American Society for Composites 2018最新文献_第3页

Experimental Evaluation of Carbon Nanotubes for High-Stiffness Damping Augmentation in Carbon/Epoxy Composites 碳纳米管对碳/环氧复合材料高刚度阻尼增强的实验评价

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/ASC33/26036

Jeffrey J. Kim, C. Bakis, E. Smith

{"title":"Experimental Evaluation of Carbon Nanotubes for High-Stiffness Damping Augmentation in Carbon/Epoxy Composites","authors":"Jeffrey J. Kim, C. Bakis, E. Smith","doi":"10.12783/ASC33/26036","DOIUrl":"https://doi.org/10.12783/ASC33/26036","url":null,"abstract":"Carbon nanotubes (CNTs) are promising materials for increasing the damping of fiber reinforced composites on account of a hypothesized stick-slip dissipation mechanism. The current investigation aims to increase the damping of a carbon/epoxy composites by adding different types and amounts of CNTs to the interlayer regions. [90] , [0] and [0/±45] carbon/epoxy laminates were manufactured using various types and concentrations of CNTs and surfactant. Dynamic behavior was characterized in terms of the storage and loss moduli and loss factor under tensile cyclic loading. For [0] and [0/±45] laminates, the maximum increases in loss factor and loss modulus of roughly 400-600% were obtained with 10 volume percent CNT yarns aligned in the 0-deg. loading direction. The storage modulus of these laminates was not appreciably affected by the CNT yarns. Aligned CNT yarns provided higher damping than equivalent amounts of unaligned CNT buckypapers. In a series of tests on 0-deg. laminates with and without aligned CNT yarns, damping increased with strain amplitude but not with mean strain, while damping in the baseline laminate was nearly invariant with strain. This series of tests also detected no lower threshold of strain for the onset of slip by CNT and a 10x reduction in the rate of increase of damping with strain amplitude when the amplitude exceeded 190 μ.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121768126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Changes in Micro-Phase Separation of Di-Block Copolymer Melts Induced by a Circle Fiber 圆纤维诱导双嵌段共聚物熔体微相分离的变化

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/asc33/25966

Y. Oya, Nao Umemoto, T. Okabe

引用次数: 0

Nanocomposites: Manufacturing, Microstructural Characterization and Mechanical Testing 纳米复合材料:制造、微观结构表征和力学测试

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/ASC33/26060

Petar Dotchev, Seyed Hamid Reza Sanei, E. Steinmetz, Jason J. Williams

{"title":"Nanocomposites: Manufacturing, Microstructural Characterization and Mechanical Testing","authors":"Petar Dotchev, Seyed Hamid Reza Sanei, E. Steinmetz, Jason J. Williams","doi":"10.12783/ASC33/26060","DOIUrl":"https://doi.org/10.12783/ASC33/26060","url":null,"abstract":"Carbon Nanotubes (CNT) offer exceptional thermal, electrical and mechanical properties. While an increase in thermal and electrical conductivity can be readily achieved by addition of CNT to a polymer base, the subsequent effect on mechanical properties must be investigated. In this study, nanocomposite samples were manufactured using injection molding process. Multiwall Carbon Nanotube (MWCNT) masterbatch with 15 wt.% MWCNT concentrations were diluted with PA 6/6 pellets to create five different CNT concentration ranging from 3 wt.% in 3 wt.% increments. The neat polymer sample was also manufactured as a control specimen. Mechanical properties such as Young’s modulus, Tensile strength and elongations were determined to see the effect of CNT content on overall properties. Scanning Electron Microscopy (SEM) images were used to evaluate the uniform distribution of CNT in the polymer phase. The results showed that the stiffness increased as the CNT content increased, however, the increase in strength reached a threshold value around 6 wt.% beyond which the strength decreased. It was observed that the elongation decreased significantly by addition of CNT into the polymer. The elongation dropped from an average of 190% for the neat sample to 5% for 15 wt.% CNT content sample. Such decrease in elongation might render the polymer unsuitable for the application it has been designed for. The findings of this study show that improving thermal and electrical properties of polymers does not come without a sacrifice on mechanical properties.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129405047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

3D Printed Continuous Fibre Composites: Exploiting Design Flexibility to Achieve Application Specific Properties 3D打印连续纤维复合材料:开发设计灵活性，以实现特定的应用性能

