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M F S F De Moura - One of the best experts on this subject based on the ideXlab platform.
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mode iii interlaminar fracture of carbon epoxy laminates using the six point Edge Crack torsion 6ect
Composites Part A-applied Science and Manufacturing, 2011Co-Authors: A B De Morais, A B Pereira, M F S F De MouraAbstract:The recently proposed Six-Point Edge Crack Torsion (6ECT) test was used to evaluate the mode III interlaminar fracture of carbon/epoxy laminates. Plate specimens with starter delaminations in 0/0, 0/90 and 0/45 interfaces were tested. Data reduction was performed with an effective Crack scheme validated in a previous numerical study. The tests allowed the evaluation of fairly unambiguous initiation GIIIC values and of subsequent R-curves. Examinations of specimen cross-section showed considerable lengths of pure interlaminar propagation in specimens with starter delaminations in 0/90 and 0/45 interfaces. The latter specimens had the lowest initiation GIIIC values.
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mode iii interlaminar fracture of carbon epoxy laminates using the Edge Crack torsion ect test
Composites Science and Technology, 2009Co-Authors: A B De Morais, M F S F De Moura, A B Pereira, Adriana MagalhaesAbstract:Abstract The mode III interlaminar fracture of carbon/epoxy laminates was evaluated with the Edge Crack torsion (ECT) test. Three-dimensional finite element analyses were performed in order to select two specimen geometries and an experimental data reduction scheme. Test results showed considerable non-linearity before the maximum load point and a significant R-curve effect. These features prevented an accurate definition of the initiation point. Nevertheless, analyses of non-linearity zones showed two likely initiation points corresponding to GIIIc values between 850 and 1100 J/m2 for both specimen geometries. Although any of these values is realistic, the range is too broad, thus showing the limitations of the ECT test and the need for further research.
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numerical analysis of the Edge Crack torsion test for mode iii interlaminar fracture of composite laminates
Engineering Fracture Mechanics, 2009Co-Authors: M F S F De Moura, M V Fernandez, A B De Morais, R D S G CampilhoAbstract:Abstract A detailed numerical analysis of the Edge Crack Torsion test was performed to verify its adequacy for the mode III interlaminar fracture characterization of composite laminates. A new data reduction scheme based on specimen compliance was proposed. Three-dimensional finite element analyses including a cohesive damage model were performed in order to evaluate the accuracy of perceived G IIIc values obtained with the proposed method. Despite some degree of Crack length dependency of perceived G IIIc , acceptable errors could be achieved within a certain Crack length range, which is thus recommended for experimental tests.
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Numerical analysis of the Edge Crack Torsion test for mode III interlaminar fracture of composite laminates
Elsevier, 1Co-Authors: M F S F De Moura, A B De Morais, Fernandez M.v.c., Campilho R.d.s.g.Abstract:A detailed numerical analysis of the Edge Crack Torsion test was performed to verify its adequacy for the mode III interlaminar fracture characterization of composite laminates. A new data reduction scheme based on specimen compliance was proposed. Three-dimensional finite element analyses including a cohesive damage model were performed in order to evaluate the accuracy of perceived GIIIc values obtained with the proposed method. Despite some degree of Crack length dependency of perceived GIIIc, acceptable errors could be achieved within a certain Crack length range, which is thus recommended for experimental tests.FCT - POCI/EME/57956/200
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Mode III interlaminar fracture of carbon/epoxy laminates using the Six-Point Edge Crack Torsion (6ECT)
Elsevier, 1Co-Authors: A B De Morais, Pereira A.b., M F S F De MouraAbstract:The recently proposed Six-Point Edge Crack Torsion (6ECT) test was used to evaluate the mode III interlaminar fracture of carbon/epoxy laminates. Plate specimens with starter delaminations in 0/0, 0/90 and 0/45 interfaces were tested. Data reduction was performed with an effective Crack scheme validated in a previous numerical study. The tests allowed the evaluation of fairly unambiguous initiation GIIIC values and of subsequent R-curves. Examinations of specimen cross-section showed considerable lengths of pure interlaminar propagation in specimens with starter delaminations in 0/90 and 0/45 interfaces. The latter specimens had the lowest initiation GIIIC values
Jianjun Chen - One of the best experts on this subject based on the ideXlab platform.
