Moira Callahan, Ruby Romsland, Kenneth J. McDonald, Brad C. McCoy
Mechanically-Fastened Fiber Reinforced Polymer Composites (MF-FRPs) are currently being used to extend the useful service life of deteriorated bridges. However, the A325 Steel fastener assemblies used to attach the MF-FRP system to the bridges are experiencing noticeable corrosion. Through electrochemical polarization measurements and Tafel analysis, the expected lifetime of the A325 fastener assembly was determined and compared to other similar materials, Military Specification Grade 5 Steel (MTD-STD) and PH 17-4 Stainless Steel (PH 17-4). ASTM B117 salt fog testing was performed on each material fastener assembly to simulate the corrosion that should be experienced by each material. The electrochemical analysis and the ASTM B117 salt fog test confirmed the MIL-STD assembly corroded at a much slower rate compared to either A325 or PH 17-4. It was determined that the useful life of the fastener assembly could be extended from 6.5 year using A325 to 372 years using MIL-STD. Implementation of this engineering materials solution will extend the useful life of the MF-FRP fastener assembly however, a cost benefit analysis determined that continuing to use A325 is still the best option given the desired useful life of the MF-FRP retrofit system is 3 to 5 years.
{"title":"Corrosion Mitigation for Mechanically-Fastened Fiber-Reinforced-Polymer Composites","authors":"Moira Callahan, Ruby Romsland, Kenneth J. McDonald, Brad C. McCoy","doi":"10.1115/imece2021-67967","DOIUrl":"https://doi.org/10.1115/imece2021-67967","url":null,"abstract":"\u0000 Mechanically-Fastened Fiber Reinforced Polymer Composites (MF-FRPs) are currently being used to extend the useful service life of deteriorated bridges. However, the A325 Steel fastener assemblies used to attach the MF-FRP system to the bridges are experiencing noticeable corrosion. Through electrochemical polarization measurements and Tafel analysis, the expected lifetime of the A325 fastener assembly was determined and compared to other similar materials, Military Specification Grade 5 Steel (MTD-STD) and PH 17-4 Stainless Steel (PH 17-4). ASTM B117 salt fog testing was performed on each material fastener assembly to simulate the corrosion that should be experienced by each material. The electrochemical analysis and the ASTM B117 salt fog test confirmed the MIL-STD assembly corroded at a much slower rate compared to either A325 or PH 17-4. It was determined that the useful life of the fastener assembly could be extended from 6.5 year using A325 to 372 years using MIL-STD. Implementation of this engineering materials solution will extend the useful life of the MF-FRP fastener assembly however, a cost benefit analysis determined that continuing to use A325 is still the best option given the desired useful life of the MF-FRP retrofit system is 3 to 5 years.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"126 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75905011","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}
Hassan K. Langat, J. K. Keraita, F. Mwema, E. T. Akinlabi
Polymer based composites are currently used in several fields including automobile, aerospace, biomedical, and domestic applications due to their high strength-to-weight ratio and other attractive properties. In the current study, silica particles are evaluated as reinforcement for three polymers namely, high impact polystyrene (HIPS), general purpose polystyrene (GPPS) and recycled low density polyethylene (rLDPE. The composites were prepared by varying the weight of silica particles in relation to the polymer matrix and then tensile, impact and thermal properties were evaluated using universal tensile testing machine, Charpy impact and differential scanning calorimeter (DSC) respectively. The mechanical results showed that for HIPS-Silica composite, the tensile strength increased with increased silica content from 13.6 MPa for pure HIPS to 13.9 MPa at 5% silica and 14.8 GPa at 31% Silica. GPPS-Silica showed slight increase in tensile strength from 16.2 MPa for pure to 33.8 MPa at 5% silica and reduced to 21.5 MPa at 31%. The rLDPE-silica composite showed reduced tensile strength from 10.4 MPa for recycled HDPE to 10.2 MPa at 5% silica and an increase at 31% silica to 11.7 MPa. The modulus of elasticity for all the samples increased with the increasing silica content. The impact strength was found to increase from 5.6 kJ/m2 for pure PS - GPPS to 8.1 kJ/m2 at 5% silica. There was no remarkable increase in impact strength at 31% silica for PS-PPS. For HIPS composite, the impact reduced from 47 kJ/m2 for pure HIPS to 37 kJ/m2 at 5% silica and 11 kJ/m2 at 31% silica. Thermal results of the composites at 31% silica were compared with pure respective polymers. In terms of thermal and mechanical properties, the general-purpose polystyrene had the highest heat absorption capacity and tensile strength. The modulus of elasticity was also reported highest in the general-purpose polystyrene composite. The results showed slight change in glass transition temperature and an increased heat absorption property when silica was added to respective polymers. Based on the results, natural silica (diatomite)-based composites may be used as green construction materials.
