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.
{"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}
Using self-consistent field theory (SCFT), we computed phase-separated structure of di-block copolymer to apply this structure for the matrix of a composite. For this purpose, we combined SCFT with finite element method, which enables us to consider the effect of a smoothed boundary of a carbon fiber on the phase separation. In the result, a circularly shaped carbon fiber disturbs the phase separated structure: changes from lamella phase to cylinder phase are induced by a circle fiber and this induction is emphasized with increasing the fiber radius. Furthermore, we found that four parameters, block-ratio ( f ), polymer length ( N ) and Flory-Huggins parameter ( ), volume fraction of fiber (VM) are independently important to determine the equilibrium phase structures in a matrix penetrated by a circle fiber, even if only f and N are essential in the bulk phase.
{"title":"Changes in Micro-Phase Separation of Di-Block Copolymer Melts Induced by a Circle Fiber","authors":"Y. Oya, Nao Umemoto, T. Okabe","doi":"10.12783/asc33/25966","DOIUrl":"https://doi.org/10.12783/asc33/25966","url":null,"abstract":"Using self-consistent field theory (SCFT), we computed phase-separated structure of di-block copolymer to apply this structure for the matrix of a composite. For this purpose, we combined SCFT with finite element method, which enables us to consider the effect of a smoothed boundary of a carbon fiber on the phase separation. In the result, a circularly shaped carbon fiber disturbs the phase separated structure: changes from lamella phase to cylinder phase are induced by a circle fiber and this induction is emphasized with increasing the fiber radius. Furthermore, we found that four parameters, block-ratio ( f ), polymer length ( N ) and Flory-Huggins parameter ( ), volume fraction of fiber (VM) are independently important to determine the equilibrium phase structures in a matrix penetrated by a circle fiber, even if only f and N are essential in the bulk phase.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"19 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":"132397697","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}
Petar Dotchev, Seyed Hamid Reza Sanei, E. Steinmetz, Jason J. Williams
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.
{"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}
{"title":"3D Printed Continuous Fibre Composites: Exploiting Design Flexibility to Achieve Application Specific Properties","authors":"M. Joosten, Matt Alizzi, C. Wiles, R. Varley","doi":"10.12783/ASC33/26148","DOIUrl":"https://doi.org/10.12783/ASC33/26148","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"18 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":"133579186","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}
Additive manufacturing of polymers and their composites is an area of increasing academic and industrial interest due to the ability to agilely create complex prototype structures. While efforts continue to attempt to directly print more structural composite element, an alternative approach is to use additive printing with traditional composite processing methods to enable structural multifunctional composite concepts. Within this paper we demonstrate the application of fused deposition printing of sacrificial polymer material to enable embedded microvascular channels within structural composites to enable pressure sensing of morphing structures and for installing pressure tappings for studying hypersonic fluid-structure interactions. Overall, this processing methodology enables many type of microvascular composites whose channels can be computer designed, additively printed, integrated with traditional laminate processing, and effectively evacuated to enable a variety of multifunctional concepts.
{"title":"Additive Processing of Sacrificial Polymers to Enable Pressure Sensing in Structural Composites","authors":"G. Tandon, A. Abbott, T. Gibson, J. Baur","doi":"10.12783/ASC33/26141","DOIUrl":"https://doi.org/10.12783/ASC33/26141","url":null,"abstract":"Additive manufacturing of polymers and their composites is an area of increasing academic and industrial interest due to the ability to agilely create complex prototype structures. While efforts continue to attempt to directly print more structural composite element, an alternative approach is to use additive printing with traditional composite processing methods to enable structural multifunctional composite concepts. Within this paper we demonstrate the application of fused deposition printing of sacrificial polymer material to enable embedded microvascular channels within structural composites to enable pressure sensing of morphing structures and for installing pressure tappings for studying hypersonic fluid-structure interactions. Overall, this processing methodology enables many type of microvascular composites whose channels can be computer designed, additively printed, integrated with traditional laminate processing, and effectively evacuated to enable a variety of multifunctional concepts.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"8 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":"132745937","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}
Renzhe Chen, Mingliang Jiang, Negar Kalantar, M. Moreno, A. Muliana
Medium densify fiberboard (MDF) is a composite comprising of wood fibers and epoxy resin, with a typical density range between 600-800 kg/m3. It is currently used for secondary structures in buildings such as architectural walls and facades. MDFs are typically available in flat panel forms which can be cut into various shapes for architectural design purposes. One cutting method is known as kerfing, in which a series of cuts are made on a wood panel to create flexible structures mainly through bending and twisting deformations. In this study, we present a micromechanics model of cut patterns in order to understand the overall deformations of the kerf panel. Three different cut densities, i.e., one, two, and three cuts per quarter unit-cell, of a square spiral pattern are studied. The effect of different cut densities on the uniaxial stretching of the unit-cell is examined. An experimental test is also done on a unit-cell under uniaxial stretching. The responses from the experiment and model are compared.
{"title":"Creating Flexible Structures Out of MDF Plates","authors":"Renzhe Chen, Mingliang Jiang, Negar Kalantar, M. Moreno, A. Muliana","doi":"10.12783/ASC33/26181","DOIUrl":"https://doi.org/10.12783/ASC33/26181","url":null,"abstract":"Medium densify fiberboard (MDF) is a composite comprising of wood fibers and epoxy resin, with a typical density range between 600-800 kg/m3. It is currently used for secondary structures in buildings such as architectural walls and facades. MDFs are typically available in flat panel forms which can be cut into various shapes for architectural design purposes. One cutting method is known as kerfing, in which a series of cuts are made on a wood panel to create flexible structures mainly through bending and twisting deformations. In this study, we present a micromechanics model of cut patterns in order to understand the overall deformations of the kerf panel. Three different cut densities, i.e., one, two, and three cuts per quarter unit-cell, of a square spiral pattern are studied. The effect of different cut densities on the uniaxial stretching of the unit-cell is examined. An experimental test is also done on a unit-cell under uniaxial stretching. The responses from the experiment and model are compared.","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":"127867870","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}
Lucas Kootte, C. Bisagni, Carlos G. Davila, V. Ranatunga
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.
{"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}
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%.
{"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}
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.
{"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}
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