Wood plastic composite materials have shown a remarkable performance in various applications due to its inherent properties like strength, durability, and lightweight over conventional composite materials. However, utilization of wood as an organic filler for polymers poses a serious negative impact to the green areas. Therefore, utilization of agro-residues as organic fillers instead of wood offers a sustainable solution to the aforementioned problem. In this context, this study aims to investigate the potential use of date palm pedicel agro-residues as natural fillers in eco-composites in which recycled post-consumer polypropylene is used as a matrix. Three levels of date palm flour content, namely, 10 v.%, 20 v.% and 30 v.% are used. The influence of the date palm pedicels flour content on the mechanical, physical and thermal behavior of the developed eco-composites is examined. Material properties of the fabricated eco-composites are characterized experimentally according to ASTM standards. Thermogravimetric analysis (TGA) is also performed to assess the thermal decomposition of the developed composites. Moreover, the morphology of fractured regions is captured using Scanning Electron Microscope (SEM). Generally, adding natural fillers to the polymer matrix is a cost effective option. However, it also slightly affects tensile strength, elongation, and flexural strength at break and enhance the Young’s modulus compared to the neat polypropylene. Interestingly, it is observed that the recycled polypropylene based composites are more repellent to water absorption in comparison to the virgin polypropylene-based composites. This attribute might be due to the surface quality transformation for the reprocessed plastic polymer.
{"title":"Development of New Eco-Composites From Natural Agro-Residues and Recycled Polymers","authors":"K. Alzebdeh, M. Nassar, Nasr Al-Hinai","doi":"10.1115/IMECE2020-23536","DOIUrl":"https://doi.org/10.1115/IMECE2020-23536","url":null,"abstract":"\u0000 Wood plastic composite materials have shown a remarkable performance in various applications due to its inherent properties like strength, durability, and lightweight over conventional composite materials. However, utilization of wood as an organic filler for polymers poses a serious negative impact to the green areas. Therefore, utilization of agro-residues as organic fillers instead of wood offers a sustainable solution to the aforementioned problem. In this context, this study aims to investigate the potential use of date palm pedicel agro-residues as natural fillers in eco-composites in which recycled post-consumer polypropylene is used as a matrix. Three levels of date palm flour content, namely, 10 v.%, 20 v.% and 30 v.% are used. The influence of the date palm pedicels flour content on the mechanical, physical and thermal behavior of the developed eco-composites is examined. Material properties of the fabricated eco-composites are characterized experimentally according to ASTM standards. Thermogravimetric analysis (TGA) is also performed to assess the thermal decomposition of the developed composites. Moreover, the morphology of fractured regions is captured using Scanning Electron Microscope (SEM). Generally, adding natural fillers to the polymer matrix is a cost effective option. However, it also slightly affects tensile strength, elongation, and flexural strength at break and enhance the Young’s modulus compared to the neat polypropylene. Interestingly, it is observed that the recycled polypropylene based composites are more repellent to water absorption in comparison to the virgin polypropylene-based composites. This attribute might be due to the surface quality transformation for the reprocessed plastic polymer.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"85 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79361290","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}
Seyed Hamid Reza Sanei, Hanna Drozynski, Dakota R Hetrick
The mechanical properties of polymers highly depend on the loading rate, however, the effect of loading/strain rate with the addition of Carbon Nanotube is not well understood. In this study, the effect of Carbon Nanotube (CNT) content on the rate dependence of polymers was studied. Injection molded mini-tensile samples with CNT content ranging from 0 to 15wt% at strain rates of .0006, .0013, .0019 and .0025 s−1 were tested. It was found that as strain rate increased, the ultimate strength and Young s Modulus of the tensile specimens increased. It was also shown that addition of CNT will lower the chain mobility of polymer and lower the polymer dependence of properties to strain rates.
