Pub Date : 2023-09-16DOI: 10.21152/1750-9548.17.3.269
Hollow cylindrical and truncated conical shells depict enhanced torsional and shear resistance compared to beams and plates and are ubiquitously used in structures in aeronautics, submarines, wind turbines, pressure vessels, and transmission pylons. Upon extensive localised blast, these elements undergo local and global deformation and failure. The detrimental damage to the shell depends on the stand-off and charge mass and is proportional to the emerged local dynamic stresses and inelastic deformations. Large localised translations relocate the structure’s original pivot point and induce global rotations about the new one which raises the probability of structural collapse. In this work, we examine large plastic deformations of hollow cylindrical and truncated conical shells subject to a range of pulse pressures emanated from high explosives. Fluid-Structure Interaction (FSI)-based Finite Element (FE) models were developed to discern the characteristics of blasts at various stand-offs and functions were proposed to link load parameters to structural, material, and geometric properties.
{"title":"Dynamic response of blast loaded Hollow Cylindrical and Truncated Conical shells","authors":"","doi":"10.21152/1750-9548.17.3.269","DOIUrl":"https://doi.org/10.21152/1750-9548.17.3.269","url":null,"abstract":"Hollow cylindrical and truncated conical shells depict enhanced torsional and shear resistance compared to beams and plates and are ubiquitously used in structures in aeronautics, submarines, wind turbines, pressure vessels, and transmission pylons. Upon extensive localised blast, these elements undergo local and global deformation and failure. The detrimental damage to the shell depends on the stand-off and charge mass and is proportional to the emerged local dynamic stresses and inelastic deformations. Large localised translations relocate the structure’s original pivot point and induce global rotations about the new one which raises the probability of structural collapse. In this work, we examine large plastic deformations of hollow cylindrical and truncated conical shells subject to a range of pulse pressures emanated from high explosives. Fluid-Structure Interaction (FSI)-based Finite Element (FE) models were developed to discern the characteristics of blasts at various stand-offs and functions were proposed to link load parameters to structural, material, and geometric properties.","PeriodicalId":51903,"journal":{"name":"International Journal of Multiphysics","volume":"166 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135307037","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}
Pub Date : 2023-09-16DOI: 10.21152/1750-9548.17.3.289
The parameters of diaphragm spring are optimized and the dimensional parameters in this design are determined with careful derivation. The global optimization feature of the genetic algorithm is used to optimize the diaphragm spring and compared with the damping effect of the standard algorithms. The results show that the optimization design can significantly reduce the force and realize vibration control of the clutch when the design requirements are met. Due to the large error in calculating the vibration characteristics of diaphragm spring by the commonly used A-L method, the finite element method is used to study the influence of the separation finger structure on the load-deflection characteristics of diaphragm spring. To this end, three different window shapes of diaphragm springs are verified in real-life measurements, and the effective pressure test data for three types of diaphragm springs (type A, type B and type C) are selected. Finally, the load displacement of the peak and valley is obtained by summing their averages under loading and unloading of each diaphragm spring model. Moreover, a new method for calculating the vibration characteristics is obtained by introducing the genetic algorithms into the optimal design of diaphragm springs. Compared the A-L method, the finite element method and the proposed method with the measured data, it is verified that the proposed method has high accuracy in calculating the vibration characteristics of diaphragm springs.