{"title":"Mechanical and Thermal Characterization of Silica Particle-Reinforced Polymer Composites","authors":"Hassan K. Langat, J. K. Keraita, F. Mwema, E. T. Akinlabi","doi":"10.1115/imece2021-68595","DOIUrl":"https://doi.org/10.1115/imece2021-68595","url":null,"abstract":"\u0000 Polymer based composites are currently used in several fields including automobile, aerospace, biomedical, and domestic applications due to their high strength-to-weight ratio and other attractive properties. In the current study, silica particles are evaluated as reinforcement for three polymers namely, high impact polystyrene (HIPS), general purpose polystyrene (GPPS) and recycled low density polyethylene (rLDPE. The composites were prepared by varying the weight of silica particles in relation to the polymer matrix and then tensile, impact and thermal properties were evaluated using universal tensile testing machine, Charpy impact and differential scanning calorimeter (DSC) respectively.\u0000 The mechanical results showed that for HIPS-Silica composite, the tensile strength increased with increased silica content from 13.6 MPa for pure HIPS to 13.9 MPa at 5% silica and 14.8 GPa at 31% Silica. GPPS-Silica showed slight increase in tensile strength from 16.2 MPa for pure to 33.8 MPa at 5% silica and reduced to 21.5 MPa at 31%. The rLDPE-silica composite showed reduced tensile strength from 10.4 MPa for recycled HDPE to 10.2 MPa at 5% silica and an increase at 31% silica to 11.7 MPa. The modulus of elasticity for all the samples increased with the increasing silica content. The impact strength was found to increase from 5.6 kJ/m2 for pure PS - GPPS to 8.1 kJ/m2 at 5% silica. There was no remarkable increase in impact strength at 31% silica for PS-PPS. For HIPS composite, the impact reduced from 47 kJ/m2 for pure HIPS to 37 kJ/m2 at 5% silica and 11 kJ/m2 at 31% silica.\u0000 Thermal results of the composites at 31% silica were compared with pure respective polymers. In terms of thermal and mechanical properties, the general-purpose polystyrene had the highest heat absorption capacity and tensile strength. The modulus of elasticity was also reported highest in the general-purpose polystyrene composite. The results showed slight change in glass transition temperature and an increased heat absorption property when silica was added to respective polymers. Based on the results, natural silica (diatomite)-based composites may be used as green construction materials.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74658533","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}
Micah Bibb, Margaret Nowicki, Kenneth J. McDonald, N. Zander
Many times, when 3D printed parts exceed their useful life or when there is a mistake in the manufacturing process, that 3D printed material is thrown away. To avoid such waste, that material can be shredded up and re-extruded into useable filament. There are some concerns over the degradation of the material as it is recycled and reprinted. In this study, the strength and quality of ABS plastic as it is recycled and reprinted has been investigated. The ABS at each stage of recycling was printed into “dog bone” test samples for mechanical testing. The tensile strength was measured using an MTS Universal Testing Machine. Following the completion of these tests, the chemical properties of the samples were tested using thermogravimetric analysis and differential scanning calorimetry. With each recycle, the tensile load capabilities of the ABS dropped by an average of 5.93%; however, chemical tests showed no significant degradation in thermal strength.