{"title":"Effect of Strain Rate on Tensile Properties of Injection Molded Multiwall Carbon Nanotube Reinforced PA 6/6 Nanocomposites","authors":"Seyed Hamid Reza Sanei, Hanna Drozynski, Dakota R Hetrick","doi":"10.1115/IMECE2020-23049","DOIUrl":"https://doi.org/10.1115/IMECE2020-23049","url":null,"abstract":"\u0000 The mechanical properties of polymers highly depend on the loading rate, however, the effect of loading/strain rate with the addition of Carbon Nanotube is not well understood. In this study, the effect of Carbon Nanotube (CNT) content on the rate dependence of polymers was studied. Injection molded mini-tensile samples with CNT content ranging from 0 to 15wt% at strain rates of .0006, .0013, .0019 and .0025 s−1 were tested. It was found that as strain rate increased, the ultimate strength and Young s Modulus of the tensile specimens increased. It was also shown that addition of CNT will lower the chain mobility of polymer and lower the polymer dependence of properties to strain rates.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79652789","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}
Isaiah Yasko, A. Lutfullaeva, C. Fais, Muhammad Ali, K. Alam
Fixed-geometry hydrodynamic thrust bearings rely on convergent geometry on the bearing face in the direction of relative motion to develop and maintain hydrodynamic pressure. Machining the convergent taper feature onto the bearing using traditional manufacturing processes can prove to be a difficult process due to the small magnitude of taper depth necessary for proper bearing performance. The work presented here investigates three different types of carbon fibers (AS-4/IM7/T-300) in an epoxy (3501-6) matrix for composite lamina formulation in taper-land composite thrust bearings as a means of controlling taper depth via thermal expansion so that favorable bearing functionality is maintained during load fluctuation without the need for traditional machining processes to create the taper. Thermal expansion of specific composite laminate formulation is analyzed using the ABAQUS/CAE composite module. The thermo-mechanical analysis shows that under realistic in-service temperature conditions resulting from bearing friction-torque, the thermal expansion of composite tapered-land thrust bearings expand to provide physical surface gradient magnitudes of 0.09504 mm, 0.08987 mm and 0.08829 mm that are capable of producing hydrodynamic pressure.
{"title":"Thermal Expansion Simulation of Composite Hydrodynamic Thrust Bearings","authors":"Isaiah Yasko, A. Lutfullaeva, C. Fais, Muhammad Ali, K. Alam","doi":"10.1115/IMECE2020-23898","DOIUrl":"https://doi.org/10.1115/IMECE2020-23898","url":null,"abstract":"\u0000 Fixed-geometry hydrodynamic thrust bearings rely on convergent geometry on the bearing face in the direction of relative motion to develop and maintain hydrodynamic pressure. Machining the convergent taper feature onto the bearing using traditional manufacturing processes can prove to be a difficult process due to the small magnitude of taper depth necessary for proper bearing performance. The work presented here investigates three different types of carbon fibers (AS-4/IM7/T-300) in an epoxy (3501-6) matrix for composite lamina formulation in taper-land composite thrust bearings as a means of controlling taper depth via thermal expansion so that favorable bearing functionality is maintained during load fluctuation without the need for traditional machining processes to create the taper. Thermal expansion of specific composite laminate formulation is analyzed using the ABAQUS/CAE composite module. The thermo-mechanical analysis shows that under realistic in-service temperature conditions resulting from bearing friction-torque, the thermal expansion of composite tapered-land thrust bearings expand to provide physical surface gradient magnitudes of 0.09504 mm, 0.08987 mm and 0.08829 mm that are capable of producing hydrodynamic pressure.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77939180","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. Micheal, Y. Bahei-El-din, Mahmoud E. Abd El-Latief
When inevitable, failure in composite laminates is preferred to occur gracefully to avoid loss of property and possibly life. While the inherent inhomogeneity leads to slow dissipation of damage-related energy, overall failure is fiber-dominated and occurs in a rather brittle manner. Multidirectional plies usually give a more ductile response. Additionally, stiffness and strength as well as cost are important factors to consider in designing composite laminates. It is hence desirable to optimize for high mechanical properties and low cost while keeping graceful failure. Designing composite laminates with hybrid systems and layups, which permit gradual damage energy dissipation, are two ways proposed in this work to optimize for mechanical properties while avoiding catastrophic failure. In the hybrid system design, combining the less expensive glass reinforced plies with carbon reinforced plies offers a cost-effective product, marginal mechanical properties change and ductile profile upon failure. Hybrid glass/carbon composite laminates subjected to three-point bending showed strain to failure which is double that measured for carbon composite specimens, without affecting the ultimate load. Energy dissipation mechanisms were also created by building laminates which were intentionally made discontinuous by introducing cuts in the fibers of the interior plies. This created a longer path for damage before cutting through the next ply resulting in double failure strain with marginal reduction in load. The effect of fiber discontinuity in terms of spacing and distribution are among the factors considered.
