Multi-scale modelling is a cornerstone for the relatively new class of hierarchical materials which can perform multifunctional tasks, owing to their electrical, magnetic or thermal properties. Careful design strategies are to be devised, in-order to maintain their multi-functionality over the expected range of operation. In this study, we focus on these materials, which can be manufactured using a specialized technique of additive manufacturing, known as fused deposition modelling (FDM), owing to its flexibility and compatibility, working with polymer based materials. A review has been made on the various parameters affecting the manufacturing process, and how these variations can affect the properties of the end product. Future research directions are also pointed out, including stimuli responsive printing technique, popularly known as 4D printing and integration of neural networks into the manufacturing process which can improve the overall design lifecycle efficiency. This can involve autonomous production of test specimen, and revert back the data for model improvement, thereby enhancing predictive capabilities. The major focus of this work is on how we can use our current knowledge and techniques in the design of efficient and effective multifunctional composite materials from the bottoms-up approach.
{"title":"Multiscale Modelling of Multifunctional Composites: A Review","authors":"S. Suresh Babu, A. Mourad","doi":"10.1115/imece2021-73276","DOIUrl":"https://doi.org/10.1115/imece2021-73276","url":null,"abstract":"\u0000 Multi-scale modelling is a cornerstone for the relatively new class of hierarchical materials which can perform multifunctional tasks, owing to their electrical, magnetic or thermal properties. Careful design strategies are to be devised, in-order to maintain their multi-functionality over the expected range of operation. In this study, we focus on these materials, which can be manufactured using a specialized technique of additive manufacturing, known as fused deposition modelling (FDM), owing to its flexibility and compatibility, working with polymer based materials. A review has been made on the various parameters affecting the manufacturing process, and how these variations can affect the properties of the end product. Future research directions are also pointed out, including stimuli responsive printing technique, popularly known as 4D printing and integration of neural networks into the manufacturing process which can improve the overall design lifecycle efficiency. This can involve autonomous production of test specimen, and revert back the data for model improvement, thereby enhancing predictive capabilities. The major focus of this work is on how we can use our current knowledge and techniques in the design of efficient and effective multifunctional composite materials from the bottoms-up approach.","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":"83001475","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}
C. Fais, Muhammad Ali, Isaiah Yasko, R. Walker, A. Lutfullaeva
This paper presents experimental performance characteristics of fixed-geometry hydrodynamic thrust bearings machined to different helical taper depths. Theoretical analysis based on the Reynold’s equation states that under favorable conditions, these taper depths can produce and maintain load-supporting hydrodynamic pressure yet result in characteristically different oil-film pressure distribution profiles and magnitudes of friction torque. These characteristic performance indicators have not previously been observed experimentally for unidirectional fixed-geometry hydrodynamic thrust bearings with helically tapered pads. An experimental test rig was developed by re-purposing a horizontal milling machine capable of subjecting the test bearings to speeds up to 1,265 rpm and axial loads up to 250 lbf (1,112 N). Under various combinations of constant speed, load, and lubrication supply conditions, the steady-state oil-film pressure distribution across the bearing pad and active friction torque are measured. The effects of variable taper-depth on hydrodynamic pressure distribution and friction torque are compared and discussed.