{"title":"Strength and Quality of Recycled Acrylonitrile Butadiene Styrene (ABS)","authors":"Micah Bibb, Margaret Nowicki, Kenneth J. McDonald, N. Zander","doi":"10.1115/imece2021-70583","DOIUrl":"https://doi.org/10.1115/imece2021-70583","url":null,"abstract":"\u0000 Many times, when 3D printed parts exceed their useful life or when there is a mistake in the manufacturing process, that 3D printed material is thrown away. To avoid such waste, that material can be shredded up and re-extruded into useable filament. There are some concerns over the degradation of the material as it is recycled and reprinted. In this study, the strength and quality of ABS plastic as it is recycled and reprinted has been investigated. The ABS at each stage of recycling was printed into “dog bone” test samples for mechanical testing. The tensile strength was measured using an MTS Universal Testing Machine. Following the completion of these tests, the chemical properties of the samples were tested using thermogravimetric analysis and differential scanning calorimetry. With each recycle, the tensile load capabilities of the ABS dropped by an average of 5.93%; however, chemical tests showed no significant degradation in thermal strength.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73620641","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. Uchayash, P. Biswas, Meah Imtiaz Zulkarnain, A. Touhami, Nazmul Islam, H. Huq
In this work, we applied Taguchi Signal-to-noise (S/N) analysis to investigate the effect of varying three process parameters, namely — sputtering power, working pressure and Ar gas flow rate on the surface, morphological and electrical properties of the RF sputtered SiO2 over Si substrate. We also inspected the contribution of a particular process parameter on these properties by applying Analysis of Variance (ANOVA). SiO2 thin films were fabricated over Si substrate using RF magnetron sputtering system. Three sets of inputs for the three mentioned process parameters were chosen; for power, we chose 100W, 150W and 200W; 5mTorr, 10mTorr and 15mTorr were chosen for pressure and three Ar gas flow rate levels at 5, 10 and 15 sccm were selected. By performing Taguchi L9 orthogonal array, nine combinations of sputtering parameters were prepared for depositing SiO2/Si Thin films. The surface morphological and electrical properties (resistivity per unit area and capacitance per unit area) of the sputtered samples were therefore inspected by analyzing the Taguchi design of experiment. Signal-to-noise (S/R) analysis presents how the properties were affected by the variation of each process parameter. ANOVA analysis showed that sputtering power and working pressure are the two dominant process parameters contributing more to surface morphological and electrical properties. A regression model for surface roughness of the SiO2/Si thin film samples was also derived. The electrical properties of the SiO2/Si thin films, however, didn’t show linear properties.
