Cohesive zone modeling of coupled buckling – Debond growth in metallic honeycomb sandwich structure

2012 ◽  
Vol 14 (6) ◽  
pp. 679-693 ◽  
Author(s):  
KC Gopalakrishnan ◽  
R Ramesh Kumar ◽  
S Anil Lal
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Interfacial Bond Strength ◽  
Tension Tests ◽  
Honeycomb Sandwich ◽  
Zone Modeling ◽  
Buckling Failure ◽  
Peel Tests

Buckling-induced skin–core debond growth in honeycomb sandwich cantilever beam is demonstrated using a cohesive zone model. The input parameters for the analysis are interfacial bond strength, mode I and mode II interfacial fracture toughness values, obtained from flatwise tension tests, drum-peel tests and three-point end notch flexure tests, respectively. Debonded honeycomb specimens are tested and the acoustic emission technique was used to observe the initiation of the debond growth. The load-displacement response from the cohesive zone model model shows a good agreement with the experimental results. The conventional analysis without cohesive zone model overestimates failure load by 56%. Cohesive zone model is able to predict the coupled debond growth and buckling failure in honeycomb sandwich structures.

Numerical Investigation of the Damage Behavior of S355 EBW by Cohesive Zone Modeling

2015 ◽  
Vol 1102 ◽  
pp. 149-153 ◽  
Author(s):  
H.Y. Tu ◽  
Ulrich Weber ◽  
Siegfried Schmauder
Keyword(s):  
Tensile Test ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Crack Opening ◽  
Compact Tension ◽  
Initial Crack ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Opening Displacement ◽  
Zone Modeling

In this paper, the cohesive zone model is used to study the fracture behavior of an electron beam welded (EBW) steel joint. Mechanical properties of different weld regions are derived from the tensile test results of flat specimens, which are obtained from the respective weld regions. Based on the tensile test of notched round specimens, the cohesive strength T0can be fixed. With the fixed T0value, the cohesive model is applied to compact tension (C(T)) specimens with the initial crack located at different positions of weldment with different cohesive energy values Γ0. Numerical simulations are compared with the experimental results in the form of force vs. Crack Opening Displacement (COD) curves as well as fracture resistance (JR) curves.

Comparison of Through-Wall and Complex Crack Behaviors in Dissimilar Metal Weld Pipe Using Cohesive Zone Modeling

2013 ◽  
Author(s):  
Do-Jun Shim ◽  
David Rudland ◽  
Frederick Brust
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Ductile Crack ◽  
Dissimilar Metal ◽  
Ductile Crack Growth ◽  
Zone Modeling ◽  
Dissimilar Metal Weld ◽  
Metal Weld

Cohesive zone modeling has been shown to be a convenient and effective method to simulate and analyze the ductile crack growth behavior in fracture specimens and structures. Recently, authors have applied the cohesive zone model to simulate the ductile fracture behavior of a through-wall cracked pipe test consisting of a single material. In this paper, cohesive zone modeling has been applied to simulate the ductile crack growth in dissimilar metal weld pipe tests that was recently conducted by the U.S. NRC. Two crack types, i.e. through-wall and complex cracks, were simulated in the work. This paper describes how the cohesive parameters were determined and discusses in detail about the finite element modeling of the cohesive zone model. Various fracture parameters were compared between the finite element analyses and the experiments to validate the model. The results of the cohesive zone models showed good agreement with the pipe test results. Furthermore, the results of the cohesive zone model demonstrate that the fracture toughness (J at crack initiation, Jinit.) of the complex cracked pipe can be significantly lower (factor of 0.41) than that of the through-wall cracked pipe.

Physics Based Formulation of a Cohesive Zone Model for Ductile Fracture

2015 ◽  
Vol 651-653 ◽  
pp. 993-999 ◽  
Author(s):  
Tuncay Yalcinkaya ◽  
Alan Cocks
Keyword(s):  
Ductile Fracture ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Volume Element ◽  
Cohesive Zone Modeling ◽  
Mode I ◽  
Zone Model ◽  
Metallic Materials ◽  
Bound Solution ◽  
Zone Modeling

This paper addresses a physics based derivation of mode-I and mode-II traction separation relations in the context of cohesive zone modeling of ductile fracture of metallic materials. The formulation is based on the growth of an array of pores idealized as cylinders which are considered as therepresentative volume elements. An upper bound solution is applied for the deformation of the representative volume element and different traction-separation relations are obtained through different assumptions.