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/ASC33/26148

M. Joosten, Matt Alizzi, C. Wiles, R. Varley

引用次数: 0

Additive Processing of Sacrificial Polymers to Enable Pressure Sensing in Structural Composites 牺牲聚合物的增材加工以实现结构复合材料的压力传感

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/ASC33/26141

G. Tandon, A. Abbott, T. Gibson, J. Baur

引用次数: 2

Optimization of Carbon Fiber Surfaces for Reinforcement in Advanced Polymer Composites 先进聚合物复合材料增强用碳纤维表面优化研究

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/ASC33/26105

L. Henderson, R. Varley, Filip Stojcevski, James D. Randall, Daniel J. Eyckens, B. Demir, T. Walsh

{"title":"Optimization of Carbon Fiber Surfaces for Reinforcement in Advanced Polymer Composites","authors":"L. Henderson, R. Varley, Filip Stojcevski, James D. Randall, Daniel J. Eyckens, B. Demir, T. Walsh","doi":"10.12783/ASC33/26105","DOIUrl":"https://doi.org/10.12783/ASC33/26105","url":null,"abstract":"© 2018 by DEStech Publications, Inc. All rights reserved. This paper summarizes recent efforts within our research group to optimize the interfacial adhesion of carbon fiber reinforced polymer composites (CFRPs). This effort has been approached by several avenues including surface modification of carbon fibers, and the use of molecular dynamics to determine key interfacial interactions determining optimal adhesion. Typically, surface manipulation of carbon fibers is carried out using reductive electrochemical techniques, employing irreversible single electron reduction of aryldiazonium salts. Though recent efforts have shown oxidative surface grafting of carbon fibers is possible using the Kolbe decarboxylation reaction. Both approaches create a fiber which possesses a covalently bound surface modification, able to present a myriad of chemistries to the supporting resin. Determination of interfacial shear strength (IFSS), using single filament fragmentation in epoxy resin, has shown IFSS gains of over 150%, relative to pristine unsized fiber. Interrogation of the fiber-matrix interface using molecular dynamics simulation has shown that a large degree of the IFSS gains are derived from the molecular 'drag' effect of the surface bound molecules through the polymer phase. Further benefits of this approach can also be realized by combining the surface manipulation techniques with novel sizing agents, able to plasticize the localized resin around the carbon fiber, giving a gradient interphase. When used in concert, the synergistic effects of surface modification and interphase manipulation has realized IFSS gains >250% relative to control fibers.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132754151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Creating Flexible Structures Out of MDF Plates 创建柔性结构的中密度纤维板

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/ASC33/26181

Renzhe Chen, Mingliang Jiang, Negar Kalantar, M. Moreno, A. Muliana

引用次数: 4

Study of Skin-Stringer Separation in Postbuckled Composite Aeronautical Structures 后屈曲复合材料航空结构皮弦分离研究

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/ASC33/26048

Lucas Kootte, C. Bisagni, Carlos G. Davila, V. Ranatunga

{"title":"Study of Skin-Stringer Separation in Postbuckled Composite Aeronautical Structures","authors":"Lucas Kootte, C. Bisagni, Carlos G. Davila, V. Ranatunga","doi":"10.12783/ASC33/26048","DOIUrl":"https://doi.org/10.12783/ASC33/26048","url":null,"abstract":"Aeronautical composite stiffened structures have the capability to carry loads deep into postbuckling, yet they are typically designed to operate below the buckling load to avoid potential issues with durability and structural integrity. Large out-of-plane postbuckling deformation of the skin can result in the opening of the skin-stringer interfaces, especially in the presence of defects, such as impact damage. To ensure that skin-stringer separation does not propagate in an unstable mode that can cause a complete collapse of the structure, a deeper understanding of the interaction between the postbuckling deformation and the development of damage is required. The present study represents a first step towards a methodology based on analysis and experiments to assess and improve the strength, life, and damage tolerance of stiffened composite structures subjected to postbuckling deformations. Two regions were identified in a four-stringer panel in which skin-stringer separation can occur, namely the region of maximum deflection and the region of maximum twisting. Both regions have been studied using a finite element model of a representative single-stringer specimen. For the region of maximum deflection, a seven-point bending configuration was used, in which five supports and two loading points induce buckling waves to the specimen. The region of maximum twisting was studied using an edge crack torsion configuration, with two supports and two loading points. These two configurations were studied by changing the positions of the supports and the loading points. An optimization procedure was carried out to minimize the error between the out-of-plane deformation of the representative single-stringer specimen and the corresponding region of the fourstringer panel.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"548 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134485060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Quantitative Microscopic Investigation of Mode I Fracture Surfaces of Nanosilica-Filled Epoxies 纳米二氧化硅填充环氧树脂I型断口的定量显微研究