{"title":"Investigation of the Effect and Contribution of Process Parameters By Taguchi and ANOVA Analysis on the Morphological and Electrical Properties of RF Magnetron Sputtered SiO2 Over Si Substrate","authors":"S. Uchayash, P. Biswas, Meah Imtiaz Zulkarnain, A. Touhami, Nazmul Islam, H. Huq","doi":"10.1115/imece2021-73849","DOIUrl":"https://doi.org/10.1115/imece2021-73849","url":null,"abstract":"\u0000 In this work, we applied Taguchi Signal-to-noise (S/N) analysis to investigate the effect of varying three process parameters, namely — sputtering power, working pressure and Ar gas flow rate on the surface, morphological and electrical properties of the RF sputtered SiO2 over Si substrate. We also inspected the contribution of a particular process parameter on these properties by applying Analysis of Variance (ANOVA). SiO2 thin films were fabricated over Si substrate using RF magnetron sputtering system. Three sets of inputs for the three mentioned process parameters were chosen; for power, we chose 100W, 150W and 200W; 5mTorr, 10mTorr and 15mTorr were chosen for pressure and three Ar gas flow rate levels at 5, 10 and 15 sccm were selected. By performing Taguchi L9 orthogonal array, nine combinations of sputtering parameters were prepared for depositing SiO2/Si Thin films. The surface morphological and electrical properties (resistivity per unit area and capacitance per unit area) of the sputtered samples were therefore inspected by analyzing the Taguchi design of experiment. Signal-to-noise (S/R) analysis presents how the properties were affected by the variation of each process parameter. ANOVA analysis showed that sputtering power and working pressure are the two dominant process parameters contributing more to surface morphological and electrical properties. A regression model for surface roughness of the SiO2/Si thin film samples was also derived. The electrical properties of the SiO2/Si thin films, however, didn’t show linear properties.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86981352","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 a previous study by Davis and Dequenne, a Holmquist-Johnson-Cook (HJC) constitutive model for a cellular concrete with a nominal density of 1442 kg/m3 was developed from existing direct tension, uniaxial strain, and triaxial shear testing conducted at the United States Army Corps of Engineers Engineer Research and Development Center (ERDC) and Sandia National Laboratory (SNL). The resulting constitutive model was compared to depth of penetration results from testing conducted by Goodman at the Aberdeen Test Center with promising results. This study seeks to build on this previous work by producing depth of penetration and perforation experiments using non-deforming projectiles into a similar cellular concrete for validation of the fit HJC model. Depth of penetration experiments were conducted by firing into a 305 mm thick panel over a velocity range of 200–800 m/s with the strike velocity and depth of penetration recorded for each experiment. Perforation experiments were conducted over a range of 200–800 m/s against panels with thicknesses of 38 mm, 76 mm, and 114 mm with the strike velocity, residual velocity, and crater characteristics recorded for each experiment. 2D numerical simulations were conducted for each experiment and the results were compared for initial model validation, but additional experimental testing and simulation is required. There is error between the experimental and numerical results and a sensitivity analysis should be conducted to determine where additional testing is appropriate to improve the model’s correlation with experimental results.
{"title":"Holmquist-Johnson-Cook Constitutive Model Validation and Experimental Study on the Impact Response of Cellular Concrete","authors":"J. Collard, Jaclyn A. Lanham, B. Davis","doi":"10.1115/imece2021-71914","DOIUrl":"https://doi.org/10.1115/imece2021-71914","url":null,"abstract":"\u0000 In a previous study by Davis and Dequenne, a Holmquist-Johnson-Cook (HJC) constitutive model for a cellular concrete with a nominal density of 1442 kg/m3 was developed from existing direct tension, uniaxial strain, and triaxial shear testing conducted at the United States Army Corps of Engineers Engineer Research and Development Center (ERDC) and Sandia National Laboratory (SNL). The resulting constitutive model was compared to depth of penetration results from testing conducted by Goodman at the Aberdeen Test Center with promising results. This study seeks to build on this previous work by producing depth of penetration and perforation experiments using non-deforming projectiles into a similar cellular concrete for validation of the fit HJC model. Depth of penetration experiments were conducted by firing into a 305 mm thick panel over a velocity range of 200–800 m/s with the strike velocity and depth of penetration recorded for each experiment. Perforation experiments were conducted over a range of 200–800 m/s against panels with thicknesses of 38 mm, 76 mm, and 114 mm with the strike velocity, residual velocity, and crater characteristics recorded for each experiment. 2D numerical simulations were conducted for each experiment and the results were compared for initial model validation, but additional experimental testing and simulation is required. There is error between the experimental and numerical results and a sensitivity analysis should be conducted to determine where additional testing is appropriate to improve the model’s correlation with experimental results.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"459 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79818887","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}