Cohesive Zone Modeling for 3D Ductile Crack Propagation

2016 ◽  
Vol 853 ◽  
pp. 132-136 ◽  
Author(s):  
Xiao Li ◽  
Huang Yuan
Keyword(s):  
Crack Propagation ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Three Dimensional ◽  
Stress Triaxiality ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Ductile Materials ◽  
Zone Modeling ◽  
Good Agreement

Computational modeling of three-dimensional crack propagation in very ductile materials is still a challenge in fracture mechanics analysis. In the present work a new stress-triaxiality-dependent cohesive zone model (TCZM) is proposed to describe elastic-plastic fracture process in full three-dimensional specimens. The cohesive parameters are identified as a function of the stress triaxiality from ductile fracture experiments. The predictions of TCZM show good agreement with the experimental results for both side-grooved C(T) specimen and rod bar specimen.

Thermo-Mechanical Analysis of Mixed-Mode Damage: Cohesive Zone Modeling

2015 ◽  
Author(s):  
Hussain Altammar ◽  
Sudhir Kaul ◽  
Anoop Dhingra
Keyword(s):  
Cohesive Zone ◽  
Composite Beam ◽  
Mixed Mode ◽  
Cohesive Zone Model ◽  
Mechanical Load ◽  
Element Model ◽  
Mechanical Analysis ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Damage Initiation

Damage detection and diagnostics is a key area of research in structural analysis. This paper presents results from the analysis of mixed-mode damage initiation in a composite beam under thermal and mechanical loads. A finite element model in conjunction with a cohesive zone model (CZM) is used in order to determine the location of joint separation as well as the contribution of each mode in damage (debonding) initiation. The composite beam is modeled by using two layers of aluminum that are bonded together through a layer of adhesive. Simulation results show that the model can successfully detect the location of damage under a thermo-mechanical load. The model can also be used to determine the severity of damage due to a thermal load, a mechanical load and a thermo-mechanical load. It is observed that integrating thermal analysis has a significant influence on the fracture energy.

Multiscale cohesive zone modeling and simulation of high-speed impact, penetration, and fragmentation

2018 ◽  
Vol 03 (01n02) ◽  
pp. 1850003
Author(s):  
Chao Wang ◽  
Dandan Lyu
Keyword(s):  
Cohesive Zone ◽  
High Speed ◽  
Cohesive Zone Model ◽  
Bulk Material ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Spall Fracture ◽  
Weak Formulation ◽  
High Speed Impact ◽  
Different Characteristics

In this work, a multiscale cohesive zone model (MCZM) is developed to simulate the high-speed penetration induced dynamic fracture process such as fragmentation in crystalline solids. This model describes bulk material as a local quasi-continuum medium which follows the Cauchy–Born rule while cohesive zone element is governed by an interface depletion potential, such that the cohesive zone constitutive descriptions are genetically consistent with that of bulk element. This multiscale method proved to be effective in describing material inhomogeneities and it is constructed and implemented in a cohesive finite element Galerkin weak formulation. Numerical simulations of high-speed penetration with different shape of penetrators, i.e., square, circle and parabola nose penetrators are performed. Results show that the proposed MCZM can successfully capture spall fracture, the penetration process and different characteristics of fragmentation under different shape of penetrators.

Cohesive Zone Modeling of Stable Crack Propagation in Highly Ductile Steel

2018 ◽  
Vol 774 ◽  
pp. 167-172 ◽  
Author(s):  
Andreas Burgold ◽  
Stephan Roth ◽  
Meinhard Kuna
Keyword(s):  
Cohesive Zone ◽  
Large Scale ◽  
Cohesive Zone Model ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Minor Effect ◽  
Stable Crack Propagation ◽  
Wide Range ◽  
Separation Relation ◽  
A Minor

A recent cohesive zone model is applied to the simulation of crack extension in austenitic stainless steel under large scale yielding conditions. The shape of the corresponding exponential traction-separation-relation can be modified in a wide range. In order to investigate the sensitivity regarding the cohesive zone parameters, a systematic parametric study is performed. The shape of the traction-separation envelope has a minor effect on the results compared to the cohesive strength and the work of separation. The aim is to fit experimental data by an appropriate choice of these parameters. Therefore, not only force-displacement curves should be used, but also crack growth resistance curves should be employed. A promising strategy for parameter identification is derived.