{"title":"Experimental Performance Evaluation of Fixed-Geometry Hydrodynamic Thrust Bearings With Variable Taper Depths","authors":"C. Fais, Muhammad Ali, Isaiah Yasko, R. Walker, A. Lutfullaeva","doi":"10.1115/imece2021-70459","DOIUrl":"https://doi.org/10.1115/imece2021-70459","url":null,"abstract":"\u0000 This paper presents experimental performance characteristics of fixed-geometry hydrodynamic thrust bearings machined to different helical taper depths. Theoretical analysis based on the Reynold’s equation states that under favorable conditions, these taper depths can produce and maintain load-supporting hydrodynamic pressure yet result in characteristically different oil-film pressure distribution profiles and magnitudes of friction torque. These characteristic performance indicators have not previously been observed experimentally for unidirectional fixed-geometry hydrodynamic thrust bearings with helically tapered pads. An experimental test rig was developed by re-purposing a horizontal milling machine capable of subjecting the test bearings to speeds up to 1,265 rpm and axial loads up to 250 lbf (1,112 N). Under various combinations of constant speed, load, and lubrication supply conditions, the steady-state oil-film pressure distribution across the bearing pad and active friction torque are measured. The effects of variable taper-depth on hydrodynamic pressure distribution and friction torque are compared and discussed.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78717245","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}
A. Bhardwaj, N. Gohil, A. Sharma, K. Lakshman Rao, A. Gupta, S. Kumar
Ti6Al4V sheet metal has found significant applications in the aerospace, defence and biomedical sectors due to its high strength-to-weight ratio and excellent corrosion resistance. The texture plays an important role in tailoring the mechanical properties which can be modified via thermo-mechanical processing. Constrained groove pressing (CGP) is a well-known sheet metal severe plastic deformation (SPD) technique for grain refinement and enhancement of mechanical properties. In this work, high temperature CGP has been performed successfully on Ti6Al4V alloy at 550°C followed by heat treatment at 500°C. CGP and heat treatment led to grain refinement and formation of submicron size grains. The inverse pole figure (IPF) reveals the decrease in texture intensity of basal planes from 5.9 to 4.5 in CGPed Ti6Al4V. Heat treatment further reduced the IPF texture intensity to 3.5. Enhancement in mechanical properties such as YS, UTS and microhardness is also observed. Although slight enhancement is observed in yield strength, ultimate tensile strength has been improved by 21% after CGP and heat treatment. Up to 20% improvements in microhardness have also been observed in processed samples. CGP and heat treatment together can serve as an efficient technique for tailoring microtexture and mechanical properties of Ti6Al4V and other HCP alloys.
{"title":"EBSD Investigation of Ti6Al4V Alloy Processed by Constrained Groove Pressing and Heat Treatment","authors":"A. Bhardwaj, N. Gohil, A. Sharma, K. Lakshman Rao, A. Gupta, S. Kumar","doi":"10.1115/imece2021-70393","DOIUrl":"https://doi.org/10.1115/imece2021-70393","url":null,"abstract":"\u0000 Ti6Al4V sheet metal has found significant applications in the aerospace, defence and biomedical sectors due to its high strength-to-weight ratio and excellent corrosion resistance. The texture plays an important role in tailoring the mechanical properties which can be modified via thermo-mechanical processing. Constrained groove pressing (CGP) is a well-known sheet metal severe plastic deformation (SPD) technique for grain refinement and enhancement of mechanical properties. In this work, high temperature CGP has been performed successfully on Ti6Al4V alloy at 550°C followed by heat treatment at 500°C. CGP and heat treatment led to grain refinement and formation of submicron size grains. The inverse pole figure (IPF) reveals the decrease in texture intensity of basal planes from 5.9 to 4.5 in CGPed Ti6Al4V. Heat treatment further reduced the IPF texture intensity to 3.5. Enhancement in mechanical properties such as YS, UTS and microhardness is also observed. Although slight enhancement is observed in yield strength, ultimate tensile strength has been improved by 21% after CGP and heat treatment. Up to 20% improvements in microhardness have also been observed in processed samples. CGP and heat treatment together can serve as an efficient technique for tailoring microtexture and mechanical properties of Ti6Al4V and other HCP alloys.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74166285","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 creation of large objects by additive manufacturing is something that is desired, but often is unachievable due to the size of the object and capacity of the 3D printer used. To address this issue various techniques on part segmentation have been implemented, including origami, geometric segmentation, and segmentation with manufacturability. However, joining or connecting those segmented or discretized additive manufactured parts can be an issue. In this paper we propose to use fabric as a flexible joint and segment carrier when creating larger objects by additive manufacturing. Specifically, flat simply segmented parts of the desired large object will be additive manufactured on top of a fabric as to adhere the two. Three different fabrics, cotton duck cloth, acrylic-dyed and ripstop, were considered to investigate the interfacial strength with 3D printed PLA. Both treated and untreated fabrics are prepared simultaneously so that parts can be printed on top of them at a predefined spatial location. After the fabrication of segments, adhesion force between the segment and the fabrics are tested with mechanical adhesion tests. We found that untreated cotton duck cloth had an average 78% higher adhesion than other samples. When glue was used to treat fabric before printing a weaker bond between the tri-layer, fabric-glue-PLA sandwich was observed comparative to untreated fabrics. The interfacial strength of 3D printed part printed on fabric can be enhanced by changing print parameters, fiber morphology and fabric properties, and surface modification of fabrics. In this work the fiber morphology and fabric properties show significant impact on the interfacial strength. Adhesion forces desired between fabric and 3D printed part can be tailored per specific large object as needed, per segmentation, using this information. The proposed method can help with the fabrication of multifaceted single objects with localized optimum process parameters which can address the directional anisotropic nature of AM parts and corresponding non-homogeneous performance.