Ankit Sharma, Akula Sai Pratyush, S. M, A. Gupta, R. Sujith
Excellent mechanical, electrical, and thermal properties of the sp2 hybridized carbon allotrope derivative of graphene nanoplatelets (GNP) make it a suitable reinforcement candidate for the metal matrix composite. Due to the superior properties of Al – Zn – Mg – Cu alloy, it is used as an armor material for decades in defense industries. In this study, Al – Zn – Mg – Cu alloy/GNP reinforced composite with varying weight fraction of 0, 0.5% & 1% GNP was fabricated via hot-pressing sintering. Initial investigation shows that the composites were densified, and the relative density was 99.64% after the fabrication process. Two-stage heat treatment was performed on the Al alloy, forming a stable η (MgZn2) phase. The DSC plots show the dissolution of the unstable η´ (Mg4Zn7) phase into the stable η (MgZn2) phase in between 450 °C – 480 °C and homogenized due to artificial aging process with the α-Al phase. Investigation showed an increment in the hardness of the heat-treated 0.5% GNP reinforced composite by 15.44%, and 8.92% in the heat-treated 1% GNP reinforced composite compared to their non-heat treated composites. The Field Emission Scanning Electron Microscopic images of samples before heat treatment show agglomeration of GNP and heterogeneous nucleation, and images after heat treatment show that GNP has been dispersed into the grains and grain boundaries alongside the eutectic phases, which restrict the dislocation motion and strengthen the matrix by grain boundary strengthening.
{"title":"Effect of Heat Treatment on Microstructure and Hardness of Graphene Nanoplatelets Reinforced Al-Zn-Mg-Cu Alloy Composite","authors":"Ankit Sharma, Akula Sai Pratyush, S. M, A. Gupta, R. Sujith","doi":"10.1115/imece2021-71258","DOIUrl":"https://doi.org/10.1115/imece2021-71258","url":null,"abstract":"\u0000 Excellent mechanical, electrical, and thermal properties of the sp2 hybridized carbon allotrope derivative of graphene nanoplatelets (GNP) make it a suitable reinforcement candidate for the metal matrix composite. Due to the superior properties of Al – Zn – Mg – Cu alloy, it is used as an armor material for decades in defense industries. In this study, Al – Zn – Mg – Cu alloy/GNP reinforced composite with varying weight fraction of 0, 0.5% & 1% GNP was fabricated via hot-pressing sintering. Initial investigation shows that the composites were densified, and the relative density was 99.64% after the fabrication process. Two-stage heat treatment was performed on the Al alloy, forming a stable η (MgZn2) phase. The DSC plots show the dissolution of the unstable η´ (Mg4Zn7) phase into the stable η (MgZn2) phase in between 450 °C – 480 °C and homogenized due to artificial aging process with the α-Al phase. Investigation showed an increment in the hardness of the heat-treated 0.5% GNP reinforced composite by 15.44%, and 8.92% in the heat-treated 1% GNP reinforced composite compared to their non-heat treated composites. The Field Emission Scanning Electron Microscopic images of samples before heat treatment show agglomeration of GNP and heterogeneous nucleation, and images after heat treatment show that GNP has been dispersed into the grains and grain boundaries alongside the eutectic phases, which restrict the dislocation motion and strengthen the matrix by grain boundary strengthening.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"2 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91422213","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. Abdelrahman, Slade C. Jewell, A. Elbella, S. J. Timpe
Polystyrene matrix nanocomposites were formulated using a custom nano particle consisting of nanodiamond covalently bonded to graphene oxide. Dispersion and mechanical property results for the nano composite are compared to those results for the neat polymer as well as for a nanocomposite infused with graphene oxide only. Dynamic light scattering was performed to determine the size of particles and the results showed that the custom nanoparticle reduced agglomeration by about 50% as compared to the graphene oxide alone. Microscale Vickers hardness testing revealed that neat polymer as well as the two nanocomposite samples all have similar hardness while nanoscale atomic force microscopy revealed that the neat polymer samples have the highest stiffness on average and the custom nanoparticle composite samples have the lowest stiffness. This difference in mechanical behavior with scale is attributed to local defects at the particle/matrix interface.