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application of the cohesive zone model for analysing the Edge Crack propagation of steel sheet in the cold rolling process
Fatigue & Fracture of Engineering Materials & Structures, 2017Co-Authors: Da Qian Zan, Jianjun Chen, Q Sun, Hongliang Pan, Zheng Dong WangAbstract:In the cold rolling process, the expansion and coalescence of micro-defects can make steel sheet quality descend and create Edge Crack in the steel sheet. And the Edge Crack can cause the strip rupture completely. In this research, the cohesive zone model (CZM) was used to analyse the initiation and propagation of Edge Crack in the cold rolling process with the non-reversing two-high mill. A bi-linear traction–separation law was utilized which is primarily given by the CZM parameters including the cohesive stress, T, and the cohesive energy, Γ. Compared with other popular models such as the Gurson–Tvergaard–Needleman (GTN) model, the CZM presents certain advantages because it requires a smaller number of parameters to be defined. Comparison results of the experiments and simulation illustrated that the CZM can provide accurate prediction for the propagation of Edge Crack in the cold rolling process. Parametric analysis was carried out and showed that the extent of the Crack propagation increases with the increasing of the reduction ratio.
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Study on 3D Edge Crack Extension Simulation in Cold Rolling with the Cohesive Zone Model
Applied Mechanics and Materials, 2016Co-Authors: Da Qian Zan, Jianjun Chen, Zheng Dong WangAbstract:In the cold rolling process, the Edge Crack extension can cause the strip rupture completely due to the micro manufacturing defects in the Edge. It can greatly impact on the production efficiency and cause the huge economic loss. Thus predicting the Edge Crack extension behavior becomes important to cold rolling industry. In this paper, a 3D extended finite element method (XFEM) based on the cohesive zone model (CZM) was used to study the Edge Crack extension under the non-reversing two-high mill cold rolling experiment condition. A bi-linear traction-separation law was utilized which is primarily given by the CZM parameters including the cohesive stress, T0 and the cohesive energy, Γ0. The cohesive stress was determined by hybrid technique of the thin-plate tension test and FEM simulation. The cohesive energy was obtained by the In-Situ SEM three points bending experiment. Different reductions were the mainly analysis factor which can study the extent of the Edge Crack extension by presetting the Edge notch. By comparing the experimental and simulation results, they agreed well with each other. It illustrated that the CZM can provide accurate predictions for the Edge Crack extension in the cold rolling process. Parametric analysis was carried out and showed that the extent of the Crack extension increases with the increasing of the reduction ratio.
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prediction of Edge Crack in cold rolling of silicon steel strip based on an extended gurson tvergaard needleman damage model
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2015Co-Authors: Jianjun ChenAbstract:Edge Cracking is commonly observed in cold rolling process. However, its failure mechanism is far from fully understanding due to the complex stresses and plastic flow conditions of steel strip under the rolling condition. In this paper, an extended Gurson–Tvergaard–Needleman (GTN) damage model coupled with Nahshon–Hutchinson shear damage mechanism was introduced to investigate the damage and fracture behavior of steel strip in cold rolling. The results show that extended GTN damage model is efficient in predicting the occurrence of Edge Crack in cold rolling, and the prediction is more accurate than that of the original GTN damage model. The Edge Cracking behavior under various cold rolling process parameters is investigated. It comes to the conclusion that Edge Crack extension increases with the increase of the reduction ratio, tension and the decrease of the roller radius and friction coefficient. The influence of shear damage becomes more significant in rolling condition with a larger reduction ratio, smaller roller radius, lower friction force, and tension.
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Prediction of Edge Crack in Cold Rolling of Silicon Steel Strip Based on an Extended Gurson–Tvergaard–Needleman Damage Model
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2015Co-Authors: Jianjun ChenAbstract:Edge Cracking is commonly observed in cold rolling process. However, its failure mechanism is far from fully understanding due to the complex stresses and plastic flow conditions of steel strip under the rolling condition. In this paper, an extended Gurson–Tvergaard–Needleman (GTN) damage model coupled with Nahshon–Hutchinson shear damage mechanism was introduced to investigate the damage and fracture behavior of steel strip in cold rolling. The results show that extended GTN damage model is efficient in predicting the occurrence of Edge Crack in cold rolling, and the prediction is more accurate than that of the original GTN damage model. The Edge Cracking behavior under various cold rolling process parameters is investigated. It comes to the conclusion that Edge Crack extension increases with the increase of the reduction ratio, tension and the decrease of the roller radius and friction coefficient. The influence of shear damage becomes more significant in rolling condition with a larger reduction ratio, smaller roller radius, lower friction force, and tension.