{"title":"Thermoplastics 3D Printing Using Fused Deposition Modeling on Fabrics","authors":"Maxwell Blais, Scott M Tomlinson, Bashir Khoda","doi":"10.1115/imece2021-69695","DOIUrl":"https://doi.org/10.1115/imece2021-69695","url":null,"abstract":"\u0000 The creation of large objects by additive manufacturing is something that is desired, but often is unachievable due to the size of the object and capacity of the 3D printer used. To address this issue various techniques on part segmentation have been implemented, including origami, geometric segmentation, and segmentation with manufacturability. However, joining or connecting those segmented or discretized additive manufactured parts can be an issue. In this paper we propose to use fabric as a flexible joint and segment carrier when creating larger objects by additive manufacturing. Specifically, flat simply segmented parts of the desired large object will be additive manufactured on top of a fabric as to adhere the two. Three different fabrics, cotton duck cloth, acrylic-dyed and ripstop, were considered to investigate the interfacial strength with 3D printed PLA. Both treated and untreated fabrics are prepared simultaneously so that parts can be printed on top of them at a predefined spatial location. After the fabrication of segments, adhesion force between the segment and the fabrics are tested with mechanical adhesion tests. We found that untreated cotton duck cloth had an average 78% higher adhesion than other samples. When glue was used to treat fabric before printing a weaker bond between the tri-layer, fabric-glue-PLA sandwich was observed comparative to untreated fabrics. The interfacial strength of 3D printed part printed on fabric can be enhanced by changing print parameters, fiber morphology and fabric properties, and surface modification of fabrics. In this work the fiber morphology and fabric properties show significant impact on the interfacial strength. Adhesion forces desired between fabric and 3D printed part can be tailored per specific large object as needed, per segmentation, using this information. The proposed method can help with the fabrication of multifaceted single objects with localized optimum process parameters which can address the directional anisotropic nature of AM parts and corresponding non-homogeneous performance.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74742448","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}
Alyaqadhan Allamki, M. Al-Maharbi, R. Arunachalam, Sayyad Zahid Qamar
The aluminum-magnesium-silicon alloy 6201-T81 is a popular electrical conductor, widely used for overhead and distribution lines. Its light weight makes its mass conductivity twice that of copper. Aluminum conductors however experience creep, corrosion, power loss, and other drawbacks. Therefore, it has become a necessity for manufacturers to improve mechanical and electrical properties. The alloy 6201-T81 is an age hardenable alloy, in which a controlled precipitation of Mg2Si is performed through two different successive heat treatments: Solution heat treatment and precipitation heat treatment. ∅ 3.5 mm wires of the alloy were solution heat treated at 510 °C for an hour, quenched in ice water, and precipitation heat treated at the temperature range 150–200°C for the time range 2–24 h. Results show that strength and hardness increase with aging time at the precipitation heat treatment temperatures 150 °C, 165 °C, and 175 °C, but decreased with aging time at 185 °C and 200 °C. The increase was due to the precipitation of finely and uniformly coherent needle-like Mg2Si precipitates, β″. The decrease was due to the precipitation of the semi-coherent and incoherent rod-like Mg2Si precipitates β′ and β, respectively. Electrical conductivity increases with the aging temperature and time. Maximum conductivity was 60 %IACS obtained after treatments (185°C, 18h), (200 °C, 13h), and (200 °C, 24h. Optimum mechanical properties were obtained after the treatment (165 °C, 18 h) (313 MPa, 8%, 95 HV, and 57.7 %IACS). Optical micrographs verified the correlation between the microstructural grain size and both the mechanical and electrical properties.