{"title":"Study on optimal design and vibration characteristics of diaphragm spring based on Genetic algorithm","authors":"","doi":"10.21152/1750-9548.17.3.289","DOIUrl":"https://doi.org/10.21152/1750-9548.17.3.289","url":null,"abstract":"The parameters of diaphragm spring are optimized and the dimensional parameters in this design are determined with careful derivation. The global optimization feature of the genetic algorithm is used to optimize the diaphragm spring and compared with the damping effect of the standard algorithms. The results show that the optimization design can significantly reduce the force and realize vibration control of the clutch when the design requirements are met. Due to the large error in calculating the vibration characteristics of diaphragm spring by the commonly used A-L method, the finite element method is used to study the influence of the separation finger structure on the load-deflection characteristics of diaphragm spring. To this end, three different window shapes of diaphragm springs are verified in real-life measurements, and the effective pressure test data for three types of diaphragm springs (type A, type B and type C) are selected. Finally, the load displacement of the peak and valley is obtained by summing their averages under loading and unloading of each diaphragm spring model. Moreover, a new method for calculating the vibration characteristics is obtained by introducing the genetic algorithms into the optimal design of diaphragm springs. Compared the A-L method, the finite element method and the proposed method with the measured data, it is verified that the proposed method has high accuracy in calculating the vibration characteristics of diaphragm springs.","PeriodicalId":51903,"journal":{"name":"International Journal of Multiphysics","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135307038","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}
Pub Date : 2023-09-16DOI: 10.21152/1750-9548.17.3.333
Manipulating micro(nano)-sized entities in liquid environment is a challenging yet necessary task in nanoscience and nanotechnology development. Due to the small dimensions, viscous behavior dominates the micro(nano)-sized obejcts motion. In this study, a computational fluid dynamic (CFD) approach has been used to investigate hydrodynamic effects on a nanowire (NM) translating an rotating about its long and short axis. Several numerical methods dealing with solid motion in fluid, including some CFD methods and Finite element analysis (FEA), have been compared. The change in drag coefficient with NW length, NW diameter, translational velocity, rotation speed, and wall effects has been researched. As a model, nanowires with 1-10 µm dimensions and 50 nm-250 nm diameters were investigated in liquid, with velocities of 0.5-500 µm/s. Nanowire is rotated about its long axis with an angular velocity of ω=0.25π, 0.5π, 1.0π, 2.0π rad/s, and about its short axis with a fluid flow allow the rotation of the nanowire whose one end is contsrained to a rotational motion around x and y axis. These models were also compared with the existing analytical models. Good agreement was observed between the numerical results and analytical calculations. The FEA model is also repeated in the closed boundary to investigate the wall effects on the nanowire’s motion in liquid environment.
{"title":"A Numerical Study to Investigate the Hydrodynamic Properties of Nanowire Motion in Liquid","authors":"","doi":"10.21152/1750-9548.17.3.333","DOIUrl":"https://doi.org/10.21152/1750-9548.17.3.333","url":null,"abstract":"Manipulating micro(nano)-sized entities in liquid environment is a challenging yet necessary task in nanoscience and nanotechnology development. Due to the small dimensions, viscous behavior dominates the micro(nano)-sized obejcts motion. In this study, a computational fluid dynamic (CFD) approach has been used to investigate hydrodynamic effects on a nanowire (NM) translating an rotating about its long and short axis. Several numerical methods dealing with solid motion in fluid, including some CFD methods and Finite element analysis (FEA), have been compared. The change in drag coefficient with NW length, NW diameter, translational velocity, rotation speed, and wall effects has been researched. As a model, nanowires with 1-10 µm dimensions and 50 nm-250 nm diameters were investigated in liquid, with velocities of 0.5-500 µm/s. Nanowire is rotated about its long axis with an angular velocity of ω=0.25π, 0.5π, 1.0π, 2.0π rad/s, and about its short axis with a fluid flow allow the rotation of the nanowire whose one end is contsrained to a rotational motion around x and y axis. These models were also compared with the existing analytical models. Good agreement was observed between the numerical results and analytical calculations. The FEA model is also repeated in the closed boundary to investigate the wall effects on the nanowire’s motion in liquid environment.","PeriodicalId":51903,"journal":{"name":"International Journal of Multiphysics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135307040","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}
Pub Date : 2023-09-16DOI: 10.21152/1750-9548.17.3.253
Ice accretion on railway overhead contact wires/conductors can cause various critical operational and safety issues such as overloading, arc formation, mass imbalance, and wire galloping. The focus of this multiphase numerical study is to understand and analyze the ice accretion physics on railway overhead powerline conductors at various operating conditions. In this regard, two different geometric shape conductors of 12 mm diameter, 1) a grooved shape contact wire (like an actual railway conductor); 2) a standard circular shape contact wire are used. Computational Fluid Dynamics (CFD) based numerical simulations are carried out for both geometric configurations at different operating parameters such as wind speed, Liquid Water Content (LWC), cloud droplet size distribution, Median Volume Diameter (MVD), and atmospheric temperature. Analysis shows that variation in the operating weather parameters for both geometric configurations considerably affects the ice accretion, both in terms of accreted ice thickness and mass.
