scholarly journals Crash Analysis of Aluminum/CFRP Hybrid Adhesive Joint Parts Using Adhesive Modeling Technique Based on the Fracture Mechanics

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3364
Author(s):  
Young Cheol Kim ◽  
Soon Ho Yoon ◽  
Geunsu Joo ◽  
Hong-Kyu Jang ◽  
Ji-Hoon Kim ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Composite Laminates ◽  
Cohesive Zone Model ◽  
Failure Behavior ◽  
Zone Model ◽  
Displacement Curve ◽  
Adhesive Failure ◽  
Aluminum Composite ◽  
Explicit Finite Element ◽  
Modeling Techniques

This study describes the numerical simulation results of aluminum/carbon-fiber-reinforced plastic (CFRP) hybrid joint parts using the explicit finite-element solver LS-DYNA, with a focus on capturing the failure behavior of composite laminates as well as the adhesive capacity of the aluminum–composite interface. In this study, two types of adhesive modeling techniques were investigated: a tiebreak contact condition and a cohesive zone model. Adhesive modeling techniques have been adopted as a widely commercialized model of structural adhesives to simulate adhesive failure based on fracture mechanics. CFRP was studied with numerical simulations utilizing LS-DYNA MAT54 to analyze the crash capability of aluminum/CFRP. To evaluate the simulation model, the results were compared with the force–displacement curve from numerical analysis and experimental results. A parametric study was conducted to evaluate the effect of different fracture toughness values used by designers to predict crash capability and adhesive failure of aluminum/CFRP parts.

Numerical modeling of shear nonlinearity and failure analysis for composite laminates

2019 ◽  
Vol 233 (18) ◽  
pp. 6616-6625 ◽  
Author(s):  
Gang Wang ◽  
Purong Jia ◽  
Tao Huang
Keyword(s):  
Composite Laminates ◽  
Cohesive Zone Model ◽  
Damage Model ◽  
Tensile Specimen ◽  
Failure Behavior ◽  
Zone Model ◽  
Damage Initiation ◽  
Finite Element Software ◽  
Stiffness Reduction ◽  
Nonlinear Shear

In this paper, the shear nonlinearity and failure behavior of composite laminates were investigated with experimental and numerical method. A nonlinear shear model that includes progressive stiffness reduction and permanent shear strain was developed to characterize the nonlinear shear behavior. Strain-based failure criteria were combined with a set of stiffness degradation method to predict in-ply damage initiation and evolution of composite laminates. Delamination damage was simulated with cohesive zone model. The progressive damage model was implemented in commercial finite element software ABAQUS by a VUMAT subroutine. The capability of the proposed model was validated by predicting the tensile behavior of open-hole tensile specimen.

Fracture energy characterisation of a structured interface by means of a novel J-Integral procedure

2019 ◽  
Vol 54 (7-8) ◽  
pp. 364-378
Author(s):  
Lorenzo García-Guzmán ◽  
Luis Távara ◽  
José Reinoso ◽  
Federico París
Keyword(s):  
Finite Element ◽  
Fracture Energy ◽  
Cohesive Zone Model ◽  
Integral Formulation ◽  
Evaluation Procedure ◽  
Crack Advance ◽  
Energy Calculation ◽  
Zone Model ◽  
Displacement Curve ◽  
J Integral

In the present investigation, a J-Integral formulation for non-flat crack paths, in the framework of the cohesive zone model, is developed. The formulation allows fracture energy properties in a direction that is not necessarily coplanar with the global crack advance to be analysed. Specifically, the effective fracture energy, [Formula: see text], has been examined based on the horizontal projection of the crack advance, [Formula: see text] (also called effective crack length). The use of [Formula: see text] is convenient in several situations as the case of patterned interfaces in adhesive joints. Finite-element analysis of double cantilever beam specimens including a trapezoidal patterned interface were employed to check the accuracy of this new definition of the contour integral. Post-process of the finite-element model, including those variables involved in the fracture energy calculation, is discussed together with some considerations that distinguish the energy evaluation procedure for flat profiles from structured designs. Finally, [Formula: see text] values obtained using the modified J-Integral formulation are compared with [Formula: see text] values obtained from the load–displacement curve method for comparison purposes.