{"title":"Improved Tensile Strength and Electrical Conductivity of the Electrical Conductor Aluminum Alloy 6201","authors":"Alyaqadhan Allamki, M. Al-Maharbi, R. Arunachalam, Sayyad Zahid Qamar","doi":"10.1115/imece2021-70245","DOIUrl":"https://doi.org/10.1115/imece2021-70245","url":null,"abstract":"\u0000 The aluminum-magnesium-silicon alloy 6201-T81 is a popular electrical conductor, widely used for overhead and distribution lines. Its light weight makes its mass conductivity twice that of copper. Aluminum conductors however experience creep, corrosion, power loss, and other drawbacks. Therefore, it has become a necessity for manufacturers to improve mechanical and electrical properties. The alloy 6201-T81 is an age hardenable alloy, in which a controlled precipitation of Mg2Si is performed through two different successive heat treatments: Solution heat treatment and precipitation heat treatment. ∅ 3.5 mm wires of the alloy were solution heat treated at 510 °C for an hour, quenched in ice water, and precipitation heat treated at the temperature range 150–200°C for the time range 2–24 h. Results show that strength and hardness increase with aging time at the precipitation heat treatment temperatures 150 °C, 165 °C, and 175 °C, but decreased with aging time at 185 °C and 200 °C. The increase was due to the precipitation of finely and uniformly coherent needle-like Mg2Si precipitates, β″. The decrease was due to the precipitation of the semi-coherent and incoherent rod-like Mg2Si precipitates β′ and β, respectively. Electrical conductivity increases with the aging temperature and time. Maximum conductivity was 60 %IACS obtained after treatments (185°C, 18h), (200 °C, 13h), and (200 °C, 24h. Optimum mechanical properties were obtained after the treatment (165 °C, 18 h) (313 MPa, 8%, 95 HV, and 57.7 %IACS). Optical micrographs verified the correlation between the microstructural grain size and both the mechanical and electrical properties.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89795758","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}
Md. Didarul Islam, Sipan Liu, J. Derov, A. Urbas, Z. Ku, Amy Sihn, Evan M. Smith, D. Boyd, Woohong Kim, J. Sanghera, V. Nguyen, J. Myers, C. Baker, J. Ryu
Mid-wavelength infrared (MWIR, λ = 3–5 μm) materials are of great importance due to their applications in optical sensors and devices for military, industry, and non-invasive medical diagnostics. Specifically, MWIR polarimetry has significantly improved biometric recognition and camouflaged detection. Most commercial polarizers are based on expensive inorganic materials that are heavy, fragile, and brittle. Thus a suitable polymeric material for MWIR optics is highly desired. Herein, sulfur-based organically modified chalcogenides (ORMOCHALC) polymers have been utilized to fabricate MWIR polarizers by a simple thermal imprinting method followed by Ay deposition. A parametric study to choose suitable geometry for the polarizer was conducted, and highly efficient devices were designed that possess competitive extinction coefficients to the commercial polarizers. However, a significant limitation of the ORMOCHALC polymer is that to increase the refractive index of the polymer, the chalcogenide (i.e., S) content needs to be increased, which results in reduced Young’s modulus and lower glass transition temperature. This decayed thermomechanical stability compromises the structural integrity of ORMOCHALC optical devices. In addition to polymeric MWIR polarizer fabrication, composite materials were also synthesized and characterized for future MWIR device fabrications. Poly(S-r-DIB) was reinforced with zinc sulfide nanoparticles to simultaneously improve the refractive index and the thermomechanical properties. The addition of ZnS nanoparticles significantly improved the glass transition temperature (Tg) of the ORMOCHALC (9.6 °C to 31.4 °C), and the refractive index (Δn = 6.6 %). Then, a figure of merit subwavelength wire-grid polarizers was also analyzed based on the optically and mechanically reinforced composites. If fabricated, nanoparticles reinforced polarizers will possess superior structural integrity due to higher glass transition temperature. Moreover, the polarizers show a spectral selectivity as the resonance wavelength of the transmitted-reflected curve was redshifted to larger wavelengths for ZnS reinforced ORMOCHALC composite. These polarizers with superior extinction coefficient, spectral selectivity, and improved thermomechanical stability demonstrate a border implementation opportunity in the MWIR optics.
