S. Liu, Lifeng Wang, Jia-cheng Ge, Zhen-Duo Wu, Y. Ke, Qiang Li, B. Sun, T. Feng, Yuan Wu, J.T. Wang, H. Hahn, Yang Ren, J. Almer, Xun-li Wang, S. Lan
Abstract The multiscale structures in a Pd82Si18 binary bulk metallic glass before and after deformation were studied using electron microscopies, high-energy synchrotron X-ray diffraction, and small-angle scattering techniques. The experimental results revealed an enhancement of hierarchical structure heterogeneities on multiple length scales after deformation. Hierarchical multiple shear bands of high number density were observed after bending, introducing complex but periodically distributed residual strain. Pair distribution function analysis revealed that the connectivity of the short-range clusters on the medium-range scale determines the packing density difference between the tension side and the compression side in the sample after bending. In-situ synchrotron X-ray diffraction study also revealed a transformation of connection modes among short-range clusters under uniaxial tension and compression, which is consistent with those of triaxial tension/compression parts upon bending in Pd82Si18 glassy alloys. The nanoscale heterogeneities for metallic glasses after deformation observed by small-angle scattering and transmission electron microscopy may be attributed to the nanoscale amorphous phase separation and interacting multiple shear bands enhanced by plastic deformation. Our findings suggested that the enhancement of hierarchical heterogeneous structure on multiple length scales may explain the excellent plasticity of Pd-Si glassy alloys, deepening the understanding of structure-property relation during plastic deformation in metallic glasses.
{"title":"Deformation-Enhanced Hierarchical Multiscale Structure Heterogeneity in a Pd-Si Bulk Metallic Glass","authors":"S. Liu, Lifeng Wang, Jia-cheng Ge, Zhen-Duo Wu, Y. Ke, Qiang Li, B. Sun, T. Feng, Yuan Wu, J.T. Wang, H. Hahn, Yang Ren, J. Almer, Xun-li Wang, S. Lan","doi":"10.2139/ssrn.3525109","DOIUrl":"https://doi.org/10.2139/ssrn.3525109","url":null,"abstract":"Abstract The multiscale structures in a Pd82Si18 binary bulk metallic glass before and after deformation were studied using electron microscopies, high-energy synchrotron X-ray diffraction, and small-angle scattering techniques. The experimental results revealed an enhancement of hierarchical structure heterogeneities on multiple length scales after deformation. Hierarchical multiple shear bands of high number density were observed after bending, introducing complex but periodically distributed residual strain. Pair distribution function analysis revealed that the connectivity of the short-range clusters on the medium-range scale determines the packing density difference between the tension side and the compression side in the sample after bending. In-situ synchrotron X-ray diffraction study also revealed a transformation of connection modes among short-range clusters under uniaxial tension and compression, which is consistent with those of triaxial tension/compression parts upon bending in Pd82Si18 glassy alloys. The nanoscale heterogeneities for metallic glasses after deformation observed by small-angle scattering and transmission electron microscopy may be attributed to the nanoscale amorphous phase separation and interacting multiple shear bands enhanced by plastic deformation. Our findings suggested that the enhancement of hierarchical heterogeneous structure on multiple length scales may explain the excellent plasticity of Pd-Si glassy alloys, deepening the understanding of structure-property relation during plastic deformation in metallic glasses.","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81981104","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. K. Bardhan, Bikash Bhunia, Souvik Goswami, P. Chandra
Surface topography of the machined workpiece is one of the most important criterions for the analysis of the grinding process and also has a significant influence on the fatigue behaviour of workpiece. In the present work, the experiments are carried out for optimum surface roughness and rate of material removal with variables like feed rate, speed of table and depth of cut on stainless steel material AISI 304 with the Al2O3 abrasive grinding wheel. Taguchi optimization technique is applied to optimize the process parameters to get optimum results of surface finish during grinding. The most influencing process parameters are depth of cut and table speed to optimize the MRR and surface roughness. The results reveals that optimum values of process parameters are 0.5 mm feed rate, 16 m/min table speed and depth of cut 0.02 mm to achieve the optimum surface roughness.
