Effective bulk properties of fiber-reinforced composites can be determined from individual constituent properties through spatial homogenization. Homogenization, in this regard, is conducted over a specifically selected volume of the material that is sufficiently small to capture complex local deformation response, while large enough to encompass all individual components, i.e. fibers and matrix. The physical dimension of such homogenization volumes is a key parameter in multiscale studies. Experimental measurement of the length scale at which the transition from micro to macroscale response occurs is challenging. In the present study, we propose a systematic approach to estimate the physical dimensions of a micro-to-macro transition length scale in terms of the number of fibers in the transverse plane of a cross-ply laminate subjected to remote tensile load. In-house fabricated cross-ply composite samples are loaded in tension in a miniature tensile frame inside a scanning electron microscope, while images are acquired from a small area of interest located on the transverse ply. Digital Image Correlation (DIC) is utilized to obtain full-field strain distribution within the area of interest at various global stress/strain intervals. Spatial averaging of strains at mesoscale is used to determine the micro-to-macro transition scale.
{"title":"Meso-Scale Strain Measurements in Fiber Reinforced Composites","authors":"B. Koohbor, C. Montgomery, S. White, N. Sottos","doi":"10.12783/ASC33/26028","DOIUrl":"https://doi.org/10.12783/ASC33/26028","url":null,"abstract":"Effective bulk properties of fiber-reinforced composites can be determined from individual constituent properties through spatial homogenization. Homogenization, in this regard, is conducted over a specifically selected volume of the material that is sufficiently small to capture complex local deformation response, while large enough to encompass all individual components, i.e. fibers and matrix. The physical dimension of such homogenization volumes is a key parameter in multiscale studies. Experimental measurement of the length scale at which the transition from micro to macroscale response occurs is challenging. In the present study, we propose a systematic approach to estimate the physical dimensions of a micro-to-macro transition length scale in terms of the number of fibers in the transverse plane of a cross-ply laminate subjected to remote tensile load. In-house fabricated cross-ply composite samples are loaded in tension in a miniature tensile frame inside a scanning electron microscope, while images are acquired from a small area of interest located on the transverse ply. Digital Image Correlation (DIC) is utilized to obtain full-field strain distribution within the area of interest at various global stress/strain intervals. Spatial averaging of strains at mesoscale is used to determine the micro-to-macro transition scale.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"77 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":"115274153","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":"On The Use of Multifunctional Z-Pins for Sensing Internal Damage in Composite Laminates Based on Electrical Resistance Measurements","authors":"R. Hart","doi":"10.12783/asc33/26120","DOIUrl":"https://doi.org/10.12783/asc33/26120","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"1 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":"116612376","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}
S. Ko, K. Chan, Reed Hawkins, Rohith Jayaram, C. Lynch, Reda El Mamoune, M. Nguyen, Nicolay Pekhotin, N. Stokes, Daniel N. Wu, M. Tuttle, Jinkyu Yang, M. Salviato
In this paper, we investigate the intra-laminar size effect of discontinuous fiber composites (DFCs) with three different unidirectional prepreg platelet sizes (75×12, 50×8, and 25×4 mm). Experimentally, we test five different sizes of single edge notched specimens, geometrically scaled (1:2/3:1/3:1/6:1/20), with the constant thickness. We observe notch insensitivity meaning that the crack initiate away from the notch, when the structure sizes are small (from the ratio 1/20 to 1/6). However, the crack always initiate for the ratio of 2/3 and 1. Bazants size effect law is used to analyze such unconventional fracturing behaviors. The experimental results are fitted using the linear regression analysis follow by the size effect law. The transition behavior of the DFCs from the strength based criteria to the energy based criteria is clearly observed. Also, as the platelet size increases, the fracture behaviors shift away from the energy based criteria, which implies a decrease in brittleness. To obtain the intra-laminar fracture energy, Gf , we have developed a finite element model based on the stochastic laminate analogy. The platelet size of 75×12 mm shows 96.8% increase in the fracture energy compared to the platelet size of 25×4 mm while behaves less brittle way. In conclusion, this study examines the effect of the platelet sizes of the DFCs in the presence of the notch. In this process, capturing the quasi-brittleness of the material using the nonlinear fracture mechanics is essential and we accomplish this using the simple size effect law. This work expands on an earlier SAMPE conference proceeding [1], and thus, there is a significant overlap in texts and figures between this and the SAMPE conference proceedings.