{"title":"Highly Efficient Mid-Wavelength Infrared (MWIR) Polarizer by ORMOCHALC Composite With Improved Thermomechanical Stability and Spectral Selectivity","authors":"Md. Didarul Islam, Sipan Liu, J. Derov, A. Urbas, Z. Ku, Amy Sihn, Evan M. Smith, D. Boyd, Woohong Kim, J. Sanghera, V. Nguyen, J. Myers, C. Baker, J. Ryu","doi":"10.1115/imece2021-70843","DOIUrl":"https://doi.org/10.1115/imece2021-70843","url":null,"abstract":"\u0000 Mid-wavelength infrared (MWIR, λ = 3–5 μm) materials are of great importance due to their applications in optical sensors and devices for military, industry, and non-invasive medical diagnostics. Specifically, MWIR polarimetry has significantly improved biometric recognition and camouflaged detection. Most commercial polarizers are based on expensive inorganic materials that are heavy, fragile, and brittle. Thus a suitable polymeric material for MWIR optics is highly desired. Herein, sulfur-based organically modified chalcogenides (ORMOCHALC) polymers have been utilized to fabricate MWIR polarizers by a simple thermal imprinting method followed by Ay deposition. A parametric study to choose suitable geometry for the polarizer was conducted, and highly efficient devices were designed that possess competitive extinction coefficients to the commercial polarizers. However, a significant limitation of the ORMOCHALC polymer is that to increase the refractive index of the polymer, the chalcogenide (i.e., S) content needs to be increased, which results in reduced Young’s modulus and lower glass transition temperature. This decayed thermomechanical stability compromises the structural integrity of ORMOCHALC optical devices. In addition to polymeric MWIR polarizer fabrication, composite materials were also synthesized and characterized for future MWIR device fabrications. Poly(S-r-DIB) was reinforced with zinc sulfide nanoparticles to simultaneously improve the refractive index and the thermomechanical properties. The addition of ZnS nanoparticles significantly improved the glass transition temperature (Tg) of the ORMOCHALC (9.6 °C to 31.4 °C), and the refractive index (Δn = 6.6 %). Then, a figure of merit subwavelength wire-grid polarizers was also analyzed based on the optically and mechanically reinforced composites. If fabricated, nanoparticles reinforced polarizers will possess superior structural integrity due to higher glass transition temperature. Moreover, the polarizers show a spectral selectivity as the resonance wavelength of the transmitted-reflected curve was redshifted to larger wavelengths for ZnS reinforced ORMOCHALC composite. These polarizers with superior extinction coefficient, spectral selectivity, and improved thermomechanical stability demonstrate a border implementation opportunity in the MWIR optics.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"121 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83411250","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}
Elastomer materials are often used for components such as tire treads or hydraulic sealings, when deformable and damping behavior of components are desired and high dynamic loads appear. Such elastomers show time- and frequency-dependent characteristics, called viscoelasticity. The modelling of viscoelastic material is mainly implemented in simulations by rheological models, which often consists of elastic and damping elements. A viscoelastic model can be parametrized to experimental data to describe a specific elastomer with high accuracy. The most common model is the Prony-series. This model uses several Maxwell-branches (connection of one elastic and one damping element in series). Every branch is only able to fit the experimental behavior at one single excitation frequency. This fact makes it necessary to use a lot of parameters for adapting the frequency- and temperature-dependent characteristics over decades of the excitation frequency. To overcome this need for a huge amount of parameters we formulate a fractional viscoelastic model approach that gets along with a much smaller set of parameters, using finite elements. In order to reduce the numerical effort, a similarly formulated model is set up on force-displacement level additionally. In this way, the complexity of the simulation can be reduced with mapping of the material behavior.