{"title":"Optimization of Process Parameters of Surface Grinding of AISI 304 Steel with Al 2O 3 Abrasive Wheel","authors":"P. K. Bardhan, Bikash Bhunia, Souvik Goswami, P. Chandra","doi":"10.2139/ssrn.3526001","DOIUrl":"https://doi.org/10.2139/ssrn.3526001","url":null,"abstract":"Surface topography of the machined workpiece is one of the most important criterions for the analysis of the grinding process and also has a significant influence on the fatigue behaviour of workpiece. In the present work, the experiments are carried out for optimum surface roughness and rate of material removal with variables like feed rate, speed of table and depth of cut on stainless steel material AISI 304 with the Al2O3 abrasive grinding wheel. Taguchi optimization technique is applied to optimize the process parameters to get optimum results of surface finish during grinding. The most influencing process parameters are depth of cut and table speed to optimize the MRR and surface roughness. The results reveals that optimum values of process parameters are 0.5 mm feed rate, 16 m/min table speed and depth of cut 0.02 mm to achieve the optimum surface roughness.","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78756417","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 submerged arc welding process is most widely used arc welding process for joining thick plates and pipes. The features that distinguishing submerged arc welding from other arc welding process is gradually fusible material termed as flux. The flux used in submerged arc welding contributes a major part (above 50%) towards the total welding cost. The properties of weld metal have been found to be dependent upon flux-electrode-base metal-composition on welding parameters. Flux and filler metal play a central role in ascertaining property of weld metal. In the present work, the effect of operating arc voltage, welding current, welding speed and nozzle distance on flux consumption and chemical composition of carbon and silicon has been studied. Mathematical model was developed from data generated using two level half factorial technique. The experiment is conducted as per the design matrix. Design Expert software 7 is used in order to (i) the designing of a set of experiments for adequate and reliable measurement of the true mean response of interest (ii) the determining of mathematical model with best fits (iii) finding the optimum set of experimental factors that produces maximum or minimum value of response and (iv) representing the direct effects of procedure variables on the flux utilization, current and silicon through two dimensional graphs. It was observed that the flux consumption decrease with increase in wire feed rate and its welding speed. The flux utilization increase with increase in arc voltage. The effect of constant tip to work distance has in significant effect on flux utilization. Carbon percentage increase with increase in arc voltage and welding speed. Carbon proportion decrease with increase in welding current. Silicon percentage decrease as increase in current and voltage.
{"title":"Effect of Welding Parameter of Flux Consumption in Submerged Arc Welding","authors":"S. Thakur, G. Goga, Avtar Singh","doi":"10.2139/ssrn.3572588","DOIUrl":"https://doi.org/10.2139/ssrn.3572588","url":null,"abstract":"The submerged arc welding process is most widely used arc welding process for joining thick plates and pipes. The features that distinguishing submerged arc welding from other arc welding process is gradually fusible material termed as flux. The flux used in submerged arc welding contributes a major part (above 50%) towards the total welding cost. The properties of weld metal have been found to be dependent upon flux-electrode-base metal-composition on welding parameters. Flux and filler metal play a central role in ascertaining property of weld metal. In the present work, the effect of operating arc voltage, welding current, welding speed and nozzle distance on flux consumption and chemical composition of carbon and silicon has been studied. Mathematical model was developed from data generated using two level half factorial technique. The experiment is conducted as per the design matrix. Design Expert software 7 is used in order to (i) the designing of a set of experiments for adequate and reliable measurement of the true mean response of interest (ii) the determining of mathematical model with best fits (iii) finding the optimum set of experimental factors that produces maximum or minimum value of response and (iv) representing the direct effects of procedure variables on the flux utilization, current and silicon through two dimensional graphs. It was observed that the flux consumption decrease with increase in wire feed rate and its welding speed. The flux utilization increase with increase in arc voltage. The effect of constant tip to work distance has in significant effect on flux utilization. Carbon percentage increase with increase in arc voltage and welding speed. Carbon proportion decrease with increase in welding current. Silicon percentage decrease as increase in current and voltage.","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84800740","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}
Submerged arc welding is generally used for fabrication large diameters line pipes, pressure vessels and wind turbines due to its high deposition rates, high-quality welds, ease of automation and low operation skills necessities. Submerged arc welding is characterized by a large number of process parameters influencing the performance of the output such as hardness two level and bead geometry, which subsequently affects the weld quality. In this research work, the effect of different welding parameters on drop geometry has been investigated. Four welding parameters specifically current, arc voltage, welding travel speed and nozzle-to-plate distance are selected. Mathematically model was developed from the data generated using two-level half factoring. The design expert 7 is implemented in order to find out significant and communication effect. It has been observed that width of the bead, penetration, reinforcement is an an increased with an an increase in welding current. The width of bead also an increases with an an increase in voltage but reinforcement and penetration decrease with an an increase in voltage. Nozzle to plate distance and welding speed produces very fewer effect on width of bead, penetration, and reinforcement.