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Investigation on Validity of J-Integral of Edge Crack under Cold Rolling Condition
Applied Mechanics and Materials, 2014Co-Authors: Jianjun Chen, Xiao Xue LiAbstract:In this paper the characterization of the Edge Crack in the strip steel are studied by using numerical simulation method. The developments of the stress and strain near the Crack tip are obtained and the value of the J-integral of Edge Crack under the rolling process is then examined. FE simulation result shows that the J-integral is not always path independent in the whole rolling process. When the Crack is far away from the roller, the J-integral is path independent. When the Crack enters the cold rolling region, the unload phenomena will occur near the Crack tip which cause the incremental theory of plasticity failed and the conservation of the J-integral is not valid any more. The J-integral failure region is then determined by a series of FE simulations.
A B De Morais - One of the best experts on this subject based on the ideXlab platform.
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mode iii interlaminar fracture of carbon epoxy laminates using the six point Edge Crack torsion 6ect
Composites Part A-applied Science and Manufacturing, 2011Co-Authors: A B De Morais, A B Pereira, M F S F De MouraAbstract:The recently proposed Six-Point Edge Crack Torsion (6ECT) test was used to evaluate the mode III interlaminar fracture of carbon/epoxy laminates. Plate specimens with starter delaminations in 0/0, 0/90 and 0/45 interfaces were tested. Data reduction was performed with an effective Crack scheme validated in a previous numerical study. The tests allowed the evaluation of fairly unambiguous initiation GIIIC values and of subsequent R-curves. Examinations of specimen cross-section showed considerable lengths of pure interlaminar propagation in specimens with starter delaminations in 0/90 and 0/45 interfaces. The latter specimens had the lowest initiation GIIIC values.
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mode iii interlaminar fracture of carbon epoxy laminates using the Edge Crack torsion ect test
Composites Science and Technology, 2009Co-Authors: A B De Morais, M F S F De Moura, A B Pereira, Adriana MagalhaesAbstract:Abstract The mode III interlaminar fracture of carbon/epoxy laminates was evaluated with the Edge Crack torsion (ECT) test. Three-dimensional finite element analyses were performed in order to select two specimen geometries and an experimental data reduction scheme. Test results showed considerable non-linearity before the maximum load point and a significant R-curve effect. These features prevented an accurate definition of the initiation point. Nevertheless, analyses of non-linearity zones showed two likely initiation points corresponding to GIIIc values between 850 and 1100 J/m2 for both specimen geometries. Although any of these values is realistic, the range is too broad, thus showing the limitations of the ECT test and the need for further research.
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numerical analysis of the Edge Crack torsion test for mode iii interlaminar fracture of composite laminates
Engineering Fracture Mechanics, 2009Co-Authors: M F S F De Moura, M V Fernandez, A B De Morais, R D S G CampilhoAbstract:Abstract A detailed numerical analysis of the Edge Crack Torsion test was performed to verify its adequacy for the mode III interlaminar fracture characterization of composite laminates. A new data reduction scheme based on specimen compliance was proposed. Three-dimensional finite element analyses including a cohesive damage model were performed in order to evaluate the accuracy of perceived G IIIc values obtained with the proposed method. Despite some degree of Crack length dependency of perceived G IIIc , acceptable errors could be achieved within a certain Crack length range, which is thus recommended for experimental tests.