{"title":"Modelling the Time-Dependent Behavior of Elastomers Using Fractional Viscoelastic Material Formulations","authors":"A. Leenders, Hamed Vahdati Zadeh, M. Wangenheim","doi":"10.1115/imece2021-71178","DOIUrl":"https://doi.org/10.1115/imece2021-71178","url":null,"abstract":"\u0000 Elastomer materials are often used for components such as tire treads or hydraulic sealings, when deformable and damping behavior of components are desired and high dynamic loads appear. Such elastomers show time- and frequency-dependent characteristics, called viscoelasticity. The modelling of viscoelastic material is mainly implemented in simulations by rheological models, which often consists of elastic and damping elements. A viscoelastic model can be parametrized to experimental data to describe a specific elastomer with high accuracy. The most common model is the Prony-series. This model uses several Maxwell-branches (connection of one elastic and one damping element in series). Every branch is only able to fit the experimental behavior at one single excitation frequency. This fact makes it necessary to use a lot of parameters for adapting the frequency- and temperature-dependent characteristics over decades of the excitation frequency.\u0000 To overcome this need for a huge amount of parameters we formulate a fractional viscoelastic model approach that gets along with a much smaller set of parameters, using finite elements. In order to reduce the numerical effort, a similarly formulated model is set up on force-displacement level additionally. In this way, the complexity of the simulation can be reduced with mapping of the material behavior.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85761931","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}
A configuration of a plain (sliding) bearing system is the use of a reinforced fabric comprising a woven structure of polytetrafluoroethylene (PTFE) and other fibers integrated with a phenolic resin system used to both encapsulate the fibrous materials and provide adhesion to metallic and other substrates. This construction promotes dimensional stability and improves thermal conductivity. These PTFE linings offer exceptionally low coefficient friction. The bushing is recommended for high loads when combined with low surface speeds. These fully self-lubricating bushings offer good contamination resistance, no stick-slip and excellent cold flow resistance. This technique has shown longer life of 7 to 10 times that of standard steel-backed, bronze-sintered and PTFE overlay. Proprietary self-lubricating PTFE fibers are applied directly to the steel. This polytetrafluoroethylene is woven onsite and applied directly to the steel. The woven liner is compressible and able to absorb distortions in mating surfaces. PTFE fabrics processed with phenolic resins can entrap air within the cured fabric liner. The entrapped air has the potential to affect bearing performance by reduction of bonding area and reduction in load carrying capabilities. Air release agents can be used to limit the amount of air entrapment within the liner system. The intent of this research is to determine what, if any, affect the addition of commercially available air release agents would have on PTFE bearing performance. Experimental wear testing at various static and dynamic bearing conditions with and without contamination (de-ice fluid), including at high temperature (325°F) were conducted on eighteen specimens. Peel strength test were also conducted. All these tests were conducted based on prevalent industry standards. Parameters of static load resistance (deflection and permanent set) and loaded torque were found to be unaffected by the use of an air release agent when compared to baseline articles manufactured without such air releasing agents. Results showed that by integration of a commercially available air release agent into the processing of a PTFE based, phenolic resin bearing liner system, one can reduce variability and help stabilize wear performance. Specimens prepared with air release agent showed improved oscillation (fatigue) test results. Further, air release agent also resulted in a 35% increase in peel strength performance when tested per industry standard methods. Contamination with de-ice fluid showed no negative performance results. While the investigations here used only one ratio of additive among all tested bearings, but other concentrations are possible. Authors would like to pursue additional studies in future to determine the amount of air release agent that can reliably be added to remove the maximum air release without affecting the overall bearing performance. By finding this, a threshold of additive can also be determined.