{"title":"Influence of Welding Parameter on Bead Geometry of Weld Metal in Submerged Arc Welding","authors":"S. Thakur, G. Goga, Avtar Singh","doi":"10.2139/ssrn.3635987","DOIUrl":"https://doi.org/10.2139/ssrn.3635987","url":null,"abstract":"Submerged arc welding is generally used for fabrication large diameters line pipes, pressure vessels and wind turbines due to its high deposition rates, high-quality welds, ease of automation and low operation skills necessities. Submerged arc welding is characterized by a large number of process parameters influencing the performance of the output such as hardness two level and bead geometry, which subsequently affects the weld quality. In this research work, the effect of different welding parameters on drop geometry has been investigated. Four welding parameters specifically current, arc voltage, welding travel speed and nozzle-to-plate distance are selected. Mathematically model was developed from the data generated using two-level half factoring. The design expert 7 is implemented in order to find out significant and communication effect. It has been observed that width of the bead, penetration, reinforcement is an an increased with an an increase in welding current. The width of bead also an increases with an an increase in voltage but reinforcement and penetration decrease with an an increase in voltage. Nozzle to plate distance and welding speed produces very fewer effect on width of bead, penetration, and reinforcement.","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86967484","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 S-type load cell was installed below the front axle of a 2WD tractor to record the dynamic load of the front axle. The load was recorded with the help of a data logger (DT800). Theoretical and actual speeds of the tractor were measured with proximity sensor and non-contact type radar sensor, respectively to calculate the wheel slip. The test was conducted on two types of road surfaces namely tarmacadam surface with slopes of 0°, 3.4° & 4.8° and unpaved surfaces with slopes of 0°, 2.86° and 5.61° with payload of 2, 2.5 and 3 tons on trailer at hitch heights of 45, 55 and 60 cm above the ground. It was observed that dynamic load on the front axle and slip decreases from 603 kg to 438 kg and 8.65 to 5.49 %, respectively on raising the hitch height from 45 cm to 60 cm above the ground at a payload of 2 tons on the trailer. Similar results were obtained on all payloads at different slopes and road surfaces. Lowering the hitch height resulted in the reduction of weight transfer from the front to the rear axle from 32 to 7 % of the static weight of the front axle thereby improving the stability of the tractor.