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Numerical analysis of the Edge Crack Torsion test for mode III interlaminar fracture of composite laminates
Elsevier, 1Co-Authors: M F S F De Moura, A B De Morais, Fernandez M.v.c., Campilho R.d.s.g.Abstract:A detailed numerical analysis of the Edge Crack Torsion test was performed to verify its adequacy for the mode III interlaminar fracture characterization of composite laminates. A new data reduction scheme based on specimen compliance was proposed. Three-dimensional finite element analyses including a cohesive damage model were performed in order to evaluate the accuracy of perceived GIIIc values obtained with the proposed method. Despite some degree of Crack length dependency of perceived GIIIc, acceptable errors could be achieved within a certain Crack length range, which is thus recommended for experimental tests.FCT - POCI/EME/57956/200
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Mode III interlaminar fracture of carbon/epoxy laminates using the Six-Point Edge Crack Torsion (6ECT)
Elsevier, 1Co-Authors: A B De Morais, Pereira A.b., M F S F De MouraAbstract:The recently proposed Six-Point Edge Crack Torsion (6ECT) test was used to evaluate the mode III interlaminar fracture of carbon/epoxy laminates. Plate specimens with starter delaminations in 0/0, 0/90 and 0/45 interfaces were tested. Data reduction was performed with an effective Crack scheme validated in a previous numerical study. The tests allowed the evaluation of fairly unambiguous initiation GIIIC values and of subsequent R-curves. Examinations of specimen cross-section showed considerable lengths of pure interlaminar propagation in specimens with starter delaminations in 0/90 and 0/45 interfaces. The latter specimens had the lowest initiation GIIIC values
W. Y. Daniel Yuen - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Microstructure Effects on Edge Crack of Thin Strip During Cold Rolling
Metallurgical and Materials Transactions B, 2011Co-Authors: Zhengyi Jiang, W. Y. Daniel YuenAbstract:Edge Cracks in cold rolling of the thin strip affect the strip quality and productivity significantly. In this study, an experimental and mechanical investigation on microstructures has been carried out to study the Edge Crack formation during cold rolling of the thin strip. The effects of the feed material microstructures on the Edge Crack evolution were studied employing optical microscopy and scanning electron microscopy (SEM). Experimental observation indicates that fine grain occurs in hot-rolled microstructure and coarse grain is produced in ferritic rolled microstructure. Different grain sizes affect significantly the formation mechanics of the microCrack, Crack initiation, and orientation of Crack extension. The grain size and grain boundaries effects on Crack retardation are discussed also during Edge Crack initiation. During the Crack growth in coarse grain, most Edge Crack tips will blunt, which improves the Crack toughness by causing less stress concentration. Overall, the fine microstructure shows a good Crack initiation resistance, whereas the coarse microstructure has a better resistance to Crack propagation. This research provides additional understanding of the mechanism of microstructure influence on Edge Crack evolution of cold strip rolling, which could be helpful for developing defect-free thin strip.
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analysis of friction and surface roughness effects on Edge Crack evolution of thin strip during cold rolling
Tribology International, 2011Co-Authors: Haibo Xie, Zhengyi Jiang, W. Y. Daniel YuenAbstract:Abstract Experimental investigation and mechanical analysis have been carried out to study the Edge Crack formation during cold strip rolling using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The effects of friction and surface roughness on Edge Crack initiation and growth rate have been discussed. Friction leads to an increase in fracture loads and decreasing the friction coefficient is effective in preventing the microCracks. Surface roughness variation along the strip width contributes to stress distribution and inhibits Crack nucleation. The findings reveal that the behaviour of Crack evolution is influenced by fracture surface roughness as well as rolling friction.
Haibo Xie - One of the best experts on this subject based on the ideXlab platform.
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analysis of friction and surface roughness effects on Edge Crack evolution of thin strip during cold rolling
Tribology International, 2011Co-Authors: Haibo Xie, Zhengyi Jiang, W. Y. Daniel YuenAbstract:Abstract Experimental investigation and mechanical analysis have been carried out to study the Edge Crack formation during cold strip rolling using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The effects of friction and surface roughness on Edge Crack initiation and growth rate have been discussed. Friction leads to an increase in fracture loads and decreasing the friction coefficient is effective in preventing the microCracks. Surface roughness variation along the strip width contributes to stress distribution and inhibits Crack nucleation. The findings reveal that the behaviour of Crack evolution is influenced by fracture surface roughness as well as rolling friction.
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Analysis of Edge Crack of thin strip during cold rolling
Materials Science Forum, 2010Co-Authors: Haibo Xie, Zhengyi Jiang, Dongbin Wei, A. Kiet TieuAbstract:Cracks in metal product significantly decrease quality and productivity of the rolled thin strip. In this paper the stress intensity factor (SIF) solution of Edge Crack defect of thin strip during cold rolling was investigated, and a globe analysis was applied to the problem of free Edge of thin strip. The effective stress intensity factor range is important because it represents the major physical cause of Crack growth. The present study provides insights of the mechanics of Edge Crack growth that has been frequently observed during thin strip rolling. The efficiency and reliability of the SIF analytical modelling has been demonstrated. The proposed method for predicting Edge Crack is useful for producing defect-free products in rolling, and provides insights of the mechanism of Edge Crack growth.
