The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform
Jong Shin Huang - One of the best experts on this subject based on the ideXlab platform.
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fatigue of honeycombs under in plane Multiaxial Loads
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2001Co-Authors: Jong Shin HuangAbstract:Abstract Modeling for fatigue of honeycombs under in-plane Multiaxial Loads is proposed and presented here. Paris law for microcrack propagation, Basquin law for high cycle fatigue and Coffin–Manson law for low cycle fatigue are employed to describe the fatigue of solid cell walls within honeycombs, respectively. As a result, the number of cycles to failure of honeycombs can be obtained by using a cell-wall-bending model and dimensional argument analysis. It is found that the fatigue of honeycombs under in-plane Multiaxial Loads depend on cyclic stress range, pre-existing macrocrack and microcrack lengths, cell size, relative density and the fatigue parameters of solid cell wall material.
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fatigue of isotropic open cell foams under Multiaxial Loads
International Journal of Fatigue, 2001Co-Authors: Jong Shin HuangAbstract:Abstract A model for describing the fatigue of isotropic open-cell foams under Multiaxial Loads is presented. The Paris law for microcrack propagation, the Basquin law for high-cycle fatigue and the Coffin–Manson law for low-cycle fatigue are employed in calculating the number of cycles to failure for solid cell struts. The Multiaxial fatigue of foams is thus obtained using dimensional argument analysis. Results suggest that the Multiaxial fatigue of foams depends on cyclic stress ranges, relative density and the fatigue parameters of solid cell struts. Furthermore, theoretical expressions for the Multiaxial fatigue of open-cell foams can be expressed in a simple form.
Franck Morel - One of the best experts on this subject based on the ideXlab platform.
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simulation of the kitagawa takahashi diagram using a probabilistic approach for cast al si alloys under different Multiaxial Loads
International Journal of Fatigue, 2016Co-Authors: Nicolas Saintier, Franck Morel, Viet Duc Le, Daniel Bellett, Pierre OsmondAbstract:Abstract This article describes a microstructural-based high cycle fatigue strength modelling approach applied to different cast Al-Si alloys used in an automotive context. Thank to different casting processes (gravity die casting and lost foam casting), associated with several heat treatment (T7 and Hot Isostatic Pressing-HIP), three alloys with very different microstructures have been obtained. In a vast experimental campaign undertaken to investigate the fatigue damage mechanisms governing these alloys under different Multiaxial loading conditions, it was shown that the principal crack initiation mechanisms for the porosity-free alloy are either the formation of persistent slip bands (PSB) or the rupture and/or debonding of eutectic particles. For the porosity-containing alloys, the fatigue damage is always controlled by crack growth from pores. In order to take into account these fatigue damage mechanisms, a probabilistic model using a combination of the Dang Van and a modified LEFM criteria is proposed. The modified LEFM criterion is able to take into account the influence of the grain size on the threshold of the stress intensity factor. It is shown that for the porosity-free alloy, the predictions are good for combined tension-torsion Loads with R = - 1 . However, because the crack initiation mechanisms are not the same depending on the hydrostatic stress, the predictions are non-conservative for the uniaxial and equibiaxial tension Loads with R = 0.1 . For the porosity-containing alloys, the predictions are very good for the uniaxial, combined tension-torsion and equibiaxial tension Loads with both R = - 1 and R = 0.1 . As observed experimentally, the proposed model can also predict a more pronounced effect of casting porosity for the uniaxial and combined tension-torsion Loads, when compared to pure torsion Loads.
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micro mechanical modelling of high cycle fatigue behaviour of metals under Multiaxial Loads
Mechanics of Materials, 2012Co-Authors: Camille Robert, Nicolas Saintier, Thierry Palinluc, Franck MorelAbstract:Abstract An analysis of high cycle Multiaxial fatigue behaviour is conducted through the numerical simulation of polycrystalline aggregates using the finite element method. The metallic material chosen for investigation is pure copper, which has a Face Centred Cubic (FCC) crystalline microstructure. The elementary volumes are modelled in 2D using an hypothesis of generalised plane strain and consist of 300 equi-probability, randomly oriented grains with equiaxed geometry. The aggregates are loaded at levels equivalent to the average macroscopic fatigue strength at 10 7 cycles. The goal is to compute the mechanical quantities at the mesoscopic scale (i.e., average within the grain) after stabilization of the local cyclic behaviour. The results show that the mesoscopic mechanical variables are characterised by high dispersion. A statistical analysis of the response of the aggregates is undertaken for different loading modes: fully reversed tensile Loads, torsion and combined in-phase tension–torsion. Via the calculation of the local mechanical quantities for a sufficiently large number of different microstructures, a critical analysis of certain Multiaxial endurance criteria (Crossland, Dang Van and Matake) is conducted. In terms of material behaviour models, it is shown that elastic anisotropy strongly affects the scatter of the mechanical parameters used in the different criteria and that its role is predominant compared to that of crystal plasticity. The analysis of Multiaxial endurance criteria at both the macroscopic and mesoscopic scales clearly show that the critical plane type criteria (Dang Van and Matake) give an adequate estimation of the shear stress but badly reflect the scatter of the normal stress or the hydrostatic stress.
