Assessment of debond simulation and cohesive zone length in a bonded composite joint

2015 ◽  
Vol 69 ◽  
pp. 359-368 ◽  
Author(s):  
Gang Li ◽  
Chun Li
Keyword(s):  
Cohesive Zone ◽  
Zone Length ◽  
Composite Joint ◽  
Bonded Composite

scholarly journals Investigating Some Technical Issues on Cohesive Zone Modeling of Fracture

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
John T. Wang
Keyword(s):  
Cohesive Zone ◽  
Process Zone ◽  
Cohesive Zone Modeling ◽  
Small Scale ◽  
Zone Length ◽  
Cohesive Model ◽  
Cohesive Models ◽  
Cohesive Laws ◽  
Technical Issues ◽  
Linear Softening

This study investigates some technical issues related to the use of cohesive zone models (CZMs) in modeling the fracture of materials with negligible plasticity outside the fracture process zone. These issues include: (1) why cohesive laws of different shapes can produce similar fracture predictions, (2) under what conditions CZM predictions have a high degree of agreement with linear elastic fracture mechanics (LEFM) analysis results, (3) when the shape of cohesive laws becomes important in the fracture predictions, and (4) why the opening profile along the cohesive zone length (CZL) needs to be accurately predicted. Two cohesive models were used in this study to address these technical issues. They are the linear softening cohesive model and the Dugdale perfectly plastic cohesive model. Each cohesive model uses five cohesive laws of different maximum tractions. All cohesive laws have the same cohesive work rate (CWR) defined by the area under the traction–separation curve. The effects of the maximum traction on the cohesive zone length and the critical remote applied stress are investigated for both models. The following conclusions from this study may provide some guidelines for the prediction of fracture using CZM. For a CZM to predict a fracture load similar to that obtained by an LEFM analysis, the cohesive zone length needs to be much smaller than the crack length, which reflects the small-scale yielding condition requirement for LEFM analysis to be valid. For large-scale cohesive zone cases, the predicted critical remote applied stresses depend on the shape of the cohesive models used and can significantly deviate from LEFM results. Furthermore, this study also reveals the importance of accurately predicting the cohesive zone profile for determining the critical remote applied load.

scholarly journals Cohesive zone length of metagabbro at supershear rupture velocity

2016 ◽  
Vol 20 (4) ◽  
pp. 1207-1215 ◽  
Author(s):  
Eiichi Fukuyama ◽  
Shiqing Xu ◽  
Futoshi Yamashita ◽  
Kazuo Mizoguchi
Keyword(s):  
Cohesive Zone ◽  
Rupture Velocity ◽  
Zone Length

Investigation of bolted/bonded composite joint behaviour using design of experiments

2017 ◽  
Vol 170 ◽  
pp. 192-201 ◽  
Author(s):  
Pedro Lopez-Cruz ◽  
Jeremy Laliberté ◽  
Larry Lessard
Keyword(s):  
Design Of Experiments ◽  
Composite Joint ◽  
Bonded Composite ◽  
Joint Behaviour

Experimental characterization of Mode II fatigue delamination growth onset in composite Joints

2021 ◽  
pp. 002199832110567
Author(s):  
Felipe P Garpelli ◽  
Francis M González Ramírez ◽  
Rita de Cássia M Sales ◽  
Mariano A Arbelo ◽  
Marcos Y Shiino ◽  
...  
Keyword(s):  
Failure Process ◽  
Strain Energy Release ◽  
Fatigue Loading ◽  
Mode Ii ◽  
Adhesive Failure ◽  
Cohesive Failure ◽  
Delamination Growth ◽  
Pull Out ◽  
Composite Joint ◽  
Bonded Composite

In this article, the structural behavior of co-cured composite joint (CC), co-bonded composite joint (CB), and secondary-bonded composite joint (SB) under Mode II fatigue loading was evaluated. Fatigue performance was evaluated in sub-critical strain energy release rate (SERR) associated with Mode II fatigue induced delamination growth onset. Fatigue tests were carried out using the three-point bending End Notched Flexure test setup for different energy ratios. The experimental results are presented in terms of SERR versus number of cycles, and the SERR threshold for no growth is determined (Gth). Fractographic analyses were performed in order to identify the main failure mechanisms related to each joining technology under Mode II. The results indicated an initial cohesive failure followed by an adhesive failure promoted by crack propagation at the interface between the adhesive and the composite adherend on SB and CB samples, through the coalescence of microcracks that promote the adhesive failure process, leading to fiber pull-out from the matrix and cusps formation in the fracture surface. These results explain the low performance behavior observed on SB and CB bonded techniques. It is worth mentioning that the results and behavior observed in this work are valid only for the laminates, adhesives, surface treatment, and environmental conditions tested herein.

Interfacial Debonding and Stress Field Analysis on a Single Fiber Composite Using FEM

2008 ◽  
Author(s):  
Yi Pan ◽  
Assimina A. Pelegri
Keyword(s):  
Stress Field ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Fiber Composite ◽  
Interfacial Strength ◽  
Interfacial Debonding ◽  
Field Analysis ◽  
Zone Model ◽  
Linear Elastic ◽  
Bonded Composite

Fiber debonding in a bundled fiber reinforced polymer composite is investigated by using finite element method and cohesive zone model. Fiber and matrix are modeled as isotropic and linear elastic materials. Fiber/matrix interface is represented by a cohesive zone model governed by the traction-separation law. Effects of interfacial strength on interfacial debonding and stress field in the bundled fiber composite are examined. The stress field of the debonding composite is compared to that of perfectly bonded composite.

Augmented Cohesive Elements for Efficient Delamination Analyses of Composite Laminates

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
H. Qiao ◽  
W. Q. Chen ◽  
Q. D. Yang ◽  
J. Lua
Keyword(s):  
Cohesive Zone ◽  
Composite Structures ◽  
Nonlinear Deformation ◽  
Practical Importance ◽  
Cohesive Elements ◽  
Numerical Accuracy ◽  
Cohesive Stress ◽  
Zone Length ◽  
Gaussian Integration ◽  
Stress Integration

In this paper, a new type of cohesive element that employs multiple subdomain integration (MSDI) for improved cohesive stress integration accuracy of bonded plate/shell elements has been formulated. Within each subdomain, stress integration is compatible with existing schemes such as Gaussian integration (GI), Newton–Cotes integration, or the mixed Gaussian and subdomain integration (mixed GI&SDI). The numerical accuracy, efficiency, and robustness of this element when employing three integration methods for MSD cohesive stress integration have been evaluated and compared through a benchmark mode-I fracture problem of bonded double-cantilever plates. The MSDI offers at least 50% improvement of numerical accuracy as compared to the best integration method in literature and has the best numerical robustness. This significant improvement pushes the structural mesh size restriction from limiting size of 1/3–1/5 cohesive zone length to 1.5–2 times the cohesive zone length. The formulation is very easy to be implemented into any finite element programs including commercial packages. Furthermore, this formulation enables the use of dual-mesh for delamination analyses of bonded structural shells/plates, which is of practical importance because it greatly reduces the burden of mesh generation for complicated composite structures. It has also been demonstrated that using high-order shell/plate elements can improve the numerical accuracy in general because the nonlinear deformation profile permitted by this type of elements can better describe the nonlinear deformation in the crack-tip element (partially bonded elements).

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