The Experts below are selected from a list of 751725 Experts worldwide ranked by ideXlab platform
Litong Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of porosity on in plane and interlaminar Shear strengths of two dimensional carbon fiber reinforced silicon carbide composites
Materials & Design, 2016Co-Authors: Yi Zhang, Litong Zhang, Yongsheng Liu, Xiaowei Yin, Jiaxin ZhangAbstract:Abstract Porosity effects on Shear properties of 2D C/SiC were investigated based on the corresponding Shear damage mechanisms. The results show that as the total porosity increases from 12.2% to 26.1%, the interlaminar Shear strength decreases from 44.58 MPa to 17.80 MPa according to a power law, while the In-Plane Shear strength decreases linearly from 143.25 MPa to 74.38 MPa. Under interlaminar Shear stress, delamination is resulted from matrix cracking and interface debonding/sliding mechanisms. Effects of porosity on interlaminar Shear strength is controlled by the volume fraction of the delaminated matrix. Under In-Plane Shear stress, echelon matrix Shear cracking and large scale fiber bridging mechanisms occur. The decreasing of In-Plane Shear strength depends on the spacing between the echelon cracks. Since the interface debonding/sliding mechanism occurs under both In-Plane and interlaminar Shear stresses, a relationship is obtained that the In-Plane Shear strength equals the sum of the interlaminar Shear strength and the fiber bridging term under the minimum total porosity about 30.5%.
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oxidation effects on in plane and interlaminar Shear strengths of two dimensional carbon fiber reinforced silicon carbide composites
Carbon, 2016Co-Authors: Yi Zhang, Litong Zhang, Yongsheng Liu, Xiaoying Liu, Bo ChenAbstract:Abstract Effects of oxidation on In-Plane Shear strength and interlaminar Shear strength of two-dimensional carbon fiber reinforced silicon carbide composites (2D C/SiC) were studied based on the corresponding Shear damage mechanisms. The results showed that oxidation had resulted in severe degradations of the two strengths, however, it had little influence on the Shear failure mechanisms. Under In-Plane Shear loading, large-scale fiber bridging mechanism controlled the Shear behaviors. A modified rigid body sliding model was proposed to characterize the In-Plane Shear strength. In Comparison, interface sliding mechanism controlled the interlaminar Shear strength. Based on above failure mechanisms, the two Shear strengths were quantitatively characterized by the constituent properties, such as diameter of carbon fibers, interface sliding stress, matrix fracture energy and matrix cracking spacing. Therefore, oxidation effects on them were attributed to the decreased constituent properties which mainly results from oxidation consumption of the carbon phases. Finally, for the conditions of this study, a relationship was proposed that the interlaminar Shear strength equals the In-Plane Shear strength minus the fiber bridging stress.
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the yarn size dependence of tensile and in plane Shear properties of three dimensional needled textile reinforced ceramic matrix composites
Materials & Design, 2015Co-Authors: Huajie Xu, Litong ZhangAbstract:Abstract The yarn size scaling of tensile and In-Plane Shear properties is examined for three-dimensional needled textile reinforced ceramic matrix composites (3DN CMC) fabricated by chemical vapor infiltration. The results showed that large yarn size would cause the nonwoven yarn of 3DN CMC crimp and lower composite density, resulting in decrease of tensile and In-Plane Shear properties. The “modified lamina modeling” was presented to predict the tensile and Shear elastic moduli of 3DN CMC with different yarn size. Other two methods were also proposed to evaluate the tensile and In-Plane Shear strengths of 3DN CMC with different yarn size, respectively. All predicted results showed consistent well with the experimental results.