{"title":"Effect of Hitch Height on Wheel Slip and Stability of 2WD Tractor","authors":"B. Chhetry, T. Tapang, P. K. Pranav","doi":"10.2139/ssrn.3516764","DOIUrl":"https://doi.org/10.2139/ssrn.3516764","url":null,"abstract":"A S-type load cell was installed below the front axle of a 2WD tractor to record the dynamic load of the front axle. The load was recorded with the help of a data logger (DT800). Theoretical and actual speeds of the tractor were measured with proximity sensor and non-contact type radar sensor, respectively to calculate the wheel slip. The test was conducted on two types of road surfaces namely tarmacadam surface with slopes of 0°, 3.4° & 4.8° and unpaved surfaces with slopes of 0°, 2.86° and 5.61° with payload of 2, 2.5 and 3 tons on trailer at hitch heights of 45, 55 and 60 cm above the ground. It was observed that dynamic load on the front axle and slip decreases from 603 kg to 438 kg and 8.65 to 5.49 %, respectively on raising the hitch height from 45 cm to 60 cm above the ground at a payload of 2 tons on the trailer. Similar results were obtained on all payloads at different slopes and road surfaces. Lowering the hitch height resulted in the reduction of weight transfer from the front to the rear axle from 32 to 7 % of the static weight of the front axle thereby improving the stability of the tractor.","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84557247","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}
T. Ali, L. Wang, Xingwang Cheng, Yangwei Wang, H. Cheng, Binbin Zhang, Anjin Liu, Xuefeng Xu, Zhenlu Zhou, Zixuan Ning, Ziqi Xu, Xinhua Min
Most of structural alloys' applications are under static, dynamic and cyclic forms of loading, for which Ti-5553 alloy in beta phase field is being investigated to confirm the mechanism of deformation and phase transformation upon quasi-static and dynamic compression. To achieve the fully beta phase field, Ti-5553 alloy was heated at 900oC (almost 50oC above beta tarsus temp.) for one hour of soaking time followed by air quenching. Thereafter, Dynamic compression (DC) by Split Hopkinson Pressure Bar (SHPB) and Quasi-static compression (QSC) were performed at strain rate of 103/s and 10-3/s, respectively. Recovered specimens were thoroughly examined by using different tools such as OM, SEM, HRTEM, EBSD to get reliable data for justification of logical conclusions. It's found that the prominent mode of deformation was dislocation slips along with twining to some extent in both of QSC and DC but sliding and spalling of grain boundary was more noticeable in former. Transformation of phases occurred in saturated dislocation slips grains in which from beta (BCC) to omega transformation has been completed by mechanical form of driving force in a way when set of two adjacent (110)ᵦ planes covered ±1/6 of total separation distance between two next to each other (111)ᵦ planes, equal but opposite shears, in (111)ᵦ direction and it could be justified by the 3% shrinkage of two closely existed (110)ᵦ planes after transformation to omega. Furthermore, it is noticed that the omega phase and alpha transformation occurred in the grains which were saturated with dislocation slips.
{"title":"Mechanical (Compressive) Form of Driving Force Triggered the Phase Transformation from Beta to Omega & Alpha Phases by Means of Dislocation Slips in Metastable Beta Phase Field Ti-5553 Alloy","authors":"T. Ali, L. Wang, Xingwang Cheng, Yangwei Wang, H. Cheng, Binbin Zhang, Anjin Liu, Xuefeng Xu, Zhenlu Zhou, Zixuan Ning, Ziqi Xu, Xinhua Min","doi":"10.2139/ssrn.3509324","DOIUrl":"https://doi.org/10.2139/ssrn.3509324","url":null,"abstract":"Most of structural alloys' applications are under static, dynamic and cyclic forms of loading, for which Ti-5553 alloy in beta phase field is being investigated to confirm the mechanism of deformation and phase transformation upon quasi-static and dynamic compression. To achieve the fully beta phase field, Ti-5553 alloy was heated at 900oC (almost 50oC above beta tarsus temp.) for one hour of soaking time followed by air quenching. Thereafter, Dynamic compression (DC) by Split Hopkinson Pressure Bar (SHPB) and Quasi-static compression (QSC) were performed at strain rate of 103/s and 10-3/s, respectively. Recovered specimens were thoroughly examined by using different tools such as OM, SEM, HRTEM, EBSD to get reliable data for justification of logical conclusions. It's found that the prominent mode of deformation was dislocation slips along with twining to some extent in both of QSC