{"title":"Experimental and Numerical Characterization of the Intra-Laminar Fracturing Behavior in Discontinuous Fiber Composite Structures","authors":"S. Ko, K. Chan, Reed Hawkins, Rohith Jayaram, C. Lynch, Reda El Mamoune, M. Nguyen, Nicolay Pekhotin, N. Stokes, Daniel N. Wu, M. Tuttle, Jinkyu Yang, M. Salviato","doi":"10.12783/ASC33/26079","DOIUrl":"https://doi.org/10.12783/ASC33/26079","url":null,"abstract":"In this paper, we investigate the intra-laminar size effect of discontinuous fiber composites (DFCs) with three different unidirectional prepreg platelet sizes (75×12, 50×8, and 25×4 mm). Experimentally, we test five different sizes of single edge notched specimens, geometrically scaled (1:2/3:1/3:1/6:1/20), with the constant thickness. We observe notch insensitivity meaning that the crack initiate away from the notch, when the structure sizes are small (from the ratio 1/20 to 1/6). However, the crack always initiate for the ratio of 2/3 and 1. Bazants size effect law is used to analyze such unconventional fracturing behaviors. The experimental results are fitted using the linear regression analysis follow by the size effect law. The transition behavior of the DFCs from the strength based criteria to the energy based criteria is clearly observed. Also, as the platelet size increases, the fracture behaviors shift away from the energy based criteria, which implies a decrease in brittleness. To obtain the intra-laminar fracture energy, Gf , we have developed a finite element model based on the stochastic laminate analogy. The platelet size of 75×12 mm shows 96.8% increase in the fracture energy compared to the platelet size of 25×4 mm while behaves less brittle way. In conclusion, this study examines the effect of the platelet sizes of the DFCs in the presence of the notch. In this process, capturing the quasi-brittleness of the material using the nonlinear fracture mechanics is essential and we accomplish this using the simple size effect law. This work expands on an earlier SAMPE conference proceeding [1], and thus, there is a significant overlap in texts and figures between this and the SAMPE conference proceedings.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"62 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":"125059292","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}
Yosuke Nukui, Shunsuke Harashima, A. Takenaga, T. Mochizuki
The diameter of glass fiber chopped strands used for injection molding is usually from 10μm to 15μm. On the other hand, some reports have stated that the mechanical property is improved by slimming the diameter of the glass fiber chopped strands. By increasing the surface area between the glass fiber and matrix resin, in other words, an increase in the interface to bear the load is the main factor of this improvement. However, their report focused on the short-term load, so the effect on the durability strength has not been reported. This study was made to investigate the effect on the durability property by using low diameter fibers. In addition, we investigated the effect of using high strength and high modulus glass composition fibers on the durability property.