Carlos G Davila - One of the best experts on this subject based on the ideXlab platform.
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Analytical Modelling of Transverse Matrix Cracking of {±θ/90n} s Composite Laminates under Multiaxial Loading
Mechanics of Advanced Materials and Structures, 2010Co-Authors: J A Mayugo, P P Camanho, P Maimi, Carlos G DavilaAbstract:An analytical model based on the analysis of a cracked unit cell of a composite laminate subjected to Multiaxial Loads is proposed to predict the onset and accumulation of transverse matrix cracks in the 90n plies of uniformly stressed {±θ/90n} s laminates. The model predicts the effect of matrix cracks on the stiffness of the laminate, as well as the ultimate failure of the laminate, and it accounts for the effect of the ply thickness on the ply strength. Several examples describing the predictions of laminate response, from damage onset up to final failure under both uniaxial and Multiaxial Loads, are presented.
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analytical modelling of transverse matrix cracking of θ 90n s composite laminates under Multiaxial loading
Mechanics of Advanced Materials and Structures, 2010Co-Authors: J A Mayugo, P P Camanho, P Maimi, Carlos G DavilaAbstract:An analytical model based on the analysis of a cracked unit cell of a composite laminate subjected to Multiaxial Loads is proposed to predict the onset and accumulation of transverse matrix cracks in the 90n plies of uniformly stressed {±θ/90n} s laminates. The model predicts the effect of matrix cracks on the stiffness of the laminate, as well as the ultimate failure of the laminate, and it accounts for the effect of the ply thickness on the ply strength. Several examples describing the predictions of laminate response, from damage onset up to final failure under both uniaxial and Multiaxial Loads, are presented.
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Analytical Modelling of Transverse Matrix Cracking of [plus or minus Theta/90(sub n)](sub s) Composite Laminates Under Multiaxial Loading
2010Co-Authors: J A Mayugo, P P Camanho, P Maimi, Carlos G DavilaAbstract:An analytical model based on the analysis of a cracked unit cell of a composite laminate subjected to Multiaxial Loads is proposed to predict the onset and accumulation of transverse matrix cracks in the 90(sub n) plies of uniformly stressed [plus or minus Theta/90(sub n)](sub s) laminates. The model predicts the effect of matrix cracks on the stiffness of the laminate, as well as the ultimate failure of the laminate, and it accounts for the effect of the ply thickness on the ply strength. Several examples describing the predictions of laminate response, from damage onset up to final failure under both uniaxial and Multiaxial Loads, are presented.
Nicolas Saintier - One of the best experts on this subject based on the ideXlab platform.
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simulation of the kitagawa takahashi diagram using a probabilistic approach for cast al si alloys under different Multiaxial Loads
International Journal of Fatigue, 2016Co-Authors: Nicolas Saintier, Franck Morel, Viet Duc Le, Daniel Bellett, Pierre OsmondAbstract:Abstract This article describes a microstructural-based high cycle fatigue strength modelling approach applied to different cast Al-Si alloys used in an automotive context. Thank to different casting processes (gravity die casting and lost foam casting), associated with several heat treatment (T7 and Hot Isostatic Pressing-HIP), three alloys with very different microstructures have been obtained. In a vast experimental campaign undertaken to investigate the fatigue damage mechanisms governing these alloys under different Multiaxial loading conditions, it was shown that the principal crack initiation mechanisms for the porosity-free alloy are either the formation of persistent slip bands (PSB) or the rupture and/or debonding of eutectic particles. For the porosity-containing alloys, the fatigue damage is always controlled by crack growth from pores. In order to take into account these fatigue damage mechanisms, a probabilistic model using a combination of the Dang Van and a modified LEFM criteria is proposed. The modified LEFM criterion is able to take into account the influence of the grain size on the threshold of the stress intensity factor. It is shown that for the porosity-free alloy, the predictions are good for combined tension-torsion Loads with R = - 1 . However, because the crack initiation mechanisms are not the same depending on the hydrostatic stress, the predictions are non-conservative for the uniaxial and equibiaxial tension Loads with R = 0.1 . For the porosity-containing alloys, the predictions are very good for the uniaxial, combined tension-torsion and equibiaxial tension Loads with both R = - 1 and R = 0.1 . As observed experimentally, the proposed model can also predict a more pronounced effect of casting porosity for the uniaxial and combined tension-torsion Loads, when compared to pure torsion Loads.