{"title":"Designing Composites for Graceful Failure","authors":"A. Micheal, Y. Bahei-El-din, Mahmoud E. Abd El-Latief","doi":"10.1115/IMECE2020-23039","DOIUrl":"https://doi.org/10.1115/IMECE2020-23039","url":null,"abstract":"\u0000 When inevitable, failure in composite laminates is preferred to occur gracefully to avoid loss of property and possibly life. While the inherent inhomogeneity leads to slow dissipation of damage-related energy, overall failure is fiber-dominated and occurs in a rather brittle manner. Multidirectional plies usually give a more ductile response. Additionally, stiffness and strength as well as cost are important factors to consider in designing composite laminates. It is hence desirable to optimize for high mechanical properties and low cost while keeping graceful failure.\u0000 Designing composite laminates with hybrid systems and layups, which permit gradual damage energy dissipation, are two ways proposed in this work to optimize for mechanical properties while avoiding catastrophic failure. In the hybrid system design, combining the less expensive glass reinforced plies with carbon reinforced plies offers a cost-effective product, marginal mechanical properties change and ductile profile upon failure. Hybrid glass/carbon composite laminates subjected to three-point bending showed strain to failure which is double that measured for carbon composite specimens, without affecting the ultimate load.\u0000 Energy dissipation mechanisms were also created by building laminates which were intentionally made discontinuous by introducing cuts in the fibers of the interior plies. This created a longer path for damage before cutting through the next ply resulting in double failure strain with marginal reduction in load. The effect of fiber discontinuity in terms of spacing and distribution are among the factors considered.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88215328","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}
Understanding the effect of load sequence is important in the context of a blade-disc dovetail joint in an aero-engine and many other such applications where, the mating surfaces undergo fretting wear under variable slip amplitude loading conditions. In the present work, a two-dimensional finite element analysis is carried out for a cylinder-on-plate configuration. The cylinder is modeled as deformable whereas the plate is modelled as rigid. An incremental wear modelling algorithm is used to model the wear of cylindrical pad while the plate is assumed as un-worn. This simulates a practical scenario where, generally one of the mating surfaces is sufficiently hardened or an interfacial harder/sacrificial element is inserted to restrict the wear to only one of the surfaces. A Fortran-based ABAQUS® subroutine UMESHMOTION is used to simulate the wear profile for the cylinder. A constant extrapolation technique is used to simulate 18000 cycles of fretting. The finite element analysis results are validated with the analytical solutions and literature data. The fretting wear modelling is carried out for two different slip amplitudes viz., 25 μm and 150 μm, to simulate the low and high slip amplitude loading respectively. Two blocks of alternate low and high slip amplitudes are applied to understand the influence of load sequence. Important contact parameters viz., contact pressure, contact stresses and contact slip are extracted. A comparison is made between the low-high and high-low load sequence based on the contact tractions and worn out profiles.