{"title":"Improvement of Durability Property by Using Low Diameter Glass Chopped Strands","authors":"Yosuke Nukui, Shunsuke Harashima, A. Takenaga, T. Mochizuki","doi":"10.12783/ASC33/25968","DOIUrl":"https://doi.org/10.12783/ASC33/25968","url":null,"abstract":"The diameter of glass fiber chopped strands used for injection molding is usually from 10μm to 15μm. On the other hand, some reports have stated that the mechanical property is improved by slimming the diameter of the glass fiber chopped strands. By increasing the surface area between the glass fiber and matrix resin, in other words, an increase in the interface to bear the load is the main factor of this improvement. However, their report focused on the short-term load, so the effect on the durability strength has not been reported. This study was made to investigate the effect on the durability property by using low diameter fibers. In addition, we investigated the effect of using high strength and high modulus glass composition fibers on the durability property.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"41 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":"131552645","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 this paper, we describe the mechanics of edge cracking and methods for determining the fracture toughness of strain locking materials using homogenized constitutive models for strain locking materials. We implemented a thermodynamically consistent constitutive model for a strain locking material into a plane stress finite element model and determined the energy release rate for a single-edge cracked configuration. Using material parameters suitable for a copper-clad polymer flexible circuit board and for a biological material, we determined the relationship between the strain energy release rate and the crack length for an applied load history using crackadvance methodology. The change of total potential energy (П = - (U-W)) as an edge crack propagates through a prismatic bar loaded in tension is determined. A polynomial is fitted to П where U is the total strain energy stored and W is the work done by the external loads for the purpose of differentiating with respect to the crack length, a. The energy release rate, G, is derived from the slope Π as a function of crack length from these numerical results. Additionally, an additively manufactured strain locking composite material specimen is produced and tensile tested. The results are used to fit the material constants to a previously derived implicit nonlinear elastic model.
{"title":"Mechanics of Edge-Cracking and Toughness Determination for Strain Locking Composite Materials","authors":"N. Payne, K. Pochiraju","doi":"10.12783/ASC33/25950","DOIUrl":"https://doi.org/10.12783/ASC33/25950","url":null,"abstract":"In this paper, we describe the mechanics of edge cracking and methods for determining the fracture toughness of strain locking materials using homogenized constitutive models for strain locking materials. We implemented a thermodynamically consistent constitutive model for a strain locking material into a plane stress finite element model and determined the energy release rate for a single-edge cracked configuration. Using material parameters suitable for a copper-clad polymer flexible circuit board and for a biological material, we determined the relationship between the strain energy release rate and the crack length for an applied load history using crackadvance methodology. The change of total potential energy (П = - (U-W)) as an edge crack propagates through a prismatic bar loaded in tension is determined. A polynomial is fitted to П where U is the total strain energy stored and W is the work done by the external loads for the purpose of differentiating with respect to the crack length, a. The energy release rate, G, is derived from the slope Π as a function of crack length from these numerical results. Additionally, an additively manufactured strain locking composite material specimen is produced and tensile tested. The results are used to fit the material constants to a previously derived implicit nonlinear elastic model.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"36 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":"132582924","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}
J. Ryan, R. Wheeler, G. Kedziora, Andrew Sharits, Samit Roy, J. Moller, I. Sizemore, D. Nepal
{"title":"MoS2 Dispersed Epoxy Composite: Influence of Solvent Quality and Surface Chemistry to Local Chemical Network Formation and its Influence on Nanoscale Toughening Mechanism","authors":"J. Ryan, R. Wheeler, G. Kedziora, Andrew Sharits, Samit Roy, J. Moller, I. Sizemore, D. Nepal","doi":"10.12783/asc33/26142","DOIUrl":"https://doi.org/10.12783/asc33/26142","url":null,"abstract":"","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"9 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":"134416178","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}
M. Pigazzini, D. Kamensky, D. Iersel, J. Remmers, Y. Bazilevs
High-fidelity progressive damage simulations of composite materials are important for advancements in damage tolerant design. We recently proposed a novel modeling approach for damage analysis of composite laminates, in which multi-layer structures are represented as individual plies connected through zero-Thickness cohesive interfaces. The model is developed in the framework of Isogeometric Analysis (IGA). By using Non-Uniform Rational B-Spline (NURBS) basis functions for representing geometries and discretizing the displacement field, IGA allows for a more direct connection between numerical simulation and CAD software. In addition, compared to traditional polynomial basis functions, NURBS functions allow for better representation of geometries and higher order inter-element continuity properties. The computational efficiency of the proposed modeling approach stems from the adoption of Kirchhoff-Love shell elements for the modeling of individual lamina. Intralaminar damage is introduced in the framework of continuum damage mechanics, in which a strain-softening damage model drives the degradation of material elastic properties. However, the use of local strain measures, in combination with strainsoftening degradation models, may lead to damage localization problems. These cause the governing equations to become ill-posed and their approximate solution to be highly mesh-sensitive. Our work aims to re-establish the objectivity with respect to the adopted discretization. We extend our analysis framework by introducing a smoothed strain field to re-place the local strain measures used in the damage model. Our approach builds on the Gradient-Enhanced Damage (GED) model and is specialized for the Kirchhoff-Love shell structural model. The smoothed strain field is obtained by solving an additional set of partial differential equations on each ply of the composite laminate. The GED model can be applied to smooth tensor-valued quantities, such as strains, on generic-shaped geometries in the three-dimensional space, including complex and curved aerospace structures modeled by means of shell elements. In this work, we propose numerical examples in order to illustrate the validity of the GED model.