{"title":"Graphene Oxide / Nanodiamond Nanocomposites Characterized via Particle Dispersion and Micro- and Nanoscale Mechanical Properties","authors":"M. Abdelrahman, Slade C. Jewell, A. Elbella, S. J. Timpe","doi":"10.1115/imece2021-72137","DOIUrl":"https://doi.org/10.1115/imece2021-72137","url":null,"abstract":"\u0000 Polystyrene matrix nanocomposites were formulated using a custom nano particle consisting of nanodiamond covalently bonded to graphene oxide. Dispersion and mechanical property results for the nano composite are compared to those results for the neat polymer as well as for a nanocomposite infused with graphene oxide only. Dynamic light scattering was performed to determine the size of particles and the results showed that the custom nanoparticle reduced agglomeration by about 50% as compared to the graphene oxide alone. Microscale Vickers hardness testing revealed that neat polymer as well as the two nanocomposite samples all have similar hardness while nanoscale atomic force microscopy revealed that the neat polymer samples have the highest stiffness on average and the custom nanoparticle composite samples have the lowest stiffness. This difference in mechanical behavior with scale is attributed to local defects at the particle/matrix interface.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81724075","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 interaction between the CNT network and the surrounding polymer and between BP and the surrounding polymer occurs via interphase with different morphology than the bulk matrix. This interphase’s properties have not been given enough attention in the literature, and the purpose of this study is to investigate the interphase properties experimentally and analytically. Atomic Force Microscopy based Peak Force Quantitative Nanomechanics Mapping (PFQNM) technique with the high lateral resolution was used for the characterization of the interphase in 3-phase polymer matrix nano-composites at the nanoscale. Details of the calibration parameters such as probe stiffness, spring constant, tip radius, tapping force, deformation level, synchronous distance, drive3 amplitude sensitivity (DDS3), and deflection sensitivity were discussed. AFM Multimode 8, scanner type J with a maximum scanning window of 125μm × 125μm, was used. The Derjaguin, Muller, Toropov (DMT) equation was applied to the retract curve to calculate the elastic modulus. BP is heterogeneous at the nanoscale due to nonuniform resin impregnation. The average interphase thickness for the CNT network is 27nm in BP, higher than ∼10nm between epoxy and fiber, confirming stronger interphase. The CNT network size in BP nanocomposite is influenced by the inter-bundle and intra-bundle pores in the BP. The Kolarik, Quali, and Takayanagi models for interphase of the CNT network were investigated.
{"title":"Experimental Approach and Conventional Analytical Techniques to the Carbon Nanotube Network Interphase in 3-Phase Polymer Matrix Nano-Composites","authors":"Masoud Yekani Fard, Joel Swanstrom","doi":"10.1115/imece2021-70589","DOIUrl":"https://doi.org/10.1115/imece2021-70589","url":null,"abstract":"\u0000 The interaction between the CNT network and the surrounding polymer and between BP and the surrounding polymer occurs via interphase with different morphology than the bulk matrix. This interphase’s properties have not been given enough attention in the literature, and the purpose of this study is to investigate the interphase properties experimentally and analytically. Atomic Force Microscopy based Peak Force Quantitative Nanomechanics Mapping (PFQNM) technique with the high lateral resolution was used for the characterization of the interphase in 3-phase polymer matrix nano-composites at the nanoscale. Details of the calibration parameters such as probe stiffness, spring constant, tip radius, tapping force, deformation level, synchronous distance, drive3 amplitude sensitivity (DDS3), and deflection sensitivity were discussed. AFM Multimode 8, scanner type J with a maximum scanning window of 125μm × 125μm, was used. The Derjaguin, Muller, Toropov (DMT) equation was applied to the retract curve to calculate the elastic modulus. BP is heterogeneous at the nanoscale due to nonuniform resin impregnation. The average interphase thickness for the CNT network is 27nm in BP, higher than ∼10nm between epoxy and fiber, confirming stronger interphase. The CNT network size in BP nanocomposite is influenced by the inter-bundle and intra-bundle pores in the BP. The Kolarik, Quali, and Takayanagi models for interphase of the CNT network were investigated.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90457665","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}
