دانلود رایگان مقاله لاتین کامپوزیت پلیمری با الیاف نانولوله کربن از سایت الزویر
عنوان فارسی مقاله:
نگاشت کرنش در مقیاس میکرو در کامپوزیت های پلیمری سلسله مراتبی با الیاف نانولوله های کربنی تراز شده های پیوند خورده
عنوان انگلیسی مقاله:
Strain mapping at the micro-scale in hierarchical polymer composites with aligned carbon nanotube grafted fibers
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Digital image correlation (DIC) is a popular technique to measure deformation on the surface of a material during loading [1,2]. Theoretically, DIC can be applied at any scale provided images for analysis are available at that scale. At the macro- and meso-scale, DIC is now widely used to study deformation of different materials including fiber-reinforced composites [3e6]. When it comes to the analysis of micro-scale heterogeneity, DIC has to be combined with microscopy and it is known as micro-scale DIC (mDIC) [7e10]. In mDIC, one is confronted with many challenges including application of a small-scale random speckle pattern, imaging distortions and noise as well as stress relaxation during image acquisition in case of long capture time [9e11]. Due to these challenges, studies of fiber-reinforced composites employing mDIC are scarce. This is despite an increasing interest in realization of the microscopic phenomena taking place in these materials. The potential of mDIC to analyze deformations in composite materials at the micro-scale was assessed in Refs. [12,13]. High-resolution and low-error micro-scale strain maps could be obtained, thus further supporting the use of this technique in composites. The next-generation structural materials are envisioned to be hierarchically designed down to the nano-scale. Carbon nanomaterials like carbon nanotubes (CNTs) and graphene show promise in the development of structural composites with superior toughness and added functionality [14e17]. Their effect on deformation and damage development at the micro-scale has not yet been well understood. Reliable techniques such as mDIC are needed to promote investigations in this direction. In the present study, we explore the applicability of mDIC to the nano-engineered composites using our previously developed methodology on conventional composites [13]. The study is performed on an alumina fiber/epoxy composite with CNT grafted fi- bers (also known as “fuzzy” fibers) that is loaded under transverse 3-point bending inside an Environmental Scanning Electron Microscope (ESEM). The focus is on micro-scale features resultingfrom the presence of fibers and CNTs, and on micro-scale phenomena like debonding at the fiber/matrix interface. A high-quality random speckle pattern, optimum correlation parameters, and proper microscopy settings, which are required for an accurate identification of the micro-features and micro-phenomena with mDIC, are provided. We also validate the experimentally measured deformations against numerical predictions. The validation for composites is typically done using modeling approaches, for example, Finite Element Analysis (FEA), which provides high-accuracy solutions and can be used at different scales. In the case of nano-engineered fiber-reinforced composites, the application of Finite Element (FE) modeling is rather challenging. This is due to the scale difference between nanotubes and fibers as well as geometrical complexity of CNT assemblies. Three-dimensional (3D) computational models of fiber-reinforced composites with CNTs are rare and approaches differ. In Refs. [18,19], a multiple-step modeling strategy was proposed to include reinforcements of two scales, where CNTs were modeled as straight cylinders. In Refs. [20e22], fibers and CNTs were modeled simultaneously and a large variety of CNT configurations could be reproduced, including CNTs deposited on fibers with different alignment and orientation. In the current work, we use the latter method to derive displacement and strain fields as reference solutions to check the accuracy of mDIC measurements.
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کلمات کلیدی:
Mapping local microstructure and mechanical ... - RSC Publishing pubs.rsc.org/en/Content/ArticleHtml/2011/NR/c1nr10497g Oct 6, 2011 - The nanoscale CNTs are utilised alongside the microscale fibres, forming ... One of the possible routes to realise hierarchical composites is to grow .... Mapping images of CNTs and polymer were then generated based on the ... Mapping local microstructure and mechanical performance around ... www.rsc.org/chemical-sciences-repository/articles/article/dr000000001090?doi... The introduction of carbon nanotubes (CNTs) modifies bulk polymer ... the matrices of conventional microscale fibre-reinforced polymer compo... ... around carbon nanotube grafted silica fibres: Methodologies for hierarchical composites. Emerging Themes in Polymer Science https://books.google.com/books?isbn=0854048901 Anthony J. Ryan - 2001 - Science Models. Strong microstructural features are found in many materials, and polymers are no exception. ... Hierarchical. and ... parameter from molecular modelling to some more sophisticated schemes of mapping and reverse mapping of scales. Molecular Dynamics and Quantum Chemistry Studies of the Interactions ... https://books.google.com/books?isbn=1109109393 James Sherwood Smith - 2009 Due to the connectivity in polymers, the length scales of interest in ... a hierarchy according to their ability to address overlapping ranges of polymer time and length ... parameters from one level up to another and back again (reverse mapping). ... the quantum scale (few atoms with full electronic structure), to the micro scale ... Fullerenes—Advances in Research and Application: 2012 Edition https://books.google.com/books?isbn=1464990654 2012 - Technology & Engineering hierarchical. composites Fresh data on Nanotechnology are presented in the report “Mapping local microstructure and mechanical performance around carbon ... the matrices of conventional microscale fibre-reinforced polymer composites, ...