{"title":"Finite Element Study of the Effect of Load Sequence on the Fretting Wear","authors":"Pankaj Dhaka, R. Prakash","doi":"10.1115/IMECE2020-23275","DOIUrl":"https://doi.org/10.1115/IMECE2020-23275","url":null,"abstract":"\u0000 Understanding the effect of load sequence is important in the context of a blade-disc dovetail joint in an aero-engine and many other such applications where, the mating surfaces undergo fretting wear under variable slip amplitude loading conditions. In the present work, a two-dimensional finite element analysis is carried out for a cylinder-on-plate configuration. The cylinder is modeled as deformable whereas the plate is modelled as rigid. An incremental wear modelling algorithm is used to model the wear of cylindrical pad while the plate is assumed as un-worn. This simulates a practical scenario where, generally one of the mating surfaces is sufficiently hardened or an interfacial harder/sacrificial element is inserted to restrict the wear to only one of the surfaces. A Fortran-based ABAQUS® subroutine UMESHMOTION is used to simulate the wear profile for the cylinder. A constant extrapolation technique is used to simulate 18000 cycles of fretting. The finite element analysis results are validated with the analytical solutions and literature data. The fretting wear modelling is carried out for two different slip amplitudes viz., 25 μm and 150 μm, to simulate the low and high slip amplitude loading respectively. Two blocks of alternate low and high slip amplitudes are applied to understand the influence of load sequence. Important contact parameters viz., contact pressure, contact stresses and contact slip are extracted. A comparison is made between the low-high and high-low load sequence based on the contact tractions and worn out profiles.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77360359","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}
Offshore wind turbines are considered as a reliable source of electricity generation. However, due to the large cost of the construction and installation of offshore wind turbines, most wind turbines are designed to operate for more than 20 years. One of the biggest issues which causes a severe damage to the construction of wind turbines is the existence of a very corrosive environment including large mechanical loads applied to the construction by the waves and the high concentration of salt and other chemicals in the sea water. The construction of offshore wind turbine can be divided into four main regions based on the types of exposure to the water and the corrosive environment, including submerged zone, tidal zone, splash zone, and atmospheric zone. In this study, experiments were conducted to compare the impact of impingement flow of 3.5 w.t.% NaCl solution on the epoxy coating samples to the exposure of the same type of samples to a stationary 3.5 w.t.% NaCl solution. Those two exposure conditions correspond to the environments at the top and the bottom part of the submerged zone of offshore wind turbines respectively. Electrochemical Impedance Spectroscopy (EIS) method was used to monitor the degradation of organic coatings. The surface roughness was measured by Atomic Force Microscope (AFM). The roughness of the coated surfaces before and after the exposure was compared. For the two different flow conditions, i.e. impingement flow and stationary immersion, significant differences have been discovered from the EIS results and AFM results. We observed a more severe degradation in the epoxy coatings in impingement flow, and a rougher surface is formed for coating samples subjected to impingement flow.
{"title":"Comparison of Epoxy Coating Degradations Under Impingement Flow and Stationary Immersion","authors":"Amin Vedadi, M. Parvej, Xinnan Wang, Yechun Wang","doi":"10.1115/IMECE2020-24274","DOIUrl":"https://doi.org/10.1115/IMECE2020-24274","url":null,"abstract":"\u0000 Offshore wind turbines are considered as a reliable source of electricity generation. However, due to the large cost of the construction and installation of offshore wind turbines, most wind turbines are designed to operate for more than 20 years. One of the biggest issues which causes a severe damage to the construction of wind turbines is the existence of a very corrosive environment including large mechanical loads applied to the construction by the waves and the high concentration of salt and other chemicals in the sea water. The construction of offshore wind turbine can be divided into four main regions based on the types of exposure to the water and the corrosive environment, including submerged zone, tidal zone, splash zone, and atmospheric zone. In this study, experiments were conducted to compare the impact of impingement flow of 3.5 w.t.% NaCl solution on the epoxy coating samples to the exposure of the same type of samples to a stationary 3.5 w.t.% NaCl solution. Those two exposure conditions correspond to the environments at the top and the bottom part of the submerged zone of offshore wind turbines respectively. Electrochemical Impedance Spectroscopy (EIS) method was used to monitor the degradation of organic coatings. The surface roughness was measured by Atomic Force Microscope (AFM). The roughness of the coated surfaces before and after the exposure was compared. For the two different flow conditions, i.e. impingement flow and stationary immersion, significant differences have been discovered from the EIS results and AFM results. We observed a more severe degradation in the epoxy coatings in impingement flow, and a rougher surface is formed for coating samples subjected to impingement flow.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74446176","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}
Thermoelectric materials are defined as materials which can convert heat into electrical energy. Thermoelectric materials are often used for applications such as power generation or refrigeration. Because of the applications for thermoelectric materials, it is important to understand the electrical-to-thermal coupling behavior of such materials. The thermoelectric materials simulated are 2D film configurations of Tin Selenide (SnSe). Using the derivations for non-equilibrium electron-phonon dynamics as well as obtaining the phonon dispersions, second-order and third-order elastic constants, the thermoelectric properties can be calculated. For the purposes of this paper, the correlation of thermoelectric properties such as thermopwer, thermal conductivitty, and thermoelectric figure of merit with parameters such as the characteristic length of the 2D material as well as the applied voltages of 0 V/m, 10,000 V/m, and 20,000 V/m over the 2D material. Furthermore, an analysis on the effect of strain on the thermoelectric properties of SnSe is conducted.