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the effect of z yarn density on the in plane Shear property of three dimensional stitched carbon fiber reinforced silicon carbide composites
Composites Science and Technology, 2015Co-Authors: Litong Zhang, Laifei ChengAbstract:Abstract Three types of three-dimensional stitched carbon fiber reinforced silicon carbide composites (3DS C/SiCs) were fabricated by chemical vapor infiltration with the Z-yarn density of 4, 9, and 16 stitching/cm2 (S4, S9 and S16). The results showed: 3DS C/SiCs with different Z-yarn densities had identical damage mechanism which was referred to as rigid body sliding. The fracture surfaces of both S4 and S9 lied in the stitched line plane. However, S16 exhibited the fracture morphologies of plane rise. Compared with that of S4, the In-Plane Shear strengths of S9 and S16 increased by 13.1% and 37.5%, respectively. However, the Shear moduli of them decreased by 22.2% and 36.4%. Benefitted from the studies of Turner, a formula was proposed to well predict the In-Plane Shear strength of 3DS C/SiCs with different Z-yarn density. Although they exhibited low In-Plane Shear strength, 3K 3DS C/SiCs would not alleviate the notch sensitivity through Shear stress redistribution. However, the application of them with lower Z-yarn density should be avoided. The similar conclusions as listed above may be also attained for other Z-reinforced ceramic-matrix composites because 3DS C/SiC is a representative of them.
Philippe Boisse - One of the best experts on this subject based on the ideXlab platform.
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The bias-extension test for the analysis of In-Plane Shear properties of textile composite reinforcements and prepregs: a review
International Journal of Material Forming, 2017Co-Authors: Philippe Boisse, Nahiene Hamila, E. Guzman-maldonado, A. Madeo, G. Hivet, F. Dell’isolaAbstract:The bias-extension test is a rather simple experiment aiming to determine In-Plane Shear properties of textile composite reinforcements. However the mechanics during the test involves fibrous material at large Shear strains and large rotations of the fibres. Several aspects are still being studied and are not yet modeled in a consensual manner. The standard analysis of the test is based on two assumptions: inextensibility of the fibers and rotations at the yarn crossovers without slippage. They lead to the development of zones with constant fibre orientations proper to the bias-extension test. Beyond the analysis of the test within these basic assumptions, the paper presents studies that have been carried out on the lack of verification of these hypothesis (slippage, tension in the yarns, effects of fibre bending). The effects of temperature, mesoscopic modeling and tension locking are also considered in the case of the bias-extension test.
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simulation of wrinkling during textile composite reinforcement forming influence of tensile in plane Shear and bending stiffnesses
Composites Science and Technology, 2011Co-Authors: Philippe Boisse, Nahiene Hamila, Emmanuelle Vidalsalle, Francois DumontAbstract:Wrinkling is one of the most common flaws that occur during textile composite reinforcement forming processes. These wrinkles are frequent because of the possible relative motion of fibres making up the reinforcement, leading to a very weak textile bending stiffness. It is necessary to simulate their onset but also their growth and their shape in order to verify that they do not extend to the useful part of the preform. In this paper the simulation of textile composite reinforcement forming and wrinkling is based on a simplified form of virtual internal work defined according to tensions, In-Plane Shear and bending moments on a unit woven cell. The role of the three rigidities (tensile, In-Plane Shear and bending) in wrinkling simulations is analysed. If In-Plane Shear stiffness plays a main role for onset of wrinkles in double-curved shape forming, there is no direct relation between Shear angle and wrinkling. Wrinkling is a global phenomenon depending on all strains and stiffnesses and on boundary conditions. The bending stiffness mainly determines the shape of the wrinkles and it is not possible to perform a wrinkle simulation using a membrane approach.
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computational determination of in plane Shear mechanical behaviour of textile composite reinforcements
Computational Materials Science, 2007Co-Authors: Pierre Badel, Emmanuelle Vidalsalle, Philippe BoisseAbstract:Abstract The knowledge of the mechanical behaviour of woven fabrics is necessary in many applications in particular for the simulation of textile composite forming. This mechanical behaviour is very specific due to the possible motions between the fibres and the yarns. In this paper, the In-Plane Shear behaviour is analysed from virtual tests on the Representative Unit Cell. The In-Plane Shear strains can be very large (up to 50°) in case of draping on a double curved surface. These virtual tests avoid performing tricky experimental tests. The presented 3D finite element analyses involve two main specific aspects. Firstly the boundary conditions have to render the periodicity at large deformations and, in some cases, the evolution of contacts between neighbouring yarns during the motion. Secondly the yarn that is made of thousand of fibres is modelled as a continuous medium but its constitutive law has to take its fibrous nature into account. For that reason a rate constitutive equation using a specific objective stress rate is used. It is based on the rotation of the fibre. The analysis is performed for two unit cells. Both results are in good agreement with the experiments, but the use of one of the cells turns out to be much easier.
