The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Bhavani V Sankar - One of the best experts on this subject based on the ideXlab platform.
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A Novel Method for Dynamic Short-Beam Shear Testing of 3D Woven Composites
Experimental Mechanics, 2012Co-Authors: T R Walter, Ghatu Subhash, Bhavani V Sankar, M. C. SongAbstract:A new test method for performing dynamic short-Beam Shear tests using a momentum trapped Hopkinson pressure bar is proposed. Angle-interlock 3D woven composite specimens were tested under quasi-static and dynamic loading conditions to determine the effect of loading rate on damage evolution. The equilibrium condition in the composite specimen under dynamic loads was verified using finite element analysis of the experiment. A high speed camera was used to capture delamination initiation and propagation during both quasi-static and dynamic experiments. Analysis of the load-deflection curves and the high speed images revealed a good correlation between the modes of damage initiation and propagation with the features in the loading response. The apparent inter-laminar Shear strength and the bending stiffness increased with rate of loading. While the damage was observed to propagate at a relative steady rate during quasi-static loading, the high rate of energy input during dynamic loading resulted in a rapid propagation of damage and a subsequent loss of stiffness in the composite as noted in the load-deflection curve.
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monotonic and cyclic short Beam Shear response of 3d woven composites
Composites Science and Technology, 2010Co-Authors: T R Walter, Ghatu Subhash, Bhavani V SankarAbstract:Monotonic, multi-step and cyclic short Beam Shear tests were conducted on 2D and 3D woven composites. The test results were used to determine the effect of z-yarns on the inter-laminar Shear strength as well as the multi-loading behavior. The presence of z-yarns was found to affect not only the inter-laminar Shear strength of the composite but also the behavior of the composite beyond the elastic limit. Microscopic examination of the damaged specimens revealed large delamination cracks in 2D woven composites while delamination cracks were hindered by z-yarns in 3D composites. This crack arrest phenomena resulted in a reduction in inter-laminar crack lengths and a higher distribution of the micro-cracks throughout the 3D composite. The multi-step and cyclic loading tests are found to be useful in the monitoring of specimen behavior during short Beam Shear testing. The induced damage was quantified in terms of the loss of strength and stiffness during each loading cycle. It was found that while the 2D composites have higher damage resistance, the 3D composites have a higher damage tolerance.
Brian L. Wardle - One of the best experts on this subject based on the ideXlab platform.
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Advanced carbon fiber composite out-of-autoclave laminate manufacture via nanostructured out-of-oven conductive curing
Composites Science and Technology, 2018Co-Authors: Jeonyoon Lee, Xinchen Ni, Frederick Daso, Dale King, Jose Sánchez Gómez, Tamara Blanco Varela, Seth S. Kessler, Xianghui Xiao, Brian L. WardleAbstract:Next-generation composite manufacturing processes are needed to overcome several limitations of conventional manufacturing processes (e.g., high energy consumption). Here we explore, via experiments and modeling, the characteristics of the newly developed out-of-oven (OoO) curing technique that cures a composite laminate via resistive heating of a carbon nanotube film. When compared to oven curing of an aerospace-grade out-of-autoclave (OoA) carbon fiber prepreg advanced composite laminate, the OoO curing reduces energy consumption by over two orders of magnitude (14 vs. 0.1 MJ). Thermophysical and mechanical tests including differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), short Beam Shear (SBS), and ex-situ and in-situ double-edge notch tension (DENT) indicate that the physical and mechanical properties of OoO-cured laminates are equivalent to those of oven-cured (baseline) laminates. In addition to energy savings, the OoO curing process has the potential to reduce part-to-part variations through improved spatiotemporal temperature control.
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Damage Modelling of Thin-Ply Nano-reinforced Composite Laminates
21st International Conference on Composite Materials (ICCM), 2017Co-Authors: Carolina Furtado, Estelle Kalfon-cohen, Roberto Frias, United States, Xinchen Ni, Pedro P. Camanho, Albertino Arteiro, Brian L. Wardle, Massachusetts AvenueAbstract:© 2017 International Committee on Composite Materials. All rights reserved. Composite laminates composed of unidirectional carbon fibre-epoxy plies nano-stitched together with vertically aligned carbon nanotube arrays (A-CNT) have been recently developed. This technology has proven to improve both interlaminar and intralaminar composite strength and toughness. The consequences of nanostitching interfaces has mainly been studied by measuring the Interlaminar Shear strength (ILSS) of nanostitched interfaces and the respective baseline configurations of the same material system using short Beam Shear tests. In this study, short Beam Shear tests of unreinforced and nanostitched samples are modelled to better understand what are the effects of this type of nano-reinforcement on the mechanics of fracture of composite materials. Intralaminar damage is simulated using a continuum damage model previously proposed in the literature [1]–[3]. Interlaminar damage was simulated using a cohesive zone model implemented in ABAQUS. It was considered that the inclusion of carbon nanotubes in the interfaces leads to an increase of mode I and mode II fracture toughnesses. Since the enhancement factor was unknown, the fracture toughness of reinforced interfaces was inversely identified by analyzing the damage propagation and load displacement curves predicted by the models. The numerical results suggest that the nanostitched interfaces are ~5% or ~10-15% tougher than unreinforced interfaces depending on the carbon fibre-epoxy material system used.