Revisiting the Problem of Debond Initiation at Fibre-Matrix Interface under Transversal Biaxial Loads - A Comparison of Several Non-Classical Fracture Mechanics Approaches

2016 ◽  
Vol 713 ◽  
pp. 232-235 ◽  
Author(s):  
L. Távara ◽  
I.G. García ◽  
Roman Vodička ◽  
C.G. Panagiotopoulos ◽  
Vladislav Mantič
Keyword(s):  
Fracture Mechanics ◽  
Cohesive Zone Model ◽  
Failure Criteria ◽  
Transverse Load ◽  
Zone Model ◽  
Interface Model ◽  
Matrix Interface ◽  
Linear Elastic ◽  
Energetic Approach ◽  
Fibre Matrix

Understanding matrix failure in LFRP composites is one of the main challenges when developing failure criteria for these materials. This work aims to study the influence of the secondary transverse load on the crack initiation at micro-scale. Four non-classical approaches of fracture mechanics are used to model the onset of fibre-matrix interface debonds: Linear Elastic Brittle Interface Model (LEBIM), an Energetic Approach for the Linear Elastic Brittle Interface Model (EA-LEBIM), an Energetic Approach for the bilinear Cohesive Zone Model (EA-CZM) and the Coupled Criterion of the Finite Fracture Mechanics (CC-FFM). Results obtained by these approaches predict that, for brittle fibre-matrix configurations, a secondary transverse compression reduces the critical value of the main transverse tension leading to the debond onset. This fact is not taken into account by the currently used failure criteria

scholarly journals Analysis on Failure Mechanism of Scarf Joints With Brittle-Ductile Adhesives Subjected to Uniaxial Tensile Loads

2013 ◽  
Author(s):  
Lijuan Liao ◽  
Toshiyuki Sawa ◽  
Chenguang Huang
Keyword(s):  
Failure Mechanism ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Adhesive Layer ◽  
Uniaxial Tensile ◽  
Zone Model ◽  
Displacement Curve ◽  
Failure Energy ◽  
Complete Failure ◽  
Scarf Joints

The failure mechanism of scarf joints with a series of angles and brittle-ductile adhesives subjected to uniaxial tensile loads is analyzed by using a numerical method which employs a cohesive zone model (CZM) with a bilinear shape in mixed-mode (mode I and II). The adopted methodology is validated via comparisons between the present simulated results and the existing experimental measurements, which illustrate that the load-bearing capacity increases as the scarf angle decreases. More important, it is observed that the failure of the joint is governed by not only the ultimate tensile loads, but also the applied tensile displacement until complete failure, which is related to the brittle-ductile properties of the adhesive layer. In addition, failure energy, which is defined by using the area of the load-displacement curve of the joint, is adopted to estimate the joint strength. Subsequently, the numerical results show that the strength of the joint adopting ductile adhesive with higher failure energy is higher than that of the joint using brittle adhesive with lower failure energy.

Numerical Modeling and Simulation of Delamination Crack Growth in CF/Epoxy Composite Laminates under Cyclic Loading Using Cohesive Zone Model

2011 ◽  
Vol 326 ◽  
pp. 37-52 ◽  
Author(s):  
Hassan Ijaz ◽  
M Aurangzeb Khan ◽  
Waqas Saleem ◽  
Sajid Raza Chaudry
Keyword(s):  
Crack Growth ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Damage Evolution ◽  
Composite Structures ◽  
Cohesive Zone Model ◽  
Fatigue Loading ◽  
Zone Model ◽  
Evolution Law ◽  
Delamination Crack

This paper presents the mathematical modelling of fatigue damage able to carry out simulation of evolution of delamination in the laminated composite structures under cyclic loadings. A new elastic fatigue damage evolution law is proposed here. A classical interface damage evolution law, which is commonly used to predict static debonding process, is modified further to incorporate fatigue delamination effects due to high cycle loadings. The proposed fatigue damage model is identified using Fracture Mechanics tests like DCB, ENF and MMB. Simulations of delamination under fatigue loading are performed and results are successfully compared with reported experimental data on HTA/6376C unidirectional material. Delamination crack growth with variable fatigue amplitude is also performed and simulation results show that the proposed fatigue damage law can also accommodate this variable amplitude phenomenon. A study of crack tip behaviour using damage variable evolution is also carried out in this paper. Finally the effect of mesh density on crack growth is also discussed.