{"title":"Non-Local Damage Modeling for Composite Laminates: Application to Isogeometric Analysis for Impact Simulations","authors":"M. Pigazzini, D. Kamensky, D. Iersel, J. Remmers, Y. Bazilevs","doi":"10.12783/asc33/26077","DOIUrl":"https://doi.org/10.12783/asc33/26077","url":null,"abstract":"High-fidelity progressive damage simulations of composite materials are important for advancements in damage tolerant design. We recently proposed a novel modeling approach for damage analysis of composite laminates, in which multi-layer structures are represented as individual plies connected through zero-Thickness cohesive interfaces. The model is developed in the framework of Isogeometric Analysis (IGA). By using Non-Uniform Rational B-Spline (NURBS) basis functions for representing geometries and discretizing the displacement field, IGA allows for a more direct connection between numerical simulation and CAD software. In addition, compared to traditional polynomial basis functions, NURBS functions allow for better representation of geometries and higher order inter-element continuity properties. The computational efficiency of the proposed modeling approach stems from the adoption of Kirchhoff-Love shell elements for the modeling of individual lamina. Intralaminar damage is introduced in the framework of continuum damage mechanics, in which a strain-softening damage model drives the degradation of material elastic properties. However, the use of local strain measures, in combination with strainsoftening degradation models, may lead to damage localization problems. These cause the governing equations to become ill-posed and their approximate solution to be highly mesh-sensitive. Our work aims to re-establish the objectivity with respect to the adopted discretization. We extend our analysis framework by introducing a smoothed strain field to re-place the local strain measures used in the damage model. Our approach builds on the Gradient-Enhanced Damage (GED) model and is specialized for the Kirchhoff-Love shell structural model. The smoothed strain field is obtained by solving an additional set of partial differential equations on each ply of the composite laminate. The GED model can be applied to smooth tensor-valued quantities, such as strains, on generic-shaped geometries in the three-dimensional space, including complex and curved aerospace structures modeled by means of shell elements. In this work, we propose numerical examples in order to illustrate the validity of the GED model.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"27 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":"134618459","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}
Takuya Takahashi, M. Ueda, K. Iizuka, A. Yoshimura
Kink-band failure is a representative failure mode of a unidirectional carbon fiber reinforced plastics (CFRP) under axial compressive loading. Unidirectional CFRP has initial fiber waviness, and it may trigger kink-band failure. However, initiation of kink-band is not clarified yet. In this paper, three-dimensional finite element model with an actual fiber waviness was constructed by means of X-ray computed tomography (XCT) imaging. Simulation on compression was carried out using the three-dimensional model. A small unidirectional CFRP cylinder was fabricated and scanned the internal fiber structure using an XCT system. The three-dimensional model of the unidirectional CFRP was developed from the XCT images by tracking each fiber positions along the longitudinal direction. Numerical simulation on compression was performed using the constructed three-dimensional finite element model. With increase of compressive loading, matrix deformation was increased locally at some volumes inside the unidirectional CFRP due to fiber random waviness. Matrix started to yield at the volumes, which was considered as an initiation of kink-band formation. The applied compressive load started to decrease after the matrix yielded showing snap-through behavior in the load-displacement relation. The yielded volume of the matrix expanded through the cross-section with rotation of carbon fibers, and kinkband was gradually formed. The numerical simulation revealed initiation and formation of kink-band in a unidirectional CFRP by the random fiber waviness model.