W Karunasena - One of the best experts on this subject based on the ideXlab platform.
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in plane Shear behaviour of fibre composite sandwich Beams using asymmetrical Beam Shear test
Construction and Building Materials, 2010Co-Authors: Allan Manalo, Thiru Aravinthan, W KarunasenaAbstract:The in-plane Shear behaviour of a new generation composite sandwich Beam made up of glass fibre skins and modified phenolic core material was investigated to determine its application as Shear loading component in a structural Beam. Iosipescu Shear test was conducted to characterise the Shear properties of the fibre composite skins and the phenolic core material. The fibre composite sandwich Beams were then tested under asymmetrical Beam Shear to determine its behaviour under in-plane Shear loading. The results show that the in-plane Shear behaviour of the composite sandwich Beam is similar to that of the skins. A theoretical prediction of the in-plane Shear strength of the composite sandwich Beam was proposed and showed a good agreement with the experimental results. Based on the results of the study, the asymmetrical Shear test is recommended as a test method for determining the Shear properties of sandwich structures with high strength core materials.
Allan Manalo - One of the best experts on this subject based on the ideXlab platform.
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Behaviour of fibre composite sandwich structures under short and asymmetrical Beam Shear tests
Composite Structures, 2013Co-Authors: Allan ManaloAbstract:Abstract The behaviour of structural fibre composite sandwich Beams made up of glass fibre composite skins and phenolic core material was investigated under three-point short Beam and asymmetrical Beam Shear tests. The effect of the Shear span-to-depth ratio (a/D) on the strength and failure behaviour of the composite sandwich Beams was examined. The results showed that with increasing a/D ratio, the failure load of the sandwich Beam is decreasing. On the contrary, the coupling effect of flexural stresses increases with increasing a/D ratio. Noticeably, the fibre composite sandwich Beams tested under asymmetrical Beam Shear exhibited higher failure load compared to Beams tested under short Beam Shear. Analysis showed that the Shear stress in the core is more dominant than flexural stress when the a/D ratio is 1 for the sandwich Beams under short Beam test and 1–3 for the sandwich Beams tested under asymmetrical Beams Shear test. The proposed prediction equation which accounts for the combined effect of Shear and flexural stresses due to the changing a/D ratio, presented a good agreement with the experimental results, showing that it can reasonably estimate the failure load of structural fibre composite sandwich Beams.
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in plane Shear behaviour of fibre composite sandwich Beams using asymmetrical Beam Shear test
Construction and Building Materials, 2010Co-Authors: Allan Manalo, Thiru Aravinthan, W KarunasenaAbstract:The in-plane Shear behaviour of a new generation composite sandwich Beam made up of glass fibre skins and modified phenolic core material was investigated to determine its application as Shear loading component in a structural Beam. Iosipescu Shear test was conducted to characterise the Shear properties of the fibre composite skins and the phenolic core material. The fibre composite sandwich Beams were then tested under asymmetrical Beam Shear to determine its behaviour under in-plane Shear loading. The results show that the in-plane Shear behaviour of the composite sandwich Beam is similar to that of the skins. A theoretical prediction of the in-plane Shear strength of the composite sandwich Beam was proposed and showed a good agreement with the experimental results. Based on the results of the study, the asymmetrical Shear test is recommended as a test method for determining the Shear properties of sandwich structures with high strength core materials.
Wen Juan Wu - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Transverse Sections of Unilateralism Carbon Fiber Reinforced Resin Matrix Composites in Shot-Beam Shear Conditions
Applied Mechanics and Materials, 2012Co-Authors: Chun Zhang, Wen Juan WuAbstract:This study investigates the transverse section property of unilateralism carbon fiber reinforced resin matrix composites in shot-Beam Shear conditions. Carbon fiber composites made in China and a composite T300 made in Japan were tested. Analysis was made for these composites on the Shear strength data and the appearance of macro characters. Possible sequence of failure initiation and propagation of each composite was proposed by the SEM with optical microscopy observations of failed specimens. The result revealed that the interfacial property is the most important factor responsible for the failure mode of unilateralism carbon fiber composites, and the Chinese carbon fiber composites need to improve the interfacial property for wider use.
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Influence of Interfacial Property on Failure Mode of Unilateralism Carbon Fiber Reinforced Resin Matrix Composite Subject to Short-Beam Shear
Advanced Materials Research, 2012Co-Authors: Wen Juan WuAbstract:This study investigates the influence of interfacial property on the failure mode and damage mechanism of carbon fiber composites subject to shot-Beam Shear. Carbon fiber CCF300 made in China and T300 made in Japan were tested under the condition of 23 degree centigrade dry. Comparison was made for these composites on the Shear strength data and the appearance of macro characters. Possible sequence of failure initiation and propagation of each composite was proposed by the SEM with optical microscopy observations of failed specimens. The result revealed that the interfacial property is the most important factor responsible for the failure mode of unilateralism carbon fiber composites, and the Chinese carbon fiber composites need to improve the interfacial property for wider use.