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importance of in plane Shear rigidity in finite element analyses of woven fabric composite preforming
Composites Part A-applied Science and Manufacturing, 2006Co-Authors: Philippe Boisse, Bassem Zouari, Jeanluc DanielAbstract:A finite element made of woven unit cells under biaxial tension and In-Plane Shear is proposed for the simulation of fabric forming. The simulation is made within an explicit dynamic approach and is based on a simplified dynamic equation accounting for tension and In-Plane Shear strain energy. The biaxial tensile properties (given by two surfaces) and the In-Plane Shear properties (given by a curve) can be determined both by biaxial tensile tests and picture frame experiments or obtained by mesoscopic 3D finite element analyses of the woven unit cell. The interior load components of the proposed finite element are calculated explicitly and simply from the tensions and Shear torque on four woven cells. The results obtained by the simulations of a hemispherical forming process on a very unbalanced fabric are compared to experiments. It is shown that the tension strain energy permits to describe the asymmetry of the response but that the computation of wrinkles and of the deformed states when the locking angle is exceeded needs to take the In-Plane Shear stiffness and its evolution with Shear angle into account.
Yi Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of porosity on in plane and interlaminar Shear strengths of two dimensional carbon fiber reinforced silicon carbide composites
Materials & Design, 2016Co-Authors: Yi Zhang, Litong Zhang, Yongsheng Liu, Xiaowei Yin, Jiaxin ZhangAbstract:Abstract Porosity effects on Shear properties of 2D C/SiC were investigated based on the corresponding Shear damage mechanisms. The results show that as the total porosity increases from 12.2% to 26.1%, the interlaminar Shear strength decreases from 44.58 MPa to 17.80 MPa according to a power law, while the In-Plane Shear strength decreases linearly from 143.25 MPa to 74.38 MPa. Under interlaminar Shear stress, delamination is resulted from matrix cracking and interface debonding/sliding mechanisms. Effects of porosity on interlaminar Shear strength is controlled by the volume fraction of the delaminated matrix. Under In-Plane Shear stress, echelon matrix Shear cracking and large scale fiber bridging mechanisms occur. The decreasing of In-Plane Shear strength depends on the spacing between the echelon cracks. Since the interface debonding/sliding mechanism occurs under both In-Plane and interlaminar Shear stresses, a relationship is obtained that the In-Plane Shear strength equals the sum of the interlaminar Shear strength and the fiber bridging term under the minimum total porosity about 30.5%.
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oxidation effects on in plane and interlaminar Shear strengths of two dimensional carbon fiber reinforced silicon carbide composites
Carbon, 2016Co-Authors: Yi Zhang, Litong Zhang, Yongsheng Liu, Xiaoying Liu, Bo ChenAbstract:Abstract Effects of oxidation on In-Plane Shear strength and interlaminar Shear strength of two-dimensional carbon fiber reinforced silicon carbide composites (2D C/SiC) were studied based on the corresponding Shear damage mechanisms. The results showed that oxidation had resulted in severe degradations of the two strengths, however, it had little influence on the Shear failure mechanisms. Under In-Plane Shear loading, large-scale fiber bridging mechanism controlled the Shear behaviors. A modified rigid body sliding model was proposed to characterize the In-Plane Shear strength. In Comparison, interface sliding mechanism controlled the interlaminar Shear strength. Based on above failure mechanisms, the two Shear strengths were quantitatively characterized by the constituent properties, such as diameter of carbon fibers, interface sliding stress, matrix fracture energy and matrix cracking spacing. Therefore, oxidation effects on them were attributed to the decreased constituent properties which mainly results from oxidation consumption of the carbon phases. Finally, for the conditions of this study, a relationship was proposed that the interlaminar Shear strength equals the In-Plane Shear strength minus the fiber bridging stress.