scholarly journals On the Temperature Dependent Mechanical Response of Dynamically-loaded Shear-dominated Adhesive Structures

2021 ◽  
Vol 250 ◽  
pp. 02016
Author(s):  
Borja Erice ◽  
Maria Lißner ◽  
Jan Wittig ◽  
Andreas Hornig ◽  
Maik Gude ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Mechanical Response ◽  
Cohesive Zone Model ◽  
Split Hopkinson Pressure Bar ◽  
Adhesive Joints ◽  
Zone Model ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson Tensile Bar ◽  
Carbon Fibre Reinforced Polymer ◽  
Split Hopkinson

A mode II mechanical characterisation of the adhesive joints is performed testing shear lap joint specimens in a Split Hopkinson Tensile Bar (SHTB), equipped with a temperature chamber. The experimentallyobtained traction-separation curves were used to develop a Cohesive Zone Model (CZM) capable of representing the strain-rate and temperaturedependent mechanical response of the adhesive joints. To validate the model, End Notch Flexure (ENF) multi-material specimens made from titanium and carbon fibre reinforced polymer composite laminates were tested at different temperatures using a Split Hopkinson Pressure Bar setup with an in-house made temperature chamber. The finite element (FE) simulations of such tests employing the developed CZM showed the model’s ability to accurately predict the adhesive joints’ failure as well as to understand the failure sequence of multi-material adhesive joint combinations.

scholarly journals Size effect in particle debonding: Comparisons between finite fracture mechanics and cohesive zone model

2018 ◽  
Vol 53 (14) ◽  
pp. 1941-1954 ◽  
Author(s):  
Timothée Gentieu ◽  
Julien Jumel ◽  
Anita Catapano ◽  
James Broughton
Keyword(s):  
Fracture Mechanics ◽  
Critical Load ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Interface Strength ◽  
Particle Radius ◽  
Zone Model ◽  
Finite Fracture Mechanics ◽  
Particle Debonding ◽  
The Relationship

The present study aims at describing the debonding phenomenon of a particle embedded in an elastic matrix. Two types of fracture mechanics approaches are developed and compared in this context. The phenomenon is analytically described using a finite fracture mechanics approach, while numerical simulations are performed using a cohesive zone model to describe the decohesion process. Both methods rely on two mechanical parameters: the interface strength, σmax and the fracture energy, Gc, of the interface. Both modelling approaches produce results that show larger particles tend to debond before smaller ones although noticeable differences are observed, especially concerning the relationship between the critical load and the particle radius: in the framework of the FFM, the critical load is inversely proportional to the square root of the particle radius, while when using CZM, the critical load is inversely proportional to the particle radius.

Cohesive Zone Model and GTN Model Collation for Ductile Crack Growth

2007 ◽  
Vol 567-568 ◽  
pp. 145-148
Author(s):  
Vladislav Kozák ◽  
Ivo Dlouhý ◽  
Zdeněk Chlup
Keyword(s):  
Fracture Mechanics ◽  
Crack Propagation ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Zone Model ◽  
Interface Elements ◽  
Ductile Crack Growth ◽  
Propagation Analysis ◽  
Wide Range ◽  
Finite Element Package

The micromechanical modelling encounters a problem that is different from basic assumptions of continuum mechanics. The material is not uniform on the microscale level and the material within an element has its own complex microstructure. Therefore the concept of a representative volume element (RVE) has been introduced. The general advantage, compared to conventional fracture mechanics, is that, in principle, the parameters of the respective models depend only on the material and not on the geometry. These concepts guarantee transferability from specimen to components over a wide range of dimensions and geometries. The prediction of crack propagation through interface elements based on the fracture mechanics approach (damage) and cohesive zone model is presented. The cohesive model for crack propagation analysis is incorporated into finite element package by interface elements which separations are controlled by the traction-separation law.

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.

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