Cohesive Zone Modeling of Mode I Fracture in Adhesive Bonded Joints

2007 ◽  
Vol 348-349 ◽  
pp. 13-16 ◽  
Author(s):  
Marco Alfano ◽  
Franco Furgiuele ◽  
A. Leonardi ◽  
Carmine Maletta ◽  
Glaucio H. Paulino
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Cohesive Zone Modeling ◽  
Mode I ◽  
Zone Model ◽  
Displacement Curve ◽  
Bonded Joints ◽  
Critical Energy Release Rate ◽  
Mode I Fracture ◽  
Adhesive Bonded Joints

This paper deals with the application of Cohesive Zone Model (CZM) concepts to study mode I fracture in adhesive bonded joints. In particular, an intrinsic piece-wise linear cohesive surface relation is used in order to model fracture in a pre-cracked bonded Double Cantilever Beam (DCB) specimen. Finite element implementation of the CZM is accomplished by means of the user element (UEL) feature available in the FE commercial code ABAQUS. The sensitivity of the cohesive zone parameters (i.e. fracture strength and critical energy release rate) in predicting the overall mechanical response is first examined; subsequently, cohesive parameters are tuned comparing numerical simulations of the load-displacement curve with experimental results retrieved from literature.

A Computational Model for Surface Welding in Covalent Adaptable Networks Using Finite-Element Analysis

2016 ◽  
Vol 83 (9) ◽  
Author(s):  
Kai Yu ◽  
Qian Shi ◽  
Tiejun Wang ◽  
Martin L. Dunn ◽  
H. Jerry Qi
Keyword(s):  
Finite Element ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Multiscale Model ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Shear Stresses ◽  
Self Healing ◽  
Exchange Reactions ◽  
Surface Welding

Covalent adaptable network (CAN) polymers can rearrange their macromolecular network by bond exchange reactions (BERs), where an active unit attaches to and then replaces a unit in an existing bond and forms a new bond. When such macromolecular events occur on the interface, they can contribute to surface welding, self-healing, and recycling of thermosetting polymers. In this paper, we study the interfacial welding and failure of CANs involving both interfacial normal and shear stresses. To do this, we incorporate our recently developed multiscale model for surface welding of CANs with a cohesive zone modeling approach in finite-element method (FEM) simulation. The developed FEM paradigm involves a multiscale model predicting the interfacial chain density and fracture energy, which are transferred to a cohesive zone model to establish the surface traction-separation law. The simulations show good agreement with experimental results on the modulus and strength of welded samples. They also provide understanding of the interactions between surface welding and material malleability in determining the final mechanical properties of polymer structures. The developed FEM model can be applied to study other complex welding problems, such as polymer reprocessing with nonregular particle size and shape.

A cohesive zone model for predicting the initiation of Mode II delamination in composites under cyclic loading

2020 ◽  
pp. 073168442094966
Author(s):  
Roham Rafiee ◽  
Sina Sotoudeh
Keyword(s):  
Numerical Simulation ◽  
Cyclic Loading ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Cohesive Elements ◽  
Damage Criterion ◽  
Damage Initiation ◽  
Number Of Cycles

A new approach for simulating delamination initiation under cyclic loading is proposed. This approach is based on the hysteresis cohesive zone modeling and the gradual degradation of interface properties. The initiation of delamination is predicted based on the monotonic traction–separation law of the interface. A damage criterion is proposed that depends on the bilinear traction–separation law and interlaminar stiffness is degraded by defining a damage parameter as a function of number of cycles and bilinear traction–separation law parameters. Numerical simulation is accomplished by implementing 2D finite element modeling for the case of double-notched specimen. Four-node zero-thickness interfacial cohesive elements are defined to capture the delamination behavior of midplane in the specimen. The results of numerical simulation are compared with available experimental data and a good agreement is observed. The main novelty of this research lies on assuming a cycle-by-cycle irreversible decrease in interlaminar stiffness prior to damage initiation and applying a damage criterion based on the bilinear traction–separation law in order to predict the number of cycles for initiation of delamination.

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