{"title":"Effect of Air Release Agents on Performance Results of Fabric Lined Bushings","authors":"C. Sahay, Suhash Ghosh, M. Mormino","doi":"10.1115/IMECE2020-24464","DOIUrl":"https://doi.org/10.1115/IMECE2020-24464","url":null,"abstract":"\u0000 A configuration of a plain (sliding) bearing system is the use of a reinforced fabric comprising a woven structure of polytetrafluoroethylene (PTFE) and other fibers integrated with a phenolic resin system used to both encapsulate the fibrous materials and provide adhesion to metallic and other substrates. This construction promotes dimensional stability and improves thermal conductivity. These PTFE linings offer exceptionally low coefficient friction. The bushing is recommended for high loads when combined with low surface speeds. These fully self-lubricating bushings offer good contamination resistance, no stick-slip and excellent cold flow resistance. This technique has shown longer life of 7 to 10 times that of standard steel-backed, bronze-sintered and PTFE overlay. Proprietary self-lubricating PTFE fibers are applied directly to the steel. This polytetrafluoroethylene is woven onsite and applied directly to the steel. The woven liner is compressible and able to absorb distortions in mating surfaces. PTFE fabrics processed with phenolic resins can entrap air within the cured fabric liner. The entrapped air has the potential to affect bearing performance by reduction of bonding area and reduction in load carrying capabilities. Air release agents can be used to limit the amount of air entrapment within the liner system.\u0000 The intent of this research is to determine what, if any, affect the addition of commercially available air release agents would have on PTFE bearing performance. Experimental wear testing at various static and dynamic bearing conditions with and without contamination (de-ice fluid), including at high temperature (325°F) were conducted on eighteen specimens. Peel strength test were also conducted. All these tests were conducted based on prevalent industry standards. Parameters of static load resistance (deflection and permanent set) and loaded torque were found to be unaffected by the use of an air release agent when compared to baseline articles manufactured without such air releasing agents. Results showed that by integration of a commercially available air release agent into the processing of a PTFE based, phenolic resin bearing liner system, one can reduce variability and help stabilize wear performance. Specimens prepared with air release agent showed improved oscillation (fatigue) test results. Further, air release agent also resulted in a 35% increase in peel strength performance when tested per industry standard methods. Contamination with de-ice fluid showed no negative performance results. While the investigations here used only one ratio of additive among all tested bearings, but other concentrations are possible. Authors would like to pursue additional studies in future to determine the amount of air release agent that can reliably be added to remove the maximum air release without affecting the overall bearing performance. By finding this, a threshold of additive can also be determined.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75186236","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}
Protein-based drug carriers are promising candidates for efficient drug delivery among the available potential colloidal carrier systems, due to their low cytotoxicity, abundance, renewability, diverse functional groups and interactions, and high drug loading capacity, etc. In this study, molecular dynamics (MD) simulations are performed to study the mechanisms of 11S molecule of soy protein as drug delivery vehicle to attach allyl isothiocyanate (AITC) and doxorubicin (DOX) drugs. The intermolecular interactions between protein and drugs are investigated; and the loading capacities of the protein molecules are calculated and compared with experiments. It is found that, for the AITC system, both nonpolar and polar residues of protein have the ability to adsorb AITCs; particularly, the polar residues serve as the primary active sites for the stable attachment of the drug molecules through the electrostatic (dipole-dipole) interactions. For the DOX system, however, the main driving force become the π-π stacking (the van der Waals interactions) among the aromatic rings of DOX and protein. In addition to pristine protein, different denaturation processes are found to be able to increase the exposure of active sites, therefore, enhance the loading efficiency of the protein carriers.