and DC but sliding and spalling of grain boundary was more noticeable in former. Transformation of phases occurred in saturated dislocation slips grains in which from beta (BCC) to omega transformation has been completed by mechanical form of driving force in a way when set of two adjacent (110)ᵦ planes covered ±1/6 of total separation distance between two next to each other (111)ᵦ planes, equal but opposite shears, in (111)ᵦ direction and it could be justified by the 3% shrinkage of two closely existed (110)ᵦ planes after transformation to omega. Furthermore, it is noticed that the omega phase and alpha transformation occurred in the grains which were saturated with dislocation slips.","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77007679","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}
Ai Shigang, Song Weili, Chen Yanfei, J. Reddy, F. Daining
In this study, the construction and examination of meso-structural finite element models of a Chemical-Vapor-Infiltrated (CVI) C/SiC composite is carried out based on X-ray microtomography digital images (i.e. image-based finite element method: IB-FEM). The accurate meso-structural features of the C/SiC composites, which are consisted of carbon fiber tows and CVI-SiC matrix, in particularly the cavity defects, are reconstructed in the meso-structural models. With the IB-FEM, the damage evolution and fracture behaviors of the C/SiC composite are investigated using the Abaqus standard program. Influences of the meso-structures on deformation, damage evolution, and fracture features of the C/SiC textile composite are studied, and they are compared with the results from a perfect RVE model. At the same time, an in situ tensile test is applied to the C/SiC composite under a CT real-time quantitative imaging system, aiming to investigate the damage and failure features of the material as well as to verify the IB-FEM. The IB-FEM results indicate that material damages initially occur at the defects, followed by propagating toward the fiber-tow/SiC-matrix interfaces with increasing load. Ultimately, the damages would be combined into marco-cracks, which is in good agreement with the in situ CT experiment results.
{"title":"Stress Field and Damage Evolution in C/SiC Woven Composites: Image-Based Finite Element Analysis and in situ X-Ray Computed Tomography Tests","authors":"Ai Shigang, Song Weili, Chen Yanfei, J. Reddy, F. Daining","doi":"10.2139/ssrn.3655866","DOIUrl":"https://doi.org/10.2139/ssrn.3655866","url":null,"abstract":"In this study, the construction and examination of meso-structural finite element models of a Chemical-Vapor-Infiltrated (CVI) C/SiC composite is carried out based on X-ray microtomography digital images (i.e. image-based finite element method: IB-FEM). The accurate meso-structural features of the C/SiC composites, which are consisted of carbon fiber tows and CVI-SiC matrix, in particularly the cavity defects, are reconstructed in the meso-structural models. With the IB-FEM, the damage evolution and fracture behaviors of the C/SiC composite are investigated using the Abaqus standard program. Influences of the meso-structures on deformation, damage evolution, and fracture features of the C/SiC textile composite are studied, and they are compared with the results from a perfect RVE model. At the same time, an in situ tensile test is applied to the C/SiC composite under a CT real-time quantitative imaging system, aiming to investigate the damage and failure features of the material as well as to verify the IB-FEM. The IB-FEM results indicate that material damages initially occur at the defects, followed by propagating toward the fiber-tow/SiC-matrix interfaces with increasing load. Ultimately, the damages would be combined into marco-cracks, which is in good agreement with the in situ CT experiment results.","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77374736","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}
Rudraswamy M P, Dr.B.R. Patagundi, Dr. K. B. Prakash