{"title":"Calculation and Variation of Thermoelectric Properties of Phase Transition Materials","authors":"Micah P. Vallin, Richard Z. Zhang","doi":"10.1115/IMECE2020-24597","DOIUrl":"https://doi.org/10.1115/IMECE2020-24597","url":null,"abstract":"\u0000 Thermoelectric materials are defined as materials which can convert heat into electrical energy. Thermoelectric materials are often used for applications such as power generation or refrigeration. Because of the applications for thermoelectric materials, it is important to understand the electrical-to-thermal coupling behavior of such materials. The thermoelectric materials simulated are 2D film configurations of Tin Selenide (SnSe). Using the derivations for non-equilibrium electron-phonon dynamics as well as obtaining the phonon dispersions, second-order and third-order elastic constants, the thermoelectric properties can be calculated. For the purposes of this paper, the correlation of thermoelectric properties such as thermopwer, thermal conductivitty, and thermoelectric figure of merit with parameters such as the characteristic length of the 2D material as well as the applied voltages of 0 V/m, 10,000 V/m, and 20,000 V/m over the 2D material. Furthermore, an analysis on the effect of strain on the thermoelectric properties of SnSe is conducted.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"2015 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74022815","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 electrochemical-mechanical modeling of solid-state batteries, there is a lack of understanding of the mechanical parameters and mode of deformation of lithium metal. Understanding these characteristics is crucial for predicting the propagation of lithium dendrites through the electrolyte — a key element of battery safety. Past theories have assumed linear elastic as well as elastic-plastic deformation of lithium. However, recent experiments show that the primary mode of deformation is creep. This study replicates the temperature dependent mechanical experiments but inside an industrial dry room, where battery cells are manufactured at high volume. Furthermore, this work conducts time dependent studies — also inside the dry room — to gain insight of the large deformation theories of lithium metal. The results confirm the activation energy, which dictates the creep mechanism, is correlated to core diffusion rather than lattice diffusion.
{"title":"Elastic-Viscoplastic Mechanics of Lithium in a Standard Dry Room","authors":"Lara L. Dienemann, A. Saigal, M. Zimmerman","doi":"10.1115/IMECE2020-23894","DOIUrl":"https://doi.org/10.1115/IMECE2020-23894","url":null,"abstract":"In electrochemical-mechanical modeling of solid-state batteries, there is a lack of understanding of the mechanical parameters and mode of deformation of lithium metal. Understanding these characteristics is crucial for predicting the propagation of lithium dendrites through the electrolyte — a key element of battery safety. Past theories have assumed linear elastic as well as elastic-plastic deformation of lithium. However, recent experiments show that the primary mode of deformation is creep. This study replicates the temperature dependent mechanical experiments but inside an industrial dry room, where battery cells are manufactured at high volume. Furthermore, this work conducts time dependent studies — also inside the dry room — to gain insight of the large deformation theories of lithium metal. The results confirm the activation energy, which dictates the creep mechanism, is correlated to core diffusion rather than lattice diffusion.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"150 5 Suppl 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91127208","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}
Even though silkworm are the most dominant type of silk fibers used for commercial applications, spider silk has a definitive role in biomedical applications due to its biocompatibility and excellent mechanical properties as biomaterials. In recent years, recombinant production of the silk proteins at a larger scale has found new interest. Spider silk composites with a combination of a variety of other biomaterials have also been used to improve properties such as bio-compatibility, mechanical strength and controlled degradation. [1] A major constituent of spider silk fibers, are spidroin proteins. These are made up of repetitive segments flanked by conserved non-repetitive domains. The fiber proteins consist of a light chain and a heavy chain that are connected via a single disulfide bond. [2] Present paper employed steered molecular dynamics (SMD) as the principal method of investigating the mechanical properties of these nanoscale spider silk