Simulation numérique de la propagation de fissure dans les superalliages monocristallins

In this study, a numerical method is developped to simulate fatigue crack growth. This method is based on a numerical coupled analysis using a cohesive zone modelling under cyclic loading in order to develop a coupled predictive approach of the crack growth. First, we present this damage law, then its validation by a convergence study of the solution with mesh size. We apply this model to the crack growth calculations in the case of a smooth specimen with a precracking made with a single crystal superalloy. Finally, we define the method to calibrate the cohesive zone model parameters on the base of experimental tests performed in pur fatigue regime.

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Effects of asphalt concrete characteristics on cohesive zone model parameters of hot mix asphalt mixtures

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2014-0504 ◽

2016 ◽

Vol 43 (3) ◽

pp. 226-232 ◽

Cited By ~ 18

Author(s):

S. Pirmohammad ◽

H. Khoramishad ◽

M.R. Ayatollahi

Keyword(s):

Asphalt Concrete ◽

Cohesive Energy ◽

Cohesive Zone ◽

Hot Mix Asphalt ◽

Cohesive Zone Model ◽

Experimental Tests ◽

Model Parameters ◽

Zone Model ◽

Binder Type ◽

Air Void

In this paper, the effects of the main asphalt concrete characteristics including the binder type and the air void percentage on the cohesive zone model (CZM) parameters were studied. Experimental tests were conducted on semi-circular bend (SCB) specimens made of asphalt concrete and the fracture behavior was simulated using a proper CZM. The CZM parameters of various hot mix asphalt (HMA) mixtures were determined using the SCB experimental results. Five types of HMA mixtures were tested and modeled to consider the effects of binder type and air void percentage on the CZM parameters. The results showed that as the binder in HMA mixture softened, the cohesive energy strength increased, whereas enhancing the air void percentage led to reduction of the cohesive energy and strength values. Among the studied HMA mixtures, the highest values of CZM parameters were found for the HMA mixture containing a copolymer called styrene-butadiene-styrene.

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Application of a Cohesive Zone Model for Simulating Fatigue Crack Growth from Moderate to High ΔK Levels of Inconel 718

International Journal of Aerospace Engineering ◽

10.1155/2018/4048386 ◽

2018 ◽

Vol 2018 ◽

pp. 1-13

Author(s):

Huan Li ◽

Jinshan Li ◽

Huang Yuan

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Growth Rates ◽

Cohesive Zone ◽

Cohesive Zone Model ◽

Small Scale ◽

Model Parameters ◽

Zone Model ◽

Crack Growth Rates

A cyclic cohesive zone model is applied to characterize the fatigue crack growth behavior of a IN718 superalloy which is frequently used in aerospace components. In order to improve the limitation of fracture mechanics-based models, besides the predictions of the moderate fatigue crack growth rates at the Paris’ regime and the high fatigue crack growth rates at the high stress intensity factor ΔK levels, the present work is also aimed at simulating the material damage uniformly and examining the influence of the cohesive model parameters on fatigue crack growth systematically. The gradual loss of the stress-bearing ability of the material is considered through the degradation of a novel cohesive envelope. The experimental data of cracked specimens are used to validate the simulation result. Based on the reasonable estimation for the model parameters, the fatigue crack growth from moderate to high ΔK levels can be reproduced under the small-scale yielding condition, which is in fair agreement with the experimental results.

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Numerical-Experimental Correlation of Interlaminar Damage Growth in Composite Structures: Setting Cohesive Zone Model Parameters

Advances in Materials Science and Engineering ◽

10.1155/2019/2150921 ◽

2019 ◽

Vol 2019 ◽

pp. 1-16 ◽

Cited By ~ 1

Author(s):

F. Di Caprio ◽

S. Saputo ◽

A. Sellitto

Keyword(s):

Cohesive Zone ◽

Composite Laminates ◽

Composite Structures ◽

Cohesive Zone Model ◽

Numerical Models ◽

Experimental Tests ◽

Model Parameters ◽

Zone Model ◽

Growth Phenomenon ◽

Interlaminar Damage

Composite laminates are characterized by high mechanical in-plane properties while experiencing, on the contrary, a poor out-of-plane response. The composite laminates, indeed, are often highly vulnerable to interlaminar damages, also called “delaminations.” One of the main techniques used for the numerical prediction of interlaminar damage onset and growth is the cohesive zone model (CZM). However, this approach is characterised by uncertainties in the definition of the parameters needed for the implementation of the cohesive behaviour in the numerical software. To overcome this issue, in the present paper, a numerical-experimental procedure for the calibration of material parameters governing the mechanical behaviour of CZM based on cohesive surface and cohesive element approaches is presented. Indeed, by comparing the results obtained from the double cantilever beam (DCB) and end-notched flexure (ENF) experimental tests with the corresponding numerical results, it has been possible to accurately calibrate the parameters of the numerical models needed to simulate the delamination growth phenomenon at coupon level.

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