In the present paper, effects of shrinkage in fiber reinforced concrete are studied. Here, in the current research work, an attempt is made to study the effects on shrinkage of concrete when five different fiber materials are used for reinforcing plain concrete. Three configurations of each reinforcing fiber material is studied. Fiber aspect ratios of 40 and 100 and a combination of the fibers of the two aspect ratios in equal proportion (hybrid) make up the three configurations for one individual fiber material reinforcement. Shrinkage values are indicated in terms of total length of crack and the total area of the crack. On-field measurement of crack dimensions at periodic time intervals ranging from 0 minutes to 28 days after casting of concrete has been undertaken to determine the accurate values of shrinkage cracks in the fifteen scenarios i.e. five reinforcing fiber materials with three configurations each using aspect ratio of fibers 40, 100 and the hybrid (40 +100) case. It is seen that, irrespective of the material of fiber used for reinforcing concrete, hybridized concrete consistently shows better results relative to single aspect ratio fiber reinforcement. This research also aims to provide a bench mark for future research works on shrinkage characteristics of hybridized fiber reinforced concrete
{"title":"An Investigation on the Shrinkage Characteristics of Hybrid Fiber Reinforced Concrete Produced by Using Fibers of Different Aspect Ratio","authors":"Rudraswamy M P, Dr.B.R. Patagundi, Dr. K. B. Prakash","doi":"10.31224/osf.io/dxrq9","DOIUrl":"https://doi.org/10.31224/osf.io/dxrq9","url":null,"abstract":"In the present paper, effects of shrinkage in fiber reinforced concrete are studied. Here, in the current research work, an attempt is made to study the effects on shrinkage of concrete when five different fiber materials are used for reinforcing plain concrete. Three configurations of each reinforcing fiber material is studied. Fiber aspect ratios of 40 and 100 and a combination of the fibers of the two aspect ratios in equal proportion (hybrid) make up the three configurations for one individual fiber material reinforcement. Shrinkage values are indicated in terms of total length of crack and the total area of the crack. On-field measurement of crack dimensions at periodic time intervals ranging from 0 minutes to 28 days after casting of concrete has been undertaken to determine the accurate values of shrinkage cracks in the fifteen scenarios i.e. five reinforcing fiber materials with three configurations each using aspect ratio of fibers 40, 100 and the hybrid (40 +100) case. It is seen that, irrespective of the material of fiber used for reinforcing concrete, hybridized concrete consistently shows better results relative to single aspect ratio fiber reinforcement. This research also aims to provide a bench mark for future research works on shrinkage characteristics of hybridized fiber reinforced concrete","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75546239","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}
L. Schwenk-Nebbe, M. Victoria, G. Andresen, M. Greiner
Anthropogenic climate change confronts our electricity systems with new challenges which require us to rethink fundamental concepts of collaboration. Strong benefits and synergies arise when intertwining electricity systems and grids across borders. Countries can both collaborate by extending interconnection capacities, varying their degree of self-sufficiency and by trading emission certificates, or equivalently attributing the burden of emission reductions in different ways among one another. We investigate a near future European electricity system in a brownfield approach. The primary source of emission neutral electricity is coming from different variable renewable energy sources, but it also includes current and planned nuclear, coal, lignite and gas fuelled power plants. We show that different CO2 emission attributions have an immense effect on the required local CO2 prices. Furthermore, we investigate how this influences the technology mix in the individual countries. Prominent economists argue that it may be conceivably simpler to get everyone on board of the energy transition if a common emission price is negotiated. A cost optimal allocation of emissions, represented by a single European carbon price, leads to the placement of the majority of carbon-emitting production capacity in a band through central Europe, and thus to hugely uneven carbon emissions, because the emitting generation is removed from many countries and relocated to a few. We conclude that it is significantly easier for certain countries to decarbonise their electricity production than for others. The difficulty in the specific country depends strongly on how emission allowances are allocated in Europe. A deep collaboration between the countries leads both to a lowered total system cost and, perhaps even more importantly, to CO2 emissions and required CO2 prices that are much more equal between the European partners.