protein 3LR2, with a residual count of 134 amino acids. [3]. SMD simulations were performed by pulling on β-chain of the protein in the x-direction, while holding the other fixed. The focus of this paper is to investigate the mechanical properties of the nanoscale spider silk proteins with lengths of about 4.5nm in a folded state, leading to understanding of their feasibility in bio-printing of a composite spider silk biomaterial with a blend of various other biomaterials such as collagen. An in-depth insight into the fraying and tensile deformation and structural properties of the spider silk proteins are of innovative significance for a multitude of biomedical engineering applications. A calculated Gibbs free energy value of 18.59 kCal/mol via umbrella sampling corresponds with a complete separation of a single chain from a spider silk protein in case of fraying. Force needed for complete separation of the chain from the spider silk protein is analyzed, and discussed in this paper. It is found that the protein molecule undergoes a tensile stretch at strain rates of ≅ 11.65. An elastic modulus of 20.136 GPa, calculated via simple SMD simulations by subjecting the silk β-chain to a tensile stretch is also presented.
{"title":"Mechanical Properties of Spider Silk for Use As a Biomaterial: Molecular Dynamics Investigations","authors":"A. Rawal, Kristen L Rhinehardt, R. Mohan","doi":"10.1115/IMECE2020-23951","DOIUrl":"https://doi.org/10.1115/IMECE2020-23951","url":null,"abstract":"\u0000 Even though silkworm are the most dominant type of silk fibers used for commercial applications, spider silk has a definitive role in biomedical applications due to its biocompatibility and excellent mechanical properties as biomaterials. In recent years, recombinant production of the silk proteins at a larger scale has found new interest. Spider silk composites with a combination of a variety of other biomaterials have also been used to improve properties such as bio-compatibility, mechanical strength and controlled degradation. [1] A major constituent of spider silk fibers, are spidroin proteins. These are made up of repetitive segments flanked by conserved non-repetitive domains. The fiber proteins consist of a light chain and a heavy chain that are connected via a single disulfide bond. [2] Present paper employed steered molecular dynamics (SMD) as the principal method of investigating the mechanical properties of these nanoscale spider silk protein 3LR2, with a residual count of 134 amino acids. [3]. SMD simulations were performed by pulling on β-chain of the protein in the x-direction, while holding the other fixed. The focus of this paper is to investigate the mechanical properties of the nanoscale spider silk proteins with lengths of about 4.5nm in a folded state, leading to understanding of their feasibility in bio-printing of a composite spider silk biomaterial with a blend of various other biomaterials such as collagen. An in-depth insight into the fraying and tensile deformation and structural properties of the spider silk proteins are of innovative significance for a multitude of biomedical engineering applications. A calculated Gibbs free energy value of 18.59 kCal/mol via umbrella sampling corresponds with a complete separation of a single chain from a spider silk protein in case of fraying. Force needed for complete separation of the chain from the spider silk protein is analyzed, and discussed in this paper. It is found that the protein molecule undergoes a tensile stretch at strain rates of ≅ 11.65. An elastic modulus of 20.136 GPa, calculated via simple SMD simulations by subjecting the silk β-chain to a tensile stretch is also presented.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75268583","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 well-known industrial standard called A36 alloy steel is an iron-based alloy that has many applications due to its ability to be easily machined and welded. The alloy has less than 0.3% carbon by weight and is therefore considered a low carbon alloy. Because of this low carbon content, the alloy is useful as a general-purpose steel. It is altogether strong, tough, ductile, weldable, and formable. It is used in the construction of bridges, buildings, automobiles, and heavy equipment as well as in the construction industry. A36 steel also contains small amounts of other elements including manganese, sulfur, phosphorus, and silicon. These elements are added to give the steel alloy desired mechanical and chemical properties. The A36 steel alloy gets the number 36 in its name because of its yield strength. The steel, in most to all configurations, will have a yield strength of a minimum of 36,000 pounds per square inch. This shows high ductility in