The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Jean-luc Rebiere - One of the best experts on this subject based on the ideXlab platform.
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the initiation of transverse matrix Cracking and Longitudinal matrix Cracking in composite cross ply laminates analysis of a damage criterion
Cogent engineering, 2016Co-Authors: Jean-luc RebiereAbstract:AbstractThe results of stress field distribution in damage cross-ply laminates prompt us to elaborate an energy criterion. This criterion is based on the partial parts’s computation of the strain energy release rate associated with each damage type and for all loading modes. In the related criterion, based on the linear fracture approach, several hypotheses are used to simplify the damage criterion. The main objective with this approach is to estimate the onset of transverse and Longitudinal Cracking mechanisms and the development of the damage. Only results from numerical simulations are proposed for one material; numerous numerical simulations, with other materials and laminate architectures, give similar evolutions of matrix Cracking damage.
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Transverse and Longitudinal matrix Cracking evolution in composite laminates a damage criterion
2015Co-Authors: Jean-luc RebiereAbstract:After numerous numerical simulation on the distribution of the stress field in damage composite cross ply laminates we have elaborate an energy criterion. This energy criterion is based on the computation of some partial parts of the strain energy release rate associated with each damage types and for the three loading mode (mode I (opening mode), mode II (sliding mode) and mode III (tearing mode)). In the related criterion, linear fracture based approach, several hypothesis are used to simplify the damage criterion. The main objective with this approach is to estimate the initiation of transverse and Longitudinal Cracking mechanisms and the development of the damage.
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Numerical Simulation on Damage Mode Evolution in Composite Laminate
International Journal of Advanced Computer Science and Applications, 2014Co-Authors: Jean-luc RebiereAbstract:The present work follows numerous numerical simulation on the stress field analysis in a cracked cross-ply laminate. These results lead us to elaborate an energy criterion. This criterion is based on the computation of the partial strain energy release rate associated with all the three damage types: transverse Cracking, Longitudinal Cracking and delamination. The related criterion, linear fracture based approach, is used to predict and describe the initiation of the different damage mechanisms. With this approach the influence of the nature of the material constituent on the damage mechanism is computed. We also give an assessment of the strain energy release rates associated with each damage mode. This criterion checked on glass-epoxy and graphite-epoxy composite materials will now be used in future research on new bio-based composite in the laboratory. Keywords—numerical simulation; damage mechanism; transverse Cracking;Longitudinal Cracking; delamination; criterion
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Material Stiffness degradation estimated by an energy criterion for composite laminates
2014Co-Authors: Jean-luc RebiereAbstract:The proposed work has been developed as a result of the stress field analysis in a cracked cross-ply laminate. All the numerical simulation gives a lot of details on of the stress field distribution in damaged composites. Thus leading us to elaborate an energy criterion. This criterion is based on the computation of the partial strain energy release rate associated with all the three damage types: delamination, transverse and Longitudinal Cracking. The related criterion, linear fracture based approach, is used to predict and describe the initiation of the different damage mechanisms. Transverse crack damage is generally the first observed damage while the second will be generally Longitudinal Cracking or delamination. Two materials constituent were studied with this approach and the damage mechanism was observed.
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a decomposition of the strain energy release rate associated with the initiation of transverse Cracking Longitudinal Cracking and delamination in cross ply laminates
Composite Structures, 2008Co-Authors: Jean-luc Rebiere, Denys GambyAbstract:An energy criterion is proposed to study the damage evolution in a composite cross-ply laminate. This criterion is based on the computation of the partial strain energy release rate associated with each damage mechanism (transverse Cracking, Longitudinal Cracking and delamination) and mode (I, II or III). Several decompositions of the complementary strain energy are put forward. Each component part of this decomposition is related to a specific damage mechanism and loading mode. The related criterion can predict and describe the initiation and propagation of the different damage mechanisms.
Jorge A Prozzi - One of the best experts on this subject based on the ideXlab platform.
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combining geogrid reinforcement and lime treatment to control dry land Longitudinal Cracking
Transportation Research Record, 2009Co-Authors: Jorge A ProzziAbstract:In Texas, dry land Longitudinal Cracking on the farm-to-market network is one of the most prevalent pavement distresses caused by the volumetric change of expansive subgrade soils. Geogrid reinforcement and lime treatment are found to be the most effective methods to control dry land cracks. To provide a safer and more conservative approach for the pavement structure over expansive subgrade, it is desirable to combine the two methods to be more effective in controlling dry land cracks. This paper describes how to appropriately integrate geogrid and lime so that both methods can contribute to the prevention of Longitudinal cracks due to the shrinkage of expansive subgrade. Finite element modeling shows that the best place to install the geogrid should be at the interface of the lime-treated layer and the untreated soil, which is close to the initiation location of shrinkage cracks. At this location, the geogrid can effectively reduce the stress concentration at the upper crack tip. A geogrid with higher stiffness provides more benefit. Lime treatment can improve the tensile strength and fracture toughness of the expansive soil, which further reduces the possibility of cracks propagating through the lime-treated layer. Therefore, the combination of geogrid reinforcement and lime treatment is efficient for the control of dry land Longitudinal Cracking. The development of multiple shrinkage cracks helps to decrease stress concentration at the crack tips when the geogrid stiffness is at a low level. If the geogrid has an extremely high stiffness, the effect of additional shrinkage cracks is not significant in the numerical simulation.