{"title":"CO 2 Quota Attribution Effects on the European Electricity System Comprised of Self-Centred Actors","authors":"L. Schwenk-Nebbe, M. Victoria, G. Andresen, M. Greiner","doi":"10.2139/ssrn.3689207","DOIUrl":"https://doi.org/10.2139/ssrn.3689207","url":null,"abstract":"Anthropogenic climate change confronts our electricity systems with new challenges which require us to rethink fundamental concepts of collaboration. Strong benefits and synergies arise when intertwining electricity systems and grids across borders. Countries can both collaborate by extending interconnection capacities, varying their degree of self-sufficiency and by trading emission certificates, or equivalently attributing the burden of emission reductions in different ways among one another. We investigate a near future European electricity system in a brownfield approach. The primary source of emission neutral electricity is coming from different variable renewable energy sources, but it also includes current and planned nuclear, coal, lignite and gas fuelled power plants. We show that different CO<sub>2</sub> emission attributions have an immense effect on the required local CO<sub>2</sub> prices. Furthermore, we investigate how this influences the technology mix in the individual countries. Prominent economists argue that it may be conceivably simpler to get everyone on board of the energy transition if a common emission price is negotiated. A cost optimal allocation of emissions, represented by a single European carbon price, leads to the placement of the majority of carbon-emitting production capacity in a band through central Europe, and thus to hugely uneven carbon emissions, because the emitting generation is removed from many countries and relocated to a few. We conclude that it is significantly easier for certain countries to decarbonise their electricity production than for others. The difficulty in the specific country depends strongly on how emission allowances are allocated in Europe. A deep collaboration between the countries leads both to a lowered total system cost and, perhaps even more importantly, to CO<sub>2</sub> emissions and required CO<sub>2</sub> prices that are much more equal between the European partners.","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74946134","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}
Gradient high entropy alloys have attained great attention due to their exceptional mechanical properties. Here, molecular dynamic simulations are reported to introduce CoNiCrFeMn high entropy alloy with gradient structure and understand the relation between structural gradient and mechanical performance. The effect of gradient structure on the mechanical properties was studied by characterizing the structural evolution and dislocation substructures during tension loading. The gradient distributions of deformation faults and dislocations from the surface to the center of samples were explored in detail. Quantitative analysis shows that simultaneous improvement of ductility and strength is afford by high densities of dislocations in the grain interior. Moreover, the results revealed that the energy barrier for nucleation of deformation faults in the deformed layer of gradient high entropy alloy is higher than in uniform sample. The high strength and work hardening of gradient high entropy alloy attributed to the geometrically necessary dislocations distributed in grain interiors and having a form of bundles of concentrated dislocations. Based on the simulation results, the synergy between high strength and high ductility in high entropy alloys can be achieved through the gradient structure. The present study gives a method to better understanding the deformation mechanisms and mechanical properties of high entropy alloys with gradient structure.
{"title":"Understanding the Atomic-Scale Deformation in CoNiCrFeMn Nanocrystalline High Entropy Alloy with Gradient Structure","authors":"R. Mohammadzadeh","doi":"10.2139/ssrn.3678843","DOIUrl":"https://doi.org/10.2139/ssrn.3678843","url":null,"abstract":"Gradient high entropy alloys have attained great attention due to their exceptional mechanical properties. Here, molecular dynamic simulations are reported to introduce CoNiCrFeMn high entropy alloy with gradient structure and understand the relation between structural gradient and mechanical performance. The effect of gradient structure on the mechanical properties was studied by characterizing the structural evolution and dislocation substructures during tension loading. The gradient distributions of deformation faults and dislocations from the surface to the center of samples were explored in detail. Quantitative analysis shows that simultaneous improvement of ductility and strength is afford by high densities of dislocations in the grain interior. Moreover, the results revealed that the energy barrier for nucleation of deformation faults in the deformed layer of gradient high entropy alloy is higher than in uniform sample. The high strength and work hardening of gradient high entropy alloy attributed to the geometrically necessary dislocations distributed in grain interiors and having a form of bundles of concentrated dislocations. Based on the simulation results, the synergy between high strength and high ductility in high entropy alloys can be achieved through the gradient structure. The present study gives a method to better understanding the deformation mechanisms and mechanical properties of high entropy alloys with gradient structure.","PeriodicalId":18300,"journal":{"name":"MatSciRN: Other Materials Processing & Manufacturing (Topic)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74933491","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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