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micro mechanical modelling of high cycle fatigue behaviour of metals under Multiaxial Loads
Mechanics of Materials, 2012Co-Authors: Camille Robert, Nicolas Saintier, Thierry Palinluc, Franck MorelAbstract:Abstract An analysis of high cycle Multiaxial fatigue behaviour is conducted through the numerical simulation of polycrystalline aggregates using the finite element method. The metallic material chosen for investigation is pure copper, which has a Face Centred Cubic (FCC) crystalline microstructure. The elementary volumes are modelled in 2D using an hypothesis of generalised plane strain and consist of 300 equi-probability, randomly oriented grains with equiaxed geometry. The aggregates are loaded at levels equivalent to the average macroscopic fatigue strength at 10 7 cycles. The goal is to compute the mechanical quantities at the mesoscopic scale (i.e., average within the grain) after stabilization of the local cyclic behaviour. The results show that the mesoscopic mechanical variables are characterised by high dispersion. A statistical analysis of the response of the aggregates is undertaken for different loading modes: fully reversed tensile Loads, torsion and combined in-phase tension–torsion. Via the calculation of the local mechanical quantities for a sufficiently large number of different microstructures, a critical analysis of certain Multiaxial endurance criteria (Crossland, Dang Van and Matake) is conducted. In terms of material behaviour models, it is shown that elastic anisotropy strongly affects the scatter of the mechanical parameters used in the different criteria and that its role is predominant compared to that of crystal plasticity. The analysis of Multiaxial endurance criteria at both the macroscopic and mesoscopic scales clearly show that the critical plane type criteria (Dang Van and Matake) give an adequate estimation of the shear stress but badly reflect the scatter of the normal stress or the hydrostatic stress.
J A Mayugo - One of the best experts on this subject based on the ideXlab platform.
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Analytical Modelling of Transverse Matrix Cracking of {±θ/90n} s Composite Laminates under Multiaxial Loading
Mechanics of Advanced Materials and Structures, 2010Co-Authors: J A Mayugo, P P Camanho, P Maimi, Carlos G DavilaAbstract:An analytical model based on the analysis of a cracked unit cell of a composite laminate subjected to Multiaxial Loads is proposed to predict the onset and accumulation of transverse matrix cracks in the 90n plies of uniformly stressed {±θ/90n} s laminates. The model predicts the effect of matrix cracks on the stiffness of the laminate, as well as the ultimate failure of the laminate, and it accounts for the effect of the ply thickness on the ply strength. Several examples describing the predictions of laminate response, from damage onset up to final failure under both uniaxial and Multiaxial Loads, are presented.
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analytical modelling of transverse matrix cracking of θ 90n s composite laminates under Multiaxial loading
Mechanics of Advanced Materials and Structures, 2010Co-Authors: J A Mayugo, P P Camanho, P Maimi, Carlos G DavilaAbstract:An analytical model based on the analysis of a cracked unit cell of a composite laminate subjected to Multiaxial Loads is proposed to predict the onset and accumulation of transverse matrix cracks in the 90n plies of uniformly stressed {±θ/90n} s laminates. The model predicts the effect of matrix cracks on the stiffness of the laminate, as well as the ultimate failure of the laminate, and it accounts for the effect of the ply thickness on the ply strength. Several examples describing the predictions of laminate response, from damage onset up to final failure under both uniaxial and Multiaxial Loads, are presented.
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Analytical Modelling of Transverse Matrix Cracking of [plus or minus Theta/90(sub n)](sub s) Composite Laminates Under Multiaxial Loading
2010Co-Authors: J A Mayugo, P P Camanho, P Maimi, Carlos G DavilaAbstract:An analytical model based on the analysis of a cracked unit cell of a composite laminate subjected to Multiaxial Loads is proposed to predict the onset and accumulation of transverse matrix cracks in the 90(sub n) plies of uniformly stressed [plus or minus Theta/90(sub n)](sub s) laminates. The model predicts the effect of matrix cracks on the stiffness of the laminate, as well as the ultimate failure of the laminate, and it accounts for the effect of the ply thickness on the ply strength. Several examples describing the predictions of laminate response, from damage onset up to final failure under both uniaxial and Multiaxial Loads, are presented.