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Benefit of Lime Treatment for Controlling Longitudinal Pavement Cracking due to Expansive Subgrade
2008Co-Authors: Jorge A ProzziAbstract:Dry-land Longitudinal Cracking is one of the most prevalent pavement distresses caused by expansive clay in pavement subgrade. In the State of Texas, using lime to stabilize expansive subgrade soil is one of the most effective methods to control pavement Longitudinal Cracking due to the shrinkage of expansive subgrade. However, the use of lime treatment is mostly based on empirical engineering experience. The mechanism of lime controlling dry-land cracks has not been addressed in depth. The benefit of lime treatment needs to be quantified. This paper develops finite element models to investigate the mechanism of lime-treated layer preventing shrinkage cracks from propagating to pavement surface. The lime treatment can significantly change the properties of the natural expansive soils through the processes of modification and stabilization. Finite element modeling results show that the tensile stress developing in the lime-treated layer is less than the tensile strength of the lime-stabilized soil. Therefore, shrinkage cracks are less likely to initiate in the lime-stabilized layer. The possible location of the shrinkage crack initiation is in the untreated soil close to the bottom of the lime-treated layer. The theoretical calculation shows that, when the initial crack propagates into the lime-treated soil, the magnitude of the stress intensity factor at the upper crack tip is in the same order of the estimated fracture toughness of the lime-treated soil. The shrinkage crack is not likely to develop through the lime-treated soil with increased fracture toughness. The occurrence of multiple shrinkage cracks reduces the stress concentration at each crack tip, which further reduces the probability of shrinkage crack propagating toward the pavement surface.
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using geogrids to minimize reflective Longitudinal Cracking on pavements over shrinking subgrades
Transportation Research Record, 2007Co-Authors: Jorge A Prozzi, Rong LuoAbstract:Texas has the most extensive network of surface-treated pavements in the United States. This network has suffered from the detrimental effects of changing environmental conditions and expansive soils in the subgrade since its deployment. Longitudinal Cracking is one the most prevalent pavement distresses caused by volumetric change of the expansive subgrade. Preliminary practice showed that geogrids can be used as reinforcement to reduce the reflection of Longitudinal Cracking on the pavement over shrinking subgrades effectively. However, little is known about the mechanism leading to propagation of the Longitudinal cracks to the surface of the pavement, and accordingly, the benefit of using geogrid treatment has not been properly quantified. The stress field and constitutive models of the subgrade soil subjected to matric suction change were evaluated. Fracture mechanics theory was used to analyze the crack propagation in the pavement and the mechanism of the geogrid reinforcement. A finite element model was developed to simulate the crack in the pavement and to estimate the stress intensity factor at the crack tips. The benefit of using geogrids was quantified by comparing the stress intensity factors of the crack in the pavement with and without a geogrid. Results showed that geogrids can significantly reduce the stress intensity factor at the crack tip in the pavement; this indicates that the desiccation cracks in the subgrade are less likely to propagate through the base layer toward the pavement surface. The geogrid with higher stiffness provided marginal additional reinforcement to the pavement structure.
Denys Gamby - One of the best experts on this subject based on the ideXlab platform.
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a decomposition of the strain energy release rate associated with the initiation of transverse Cracking Longitudinal Cracking and delamination in cross ply laminates
Composite Structures, 2008Co-Authors: Jean-luc Rebiere, Denys GambyAbstract:An energy criterion is proposed to study the damage evolution in a composite cross-ply laminate. This criterion is based on the computation of the partial strain energy release rate associated with each damage mechanism (transverse Cracking, Longitudinal Cracking and delamination) and mode (I, II or III). Several decompositions of the complementary strain energy are put forward. Each component part of this decomposition is related to a specific damage mechanism and loading mode. The related criterion can predict and describe the initiation and propagation of the different damage mechanisms.
