated. The tensile and compressive strengths are dependent on the interface strength and strain rate, but the failure paths are insensitive. This model is shown to accurately predict macroscopic responses and improve our understanding of the relationship between the mechanical behavior and microstructure of PBX 9501.

Numerical Study on Effects of Interphase in Natural Short Fiber Reinforced Polymer Composite Based on Cohesive Zone Model

2013 ◽  
Vol 275-277 ◽  
pp. 1646-1649 ◽  
Author(s):  
Min Shen ◽  
Yan Li Duan ◽  
Yang Liu ◽  
Dong Chao Liang
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Numerical Study ◽  
Simulation Method ◽  
Short Fiber ◽  
Zone Model ◽  
Fiber Reinforced ◽  
Motor Industry ◽  
Reinforced Polymer ◽  
Three Phase

Natural short fiber reinforced polypropylene (PP) composite has great significance both in commercial and environmental and is widely used in motor industry. Its local inhomogeneity and interphase both affect the macroscopic properties of the composite. These phenomena are still difficult to observe and study accurately in the experiment. A cohesive zone model (CZM) based numerical simulation method is presented in this paper. The three-phase (matrix-interphase-fiber) model considering some different factors was developed to study the effects of interphase parameters on the mechanical properties of the composite.

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