{"title":"Simulation on Kink-Band Formation Based On X-Ray Computed Tomography Modeling","authors":"Takuya Takahashi, M. Ueda, K. Iizuka, A. Yoshimura","doi":"10.12783/ASC33/26020","DOIUrl":"https://doi.org/10.12783/ASC33/26020","url":null,"abstract":"Kink-band failure is a representative failure mode of a unidirectional carbon fiber reinforced plastics (CFRP) under axial compressive loading. Unidirectional CFRP has initial fiber waviness, and it may trigger kink-band failure. However, initiation of kink-band is not clarified yet. In this paper, three-dimensional finite element model with an actual fiber waviness was constructed by means of X-ray computed tomography (XCT) imaging. Simulation on compression was carried out using the three-dimensional model. A small unidirectional CFRP cylinder was fabricated and scanned the internal fiber structure using an XCT system. The three-dimensional model of the unidirectional CFRP was developed from the XCT images by tracking each fiber positions along the longitudinal direction. Numerical simulation on compression was performed using the constructed three-dimensional finite element model. With increase of compressive loading, matrix deformation was increased locally at some volumes inside the unidirectional CFRP due to fiber random waviness. Matrix started to yield at the volumes, which was considered as an initiation of kink-band formation. The applied compressive load started to decrease after the matrix yielded showing snap-through behavior in the load-displacement relation. The yielded volume of the matrix expanded through the cross-section with rotation of carbon fibers, and kinkband was gradually formed. The numerical simulation revealed initiation and formation of kink-band in a unidirectional CFRP by the random fiber waviness model.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"38 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":"115381238","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}
Melanie Schneider, Pouria Khanbolouki, Nekoda van de Werken, Elijah Wade, R. Foudazi, M. Tehrani
Reducing graphene oxide (GO) is currently seen as one of the most cost effective and scalable methods to produce graphene sheets. This method takes exfoliated graphite in the form of graphene oxide (GO) and reduces it to reduced graphene oxide (rGO). This reduction process recovers the mechanical, thermal, and electrical properties of GO,1 making it more appealing for many applications including fillers in polymers. However, the reduction of oxygen functional groups tends to lead to lower dispersion quality and activity of rGO in polymers. This remains an issue as researchers search to produce graphene based nanocomposites for different applications. This study characterizes the thermal and mechanical properties of graphene oxide and reduced graphene oxide epoxy nanocomposites to determine the overall performance in relation to dispersion quality and nanoparticle loading. For this purpose, epoxy nanocomposites of GO (C:O ratio 1:1) and rGO (C:O ratio 5:1) with various loadings (0.5, 1.0, and 2.0 wt.%) and dispersion qualities (3 different combinations of shear mixing and horn sonication) were fabricated and characterized. Transmission optical microscopy (TOM) and scanning electron microscopy (SEM) were used to qualitatively asses the level of dispersion for each dispersion technique. Flash diffusivity analysis and differential scanning calorimetry (DSC) were employed to measure the thermal diffusivity and specific heat capacity, respectively, for each sample, from which the thermal conductivity was calculated. The thermal conductivity was then correlated to the level of dispersion and filler (GO or rGO) for the composites. Nanoindentation was utilized to assess the mechanical properties of the nanocomposites with respect to dispersion, loading, and filler type.