Jiaxin Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of porosity on in plane and interlaminar Shear strengths of two dimensional carbon fiber reinforced silicon carbide composites
Materials & Design, 2016Co-Authors: Yi Zhang, Litong Zhang, Yongsheng Liu, Xiaowei Yin, Jiaxin ZhangAbstract:Abstract Porosity effects on Shear properties of 2D C/SiC were investigated based on the corresponding Shear damage mechanisms. The results show that as the total porosity increases from 12.2% to 26.1%, the interlaminar Shear strength decreases from 44.58 MPa to 17.80 MPa according to a power law, while the In-Plane Shear strength decreases linearly from 143.25 MPa to 74.38 MPa. Under interlaminar Shear stress, delamination is resulted from matrix cracking and interface debonding/sliding mechanisms. Effects of porosity on interlaminar Shear strength is controlled by the volume fraction of the delaminated matrix. Under In-Plane Shear stress, echelon matrix Shear cracking and large scale fiber bridging mechanisms occur. The decreasing of In-Plane Shear strength depends on the spacing between the echelon cracks. Since the interface debonding/sliding mechanism occurs under both In-Plane and interlaminar Shear stresses, a relationship is obtained that the In-Plane Shear strength equals the sum of the interlaminar Shear strength and the fiber bridging term under the minimum total porosity about 30.5%.
Jason Ingham - One of the best experts on this subject based on the ideXlab platform.
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design expression for the in plane Shear strength of reinforced concrete masonry
Journal of Structural Engineering-asce, 2007Co-Authors: Kok Voon, Jason InghamAbstract:Aspects relating to codification of the In-Plane Shear strength of concrete masonry walls when subjected to seismic loading are presented in this paper. Particular emphasis is placed on a model that is capable of representing the interaction between flexural ductility and masonry Shear strength to account for the reduction in Shear strength as ductility level increases. The simple method proposed here allows the strength enhancement provided by axial compression load to be separated from the masonry component of Shear strength and is considered to result from strut action. In addition, minor modifications are made to facilitate adoption of the method in the updated version of the New Zealand masonry design standard, NZS 4230:2004. Prediction of Shear strength from NZS 4230:2004 and alternative methods are compared with results from a wide range of masonry walls tests failing in Shear. It was established that the Shear equation in the former version of the New Zealand masonry standard (NZS 4230:1990) was overly conservative in its prediction of masonry Shear strength. The current National Earthquake Hazards Reduction Program (NEHRP) Shear expression was found to be commendable, but it does not address masonry Shear strength within plastic hinge regions, therefore limiting its use when designing masonry structures in seismic regions. Finally, the new Shear equation implemented in NZS 4230:2004 was found to provide significantly improved Shear strength prediction with respect to its predecessor, with accuracy close to that resulted from NEHRP.
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experimental in plane Shear strength investigation of reinforced concrete masonry walls
Journal of Structural Engineering-asce, 2006Co-Authors: Kok Voon, Jason InghamAbstract:This paper presents test results of ten single-story reinforced concrete masonry Shear walls. Test results are summarized and compared with design formulae specified by the New Zealand masonry design standard NZS 4230:1990 and by the National Earthquake Hazards Reduction Program. It was determined that the test walls exhibited Shear strength significantly exceeding the NZS 4230:1990 maximum permissible Shear stress, confirming that NZS 4230:1990 was overly conservative in accounting for masonry Shear strength. It was also confirmed from the test results that masonry Shear strength increases with the magnitude of applied axial compressive stress and the amount of Shear reinforcement, but that the Shear strength decreases inversely in relation to an increase in wall aspect ratio. In addition, it was shown that the postcracking performance of Shear dominated walls was substantially improved when uniformly distributing the Shear reinforcement up the height of the walls.