Palladium hydride (Pd-H) is a metallic palladium that can absorb substantial amount of H at room temperature. Because this H absorption is recoverable, it can be utilized in a variety of energy applications. When Pd is alloyed with silver (Ag), sulfur poisoning remains a problem, but adding Ag improves Pd mechanical properties, boosts hydrogen permeability and solubility, and narrows the Pd-H system miscibility gap region. Pd alloyed with copper (Cu) has a lower H permeability and solubility compared to pure Pd and Pd-Ag alloys, but adding Cu gives better sulfur and carbon monoxide poisoning resistance and hydrogen embrittlement resistance, as well as better mechanical properties and a wider operating temperature range than pure Pd. These findings show that alloying Pd with a mix of Ag and Cu to make Pd-Ag-Cu ternary alloys improves Pd’s overall performance while also lowering its cost. Thus, in this paper, we provide the first embedded atom method potentials (EAM) for the quaternary hydrides Pd1-y-zAgyCuzHx. The EAM potentials can capture the preferred H occupancy locations, and determine the trends for the cohesive energies, lattice constants and elastic constants during MD simulations. The potentials also captured the existence of a miscibility gap for the Pd1-y-zAgyCuzHx and predicted it to narrow and disappear when Ag and Cu concentration increases, as was predicted by the experimental findings.
{"title":"Potentials for PdAgCu Metal Hydrides Energy Simulations","authors":"I. Hijazi, Chaonan Zhang, Robert Fuller","doi":"10.1115/imece2021-71494","DOIUrl":"https://doi.org/10.1115/imece2021-71494","url":null,"abstract":"\u0000 Palladium hydride (Pd-H) is a metallic palladium that can absorb substantial amount of H at room temperature. Because this H absorption is recoverable, it can be utilized in a variety of energy applications. When Pd is alloyed with silver (Ag), sulfur poisoning remains a problem, but adding Ag improves Pd mechanical properties, boosts hydrogen permeability and solubility, and narrows the Pd-H system miscibility gap region. Pd alloyed with copper (Cu) has a lower H permeability and solubility compared to pure Pd and Pd-Ag alloys, but adding Cu gives better sulfur and carbon monoxide poisoning resistance and hydrogen embrittlement resistance, as well as better mechanical properties and a wider operating temperature range than pure Pd. These findings show that alloying Pd with a mix of Ag and Cu to make Pd-Ag-Cu ternary alloys improves Pd’s overall performance while also lowering its cost. Thus, in this paper, we provide the first embedded atom method potentials (EAM) for the quaternary hydrides Pd1-y-zAgyCuzHx. The EAM potentials can capture the preferred H occupancy locations, and determine the trends for the cohesive energies, lattice constants and elastic constants during MD simulations. The potentials also captured the existence of a miscibility gap for the Pd1-y-zAgyCuzHx and predicted it to narrow and disappear when Ag and Cu concentration increases, as was predicted by the experimental findings.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81430963","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}
P. Capela, S. Carvalho, S. Costa, S. Souza, M. Pereira, L. Carvalho, J. Gomes, D. Soares
Grinding wheels are used in manufacturing industry to shape and finish different types of materials. To achieve this purpose, the wear resistance of grinding materials and the capacity to promote wear on the opposing surface determine the performance of the grinding part. During the grinding operations high temperatures are developed in the wheel/piece contact which can cause several problems like working material microstructural changes, internal defects (fissures...). In the last years, superficial structured wheels have been developed in order to reduce contact temperature and improve the grinding efficiency and the quality of the produced surface. In this work, two types of channels structures were produced on the surface of a vitrified alumina abrasive composite with: hexagonal and spiral geometries (active area of 95.3 and 91.6%, respectively). The obtained composites produced were characterized in terms of physical properties (density and porosity) and geometric