{"title":"Dispersion and Properties of Graphene Oxide and Reduced Graphene Oxide in Nanocomposites","authors":"Melanie Schneider, Pouria Khanbolouki, Nekoda van de Werken, Elijah Wade, R. Foudazi, M. Tehrani","doi":"10.12783/ASC33/26082","DOIUrl":"https://doi.org/10.12783/ASC33/26082","url":null,"abstract":"Reducing graphene oxide (GO) is currently seen as one of the most cost effective and scalable methods to produce graphene sheets. This method takes exfoliated graphite in the form of graphene oxide (GO) and reduces it to reduced graphene oxide (rGO). This reduction process recovers the mechanical, thermal, and electrical properties of GO,1 making it more appealing for many applications including fillers in polymers. However, the reduction of oxygen functional groups tends to lead to lower dispersion quality and activity of rGO in polymers. This remains an issue as researchers search to produce graphene based nanocomposites for different applications. This study characterizes the thermal and mechanical properties of graphene oxide and reduced graphene oxide epoxy nanocomposites to determine the overall performance in relation to dispersion quality and nanoparticle loading. For this purpose, epoxy nanocomposites of GO (C:O ratio 1:1) and rGO (C:O ratio 5:1) with various loadings (0.5, 1.0, and 2.0 wt.%) and dispersion qualities (3 different combinations of shear mixing and horn sonication) were fabricated and characterized. Transmission optical microscopy (TOM) and scanning electron microscopy (SEM) were used to qualitatively asses the level of dispersion for each dispersion technique. Flash diffusivity analysis and differential scanning calorimetry (DSC) were employed to measure the thermal diffusivity and specific heat capacity, respectively, for each sample, from which the thermal conductivity was calculated. The thermal conductivity was then correlated to the level of dispersion and filler (GO or rGO) for the composites. Nanoindentation was utilized to assess the mechanical properties of the nanocomposites with respect to dispersion, loading, and filler type.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"9 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":"114162939","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}
Over the last few decades, advances in high-performance computing, new materials characterization methods, and, more recently, an emphasis on integrated computational materials engineering (ICME) and additive manufacturing have been a catalyst for multiscale modeling and simulation-based design of materials and structures in the aerospace industry. While these advances have driven significant progress in the development of aerospace components and systems, that progress has been limited by persistent technology and infrastructure challenges that must be overcome to realize the full potential of integrated materials and systems design and simulation modeling throughout the supply chain. As a result, NASA’s Transformational Tools and Technology (TTT) Project sponsored an industry led study to define the potential 25-year future state required for integrated multiscale modeling of materials and systems (e.g., load-bearing structures) to accelerate the pace and reduce the expense of innovation in future aerospace and aeronautical systems. Herein the overall findings of this 2040 Vision study will be briefly reviewed, with an emphasis toward those applicable to ICME of composites. These findings for example include the 2040 vision state; the required interdependent core technical work areas defined as Key Elements (KE); associated critical gaps and actions to close those gaps; and major recommendations.
{"title":"NASA’s 2040 Vision Roadmap Study: A Framework for Integrated Computational Materials Engineering (ICME)","authors":"S. Arnold","doi":"10.12783/ASC33/25911","DOIUrl":"https://doi.org/10.12783/ASC33/25911","url":null,"abstract":"Over the last few decades, advances in high-performance computing, new materials characterization methods, and, more recently, an emphasis on integrated computational materials engineering (ICME) and additive manufacturing have been a catalyst for multiscale modeling and simulation-based design of materials and structures in the aerospace industry. While these advances have driven significant progress in the development of aerospace components and systems, that progress has been limited by persistent technology and infrastructure challenges that must be overcome to realize the full potential of integrated materials and systems design and simulation modeling throughout the supply chain. As a result, NASA’s Transformational Tools and Technology (TTT) Project sponsored an industry led study to define the potential 25-year future state required for integrated multiscale modeling of materials and systems (e.g., load-bearing structures) to accelerate the pace and reduce the expense of innovation in future aerospace and aeronautical systems. Herein the overall findings of this 2040 Vision study will be briefly reviewed, with an emphasis toward those applicable to ICME of composites. These findings for example include the 2040 vision state; the required interdependent core technical work areas defined as Key Elements (KE); associated critical gaps and actions to close those gaps; and major recommendations.","PeriodicalId":337735,"journal":{"name":"American Society for Composites 2018","volume":"230 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":"115106311","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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