the material. The physical characteristics and molecular structure of A36 steel are also well known. However, there is little known about the effect of high-velocity impact on the crystalline structure and material phase of this metal alloy. Sections of approximately 90 × 90 square microns were cut off the test samples, keeping with the required standards for surface finish. These surfaces were examined and analyzed after impact. The surface sections were selected from a range of areas including those immediately under the impact crater to locations not physically affected by the impact. Three different impact speeds were applied, and the prepared samples were examined. An EBSD (Electron Backscatter Diffraction) imaging microscope is used to examine the crystalline structure of the test sample post-impact. Most metals crystallize in one of three prevalent structures: body-centered cubic (BCC), hexagonal close-packed (HCP), or face-centered cubic (FCC). Since these crystalline structures are the most expected lattice formations, the samples are examined post impact for changes in the allocation of molecular structure. The results were then tabulated according to the regions relative to the impact crater. In previous research, results show that post-impact inspection of HCP phase change, in iron specifically, is completely and rapidly reversible during impact. However, in this study, traces of HCP were found at some locations in all stages of post-impact. This study also found that the BCC crystalline structure remained the dominant phase structure after impact. This is true with all test samples and all levels of shock loading.
{"title":"Crystalline Phase Change due to High Speed Impact on A36 Steel","authors":"Muna Y. Slewa","doi":"10.1115/IMECE2020-24394","DOIUrl":"https://doi.org/10.1115/IMECE2020-24394","url":null,"abstract":"\u0000 The well-known industrial standard called A36 alloy steel is an iron-based alloy that has many applications due to its ability to be easily machined and welded. The alloy has less than 0.3% carbon by weight and is therefore considered a low carbon alloy. Because of this low carbon content, the alloy is useful as a general-purpose steel. It is altogether strong, tough, ductile, weldable, and formable. It is used in the construction of bridges, buildings, automobiles, and heavy equipment as well as in the construction industry. A36 steel also contains small amounts of other elements including manganese, sulfur, phosphorus, and silicon. These elements are added to give the steel alloy desired mechanical and chemical properties. The A36 steel alloy gets the number 36 in its name because of its yield strength. The steel, in most to all configurations, will have a yield strength of a minimum of 36,000 pounds per square inch. This shows high ductility in the material.\u0000 The physical characteristics and molecular structure of A36 steel are also well known. However, there is little known about the effect of high-velocity impact on the crystalline structure and material phase of this metal alloy. Sections of approximately 90 × 90 square microns were cut off the test samples, keeping with the required standards for surface finish. These surfaces were examined and analyzed after impact. The surface sections were selected from a range of areas including those immediately under the impact crater to locations not physically affected by the impact. Three different impact speeds were applied, and the prepared samples were examined. An EBSD (Electron Backscatter Diffraction) imaging microscope is used to examine the crystalline structure of the test sample post-impact.\u0000 Most metals crystallize in one of three prevalent structures: body-centered cubic (BCC), hexagonal close-packed (HCP), or face-centered cubic (FCC). Since these crystalline structures are the most expected lattice formations, the samples are examined post impact for changes in the allocation of molecular structure. The results were then tabulated according to the regions relative to the impact crater. In previous research, results show that post-impact inspection of HCP phase change, in iron specifically, is completely and rapidly reversible during impact. However, in this study, traces of HCP were found at some locations in all stages of post-impact. This study also found that the BCC crystalline structure remained the dominant phase structure after impact. This is true with all test samples and all levels of shock loading.","PeriodicalId":23837,"journal":{"name":"Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications","volume":"53 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91441525","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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