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A criterion for modelling initiation and propagation of matrix Cracking and delamination in cross-ply laminates
Composites Science and Technology, 2004Co-Authors: Jean-luc Rebiere, Denys GambyAbstract:A variational approach is used to model the behaviour of composite cross-ply laminates damaged by transverse, Longitudinal Cracking and delamination. An energetic criterion is proposed. It is based on the strain energy release rate associated with each of the three damage modes. The first part of this paper is concerned with the modelling of the transverse and Longitudinal Cracking. In the second part, a model for studying delamination damage is presented. The numerical results show that these models provide a consistent level of accuracy for a variety of thin laminate material systems and configurations, with various combinations of delaminations and matrix cracks. In this paper several numerical simulations meant to describe initiation for each damage mode are proposed. The estimation of damage modes contributions is achieved for two thin laminates in order to predict the evolution of damage mode transition.
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Analysis of damage mode transition in a cross-ply laminate under uniaxial loading
Composite Structures, 2002Co-Authors: Jean-luc Rebiere, M.-n. Maâtallah, Denys GambyAbstract:The aim of this work is to study the transition from one damage mode to another. The three damage mechanisms usually observed in [0m/90n]s long fibre cross-ply laminates with organic matrix are transverse Cracking, which appears first, Longitudinal Cracking and/or delamination. The proposed analytical model is meant to describe the development of transverse cracks and to predict the order of initiation of subsequent damage modes; it relies on the strain energy release rate associated with each damage mechanism.
Nicole Dufalla - One of the best experts on this subject based on the ideXlab platform.
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structural model for Longitudinal Cracking in bonded whitetopping with a 1 83 m 1 83 m joint spacing
Journal of Transportation Engineering Part B: Pavements, 2017Co-Authors: Julie M Vandenbossche, Nicole DufallaAbstract:AbstractLongitudinal Cracking has been identified as the predominant distress in thin bonded whitetopping with a 1.83-m (6-ft) Longitudinal joint spacing. However, the structural models in existing...
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bonded concrete overlay of asphalt mechanical empirical design procedure
International Journal of Pavement Engineering, 2017Co-Authors: Julie M Vandenbossche, Nicole Dufalla, Zichang LiAbstract:AbstractBonded concrete overlays of asphalt pavements (BCOAs) are becoming a common rehabilitation technique used for distressed hot mix asphalt (HMA) roadways. The original design procedures were based primarily on data from instrumented pavements and finite element modelling. They were governed by the assumption that the failure mechanism was a function of the overlay thickness. However, field observations have indicated that the actual failure modes are dictated by slab size. The newly developed Bonded Concrete Overlay of Asphalt Mechanistic-Empirical design procedure (BCOA-ME) presented here is valid for overlays that are between 2.5 and 6.5 in (64–154 mm), and includes five primary enhancements to the Portland Cement Association and Colorado Department of Transportation procedures that have been traditionally used: 1.) the failure mode is dictated by the joint spacing; 2.) a new structural model for Longitudinal Cracking for 6-ft × 6-ft (1.8 m × 1.8 m) concrete overlays has been developed to better p...
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Revised Design Procedure for Thin and Ultrathin Bonded Whitetopping
Transportation Research Record, 2013Co-Authors: Julie M Vandenbossche, Nicole DufallaAbstract:Development of design procedures for bonded whitetopping overlays has been based on the assumption that failure mechanisms are a function of overlay thickness; namely, thin whitetopping results in Longitudinal Cracking and ultrathin whitetopping results in corner Cracking. However, field data from whitetopping sections indicate that failure modes are dictated by slab size rather than overlay thickness. The revised procedure presented here for thin whitetopping and ultrathin whitetopping offers four primary enhancements to the Portland Cement Association and Colorado Department of Transportation procedures that traditionally have been used: (a) the failure mode is dictated by the joint spacing and not the overlay thickness, (b) the stress adjustments factors have been calibrated with an extensive data set, (c) the equivalent gradients to be used as the design input are defined according to the pavement structure and geographical location of the project and, (d) the effect of temperature change on hot-mix a...
Xu Hongzhi - One of the best experts on this subject based on the ideXlab platform.
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a study of Longitudinal Cracking and the forming technology for deep drawn austenitic stainless steel cups
Journal of Materials Processing Technology, 1992Co-Authors: Yang Yuying, Li Chunfeng, Xu HongzhiAbstract:Abstract There often appears Longitudinal Cracking in deep-drawn austenitic stainless-steel parts that is due mainly to the presence of tangential stress and to the structure of the metal. In this paper, the X-ray diffraction (XRD) method is used to test and analyse the residual tangential stress and the content of induced martensite transformation in two kinds of stainless steel under different deformation conditions. Based on the results, a compound technology of smaller clearance drawing and ironing is presented. The results of testing verify that deep stainless-steel cups with fewer stages of deformation, a lesser number of annealings and no Longitudinal Cracking can be produced through the use of this technology, which latter also can save energy and reduce pollution.