channel features. In order to evaluate the changes on the wear rate and surface morphology pin-on-disc wear tests were performed under lubricated conditions at constant load (20 N) and sliding speed (0.5 m.s−1), at room temperature. An alumina rod (∅5 mm) was used as counterface material creating particularly hard contact conditions. The wear rate of both mating surfaces was measured by gravimetric method. The worn surfaces were characterized by SEM analysis and the tribological results were correlated with the physical properties of the composites and the introduced cooling channels. The dominant wear mechanisms, as identified by SEM analysis, were fine scale abrasive wear of the protruding load carrying particles, which is featured by the formation of wear flats, together with debonding of ceramic particles from the composite contact surface. Comparing with traditional wheels (without cooling channels), a decrease of the wear rate on disc side of 35 and 42% was obtained for, respectively, spiral and hexagonal channel geometries. On the alumina opposite counterface, the wear rate increases 10 and 47% for, respectively, hexagonal and spiral geometries. A significant improvement on the abrasive performance (a wear rate decreases on the abrasive wheel and an increase on the counterface) was achieved with the addition of the two types of channel geometries. The best combination of results (composite and counterface) was obtained for the spiral configuration of the cooling channels (grinding ratio of 0.86).
{"title":"Wear Behavior of Grinding Wheels With Superficial Cooling Channels","authors":"P. Capela, S. Carvalho, S. Costa, S. Souza, M. Pereira, L. Carvalho, J. Gomes, D. Soares","doi":"10.1115/imece2021-72319","DOIUrl":"https://doi.org/10.1115/imece2021-72319","url":null,"abstract":"\u0000 Grinding wheels are used in manufacturing industry to shape and finish different types of materials. To achieve this purpose, the wear resistance of grinding materials and the capacity to promote wear on the opposing surface determine the performance of the grinding part. During the grinding operations high temperatures are developed in the wheel/piece contact which can cause several problems like working material microstructural changes, internal defects (fissures...). In the last years, superficial structured wheels have been developed in order to reduce contact temperature and improve the grinding efficiency and the quality of the produced surface.\u0000 In this work, two types of channels structures were produced on the surface of a vitrified alumina abrasive composite with: hexagonal and spiral geometries (active area of 95.3 and 91.6%, respectively). The obtained composites produced were characterized in terms of physical properties (density and porosity) and geometric channel features. In order to evaluate the changes on the wear rate and surface morphology pin-on-disc wear tests were performed under lubricated conditions at constant load (20 N) and sliding speed (0.5 m.s−1), at room temperature. An alumina rod (∅5 mm) was used as counterface material creating particularly hard contact conditions. The wear rate of both mating surfaces was measured by gravimetric method. The worn surfaces were characterized by SEM analysis and the tribological results were correlated with the physical properties of the composites and the introduced cooling channels. The dominant wear mechanisms, as identified by SEM analysis, were fine scale abrasive wear of the protruding load carrying particles, which is featured by the formation of wear flats, together with debonding of ceramic particles from the composite contact surface. Comparing with traditional wheels (without cooling channels), a decrease of the wear rate on disc side of 35 and 42% was obtained for, respectively, spiral and hexagonal channel geometries. On the alumina opposite counterface, the wear rate increases 10 and 47% for, respectively, hexagonal and spiral geometries. A significant improvement on the abrasive performance (a wear rate decreases on the abrasive wheel and an increase on the counterface) was achieved with the addition of the two types of channel geometries. The best combination of results (composite and counterface) was obtained for the spiral configuration of the cooling channels (grinding ratio of 0.86).","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85344998","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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