{"title":"Molecular Dynamic Simulation Study on Soy Protein As Drug Delivery Vehicle","authors":"Zhuoyuan Zheng, Akash Singh, Yumeng Li","doi":"10.1115/IMECE2020-23590","DOIUrl":"https://doi.org/10.1115/IMECE2020-23590","url":null,"abstract":"\u0000 Protein-based drug carriers are promising candidates for efficient drug delivery among the available potential colloidal carrier systems, due to their low cytotoxicity, abundance, renewability, diverse functional groups and interactions, and high drug loading capacity, etc. In this study, molecular dynamics (MD) simulations are performed to study the mechanisms of 11S molecule of soy protein as drug delivery vehicle to attach allyl isothiocyanate (AITC) and doxorubicin (DOX) drugs. The intermolecular interactions between protein and drugs are investigated; and the loading capacities of the protein molecules are calculated and compared with experiments. It is found that, for the AITC system, both nonpolar and polar residues of protein have the ability to adsorb AITCs; particularly, the polar residues serve as the primary active sites for the stable attachment of the drug molecules through the electrostatic (dipole-dipole) interactions. For the DOX system, however, the main driving force become the π-π stacking (the van der Waals interactions) among the aromatic rings of DOX and protein. In addition to pristine protein, different denaturation processes are found to be able to increase the exposure of active sites, therefore, enhance the loading efficiency of the protein carriers.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78121199","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 traditional way of designing materials, including experimental measurement and computational simulation, are not efficient. Machine learning is considered a promising solution for material design in the recent years. By observing from previous data, machine learning finds patterns, learns from the patterns and predict the material properties. In this study, machine learning methods are used for discovering new cathode with better properties, includes crystal system learning and the property prediction. K-Folder cross-validation is used for finding the best training data with a limited dataset, nevertheless increasing the percentage of training data would ultimately result in better performance on prediction. It is found that, random forest gives the highest average accuracy in crystal system classification, meanwhile, extra randomized tree algorithm provides a higher averaged coefficient of determination and lower mean squared error in the regression model predicting electrical properties of cathodes. The random forest algorithm is chosen from a wide range of machine learning algorithms with the implementation of Monte Carlo validation. Based on the feature importance evaluation, oxygen contents are found to have the highest effects in determining capacity gravity and volume change in properties prediction.
{"title":"Machine Learning Assisted Design for Active Cathode Materials","authors":"S. Yong, Zhuoyuan Zheng, Pingfeng Wang, Yumeng Li","doi":"10.1115/IMECE2020-23963","DOIUrl":"https://doi.org/10.1115/IMECE2020-23963","url":null,"abstract":"\u0000 The traditional way of designing materials, including experimental measurement and computational simulation, are not efficient. Machine learning is considered a promising solution for material design in the recent years. By observing from previous data, machine learning finds patterns, learns from the patterns and predict the material properties. In this study, machine learning methods are used for discovering new cathode with better properties, includes crystal system learning and the property prediction. K-Folder cross-validation is used for finding the best training data with a limited dataset, nevertheless increasing the percentage of training data would ultimately result in better performance on prediction. It is found that, random forest gives the highest average accuracy in crystal system classification, meanwhile, extra randomized tree algorithm provides a higher averaged coefficient of determination and lower mean squared error in the regression model predicting electrical properties of cathodes. The random forest algorithm is chosen from a wide range of machine learning algorithms with the implementation of Monte Carlo validation. Based on the feature importance evaluation, oxygen contents are found to have the highest effects in determining capacity gravity and volume change in properties prediction.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86039851","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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