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/ASC33/26014

Aniruddh Vashisth, T. Henry, C. Bakis

{"title":"Quantitative Microscopic Investigation of Mode I Fracture Surfaces of Nanosilica-Filled Epoxies","authors":"Aniruddh Vashisth, T. Henry, C. Bakis","doi":"10.12783/ASC33/26014","DOIUrl":"https://doi.org/10.12783/ASC33/26014","url":null,"abstract":"The addition of functionalized nanosilica (NS) particles to epoxy resins is known to improve certain mechanical properties such as modulus of elasticity and fracture toughness. In the current investigation, epoxies with and without NS reinforcement were investigated. Four NS concentrations were evaluated: 0, 15, 25 and a maximum wt% NS dependent on which of the two curing agents was used. The tensile modulus of elasticity and quasi-static Mode I fracture toughness were measured and the Mode I fracture surfaces were examined using a field emission scanning electron microscope for general imaging and a scanning laser confocal microscope for quantitative information on surface morphology. Fracture toughness, as measured by critical strain energy release rate (GIc), and fracture surface area increased monotonically with increased NS content in the epoxy cured with diethyltoluenediamine (DETDA). However, for the material cured at a higher temperature with 4-4’ diamino diphenyl sulfone (DDS), GIc and surface area reach their respective peaks at NS concentrations less than the maximum value. The primary morphological toughing mechanisms observed were particle pullout and crack deflection. The DDS cured system had higher surface area than DETDA system for any non-zero NS content, but less GIc. Analysis of the experimental results led to the conclusion that GIc of the DETDA was mostly explainable in the context of NS particle pullout, as both fracture surface area and GIc varied in rough proportion to NS content. In the DDS system, however, such proportional behavior was not observed and it is believed that competing mechanisms influence GIc at NS concentrations above 15 wt%.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"01 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127246297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Conforming Element Mesh for Realistic Textile Composite Micro-Geometry 真实感纺织复合材料微几何的一致性单元网格

American Society for Composites 2018 Pub Date : 2018-11-07 DOI: 10.12783/asc33/26102

A. Mazumder, Youqi Wang, C. Yen

{"title":"Conforming Element Mesh for Realistic Textile Composite Micro-Geometry","authors":"A. Mazumder, Youqi Wang, C. Yen","doi":"10.12783/asc33/26102","DOIUrl":"https://doi.org/10.12783/asc33/26102","url":null,"abstract":"In recent years, several computer tools, e.g., DFMA, TexGen and WiseTex have been developed to derive realistic yarn-level micro-geometries for textile composites. However, due to numerical errors, the generated micro-geometries by these computer design tools have unavoidably exhibited artificial surface interferences or narrow gaps between yarns. It is therefore problematic to directly input the micro-geometry into a commercial FEM code to generate a conforming element mesh. In this paper, a procedure is developed to generate a conforming FE mesh that matches actual yarn-toyarn and yarn-to-matrix surface inside a textile composite with a complex microgeometry. It improves the accuracy of micro-mechanics analysis. The procedure divides into five steps. Initially, the unit cell domain is discretized into a uniform cuboid finite element mesh and the yarn surface is discretized into triangular plane elements. The second step consists of calculating the intersecting points between yarn surface triangle elements and mesh gridlines in the z-direction. The third step is the removal of numerical error driven artificial surface interferences or narrow gaps between yarns. If the distance between two intersection points from two adjacent yarns is smaller than a specified tolerance, the two adjacent intersecting points are merged to the mid-point. A material type, defined by yarn number, interface or matrix, is assigned to each node. In the fourth step, the initial uniform cuboid finite element mesh is modified so as to match yarn boundaries to the finite element mesh. In the final step, material types/yarn numbers are assigned to each element based on nodal material types. If an element is composed of nodes of two different material types, it is split into two or more elements. As such, a conforming FEM mesh, which matches the element boundary to the yarn-to-yarn or yarn-to-matrix interface, can be generated.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115234600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1