{"title":"Atmospheric Ice Accretion on Railway Overhead Powerline Conductors- A Numerical Case Study","authors":"","doi":"10.21152/1750-9548.17.3.253","DOIUrl":"https://doi.org/10.21152/1750-9548.17.3.253","url":null,"abstract":"Ice accretion on railway overhead contact wires/conductors can cause various critical operational and safety issues such as overloading, arc formation, mass imbalance, and wire galloping. The focus of this multiphase numerical study is to understand and analyze the ice accretion physics on railway overhead powerline conductors at various operating conditions. In this regard, two different geometric shape conductors of 12 mm diameter, 1) a grooved shape contact wire (like an actual railway conductor); 2) a standard circular shape contact wire are used. Computational Fluid Dynamics (CFD) based numerical simulations are carried out for both geometric configurations at different operating parameters such as wind speed, Liquid Water Content (LWC), cloud droplet size distribution, Median Volume Diameter (MVD), and atmospheric temperature. Analysis shows that variation in the operating weather parameters for both geometric configurations considerably affects the ice accretion, both in terms of accreted ice thickness and mass.","PeriodicalId":51903,"journal":{"name":"International Journal of Multiphysics","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135307044","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}
Pub Date : 2023-09-16DOI: 10.21152/1750-9548.17.3.349
Wearable technology has broad market prospects in the military, fire protection, medical and health, sports and other fields under its ability to effectively solve practical application needs. Self-powered energy systems with miniaturized, light-weight, highly flexible, stretchable, bendable, and wearable properties have received extensive attention in the industry as they can meet the needs of new-generation wearable electronic devices. Firstly, the article summarizes the recent progress and existing problems of flexible solar cells, flexible triboelectric nanogenerators, flexible piezoelectric nanogenerators, flexible thermoelectric generators, and energy harvesting devices for sweat power generation. Secondly, the development and challenges of flexible lithium-ion batteries and flexible super capacitors for energy storage devices are summarized. The research progress of energy management strategies is also discussed. Then, the main applications of self-powered systems in wearable electronic devices are introduced, including Individual Soldier Equipment, Protective Clothing Devices and Smart Wearable Electronic Devices. Finally, the future development direction of self-powered energy systems for wearable electronic devices is discussed.
{"title":"Review on Self-Sustainable Power Generation Technologies for Future Typical Wearable Applications","authors":"","doi":"10.21152/1750-9548.17.3.349","DOIUrl":"https://doi.org/10.21152/1750-9548.17.3.349","url":null,"abstract":"Wearable technology has broad market prospects in the military, fire protection, medical and health, sports and other fields under its ability to effectively solve practical application needs. Self-powered energy systems with miniaturized, light-weight, highly flexible, stretchable, bendable, and wearable properties have received extensive attention in the industry as they can meet the needs of new-generation wearable electronic devices. Firstly, the article summarizes the recent progress and existing problems of flexible solar cells, flexible triboelectric nanogenerators, flexible piezoelectric nanogenerators, flexible thermoelectric generators, and energy harvesting devices for sweat power generation. Secondly, the development and challenges of flexible lithium-ion batteries and flexible super capacitors for energy storage devices are summarized. The research progress of energy management strategies is also discussed. Then, the main applications of self-powered systems in wearable electronic devices are introduced, including Individual Soldier Equipment, Protective Clothing Devices and Smart Wearable Electronic Devices. Finally, the future development direction of self-powered energy systems for wearable electronic devices is discussed.","PeriodicalId":51903,"journal":{"name":"International Journal of Multiphysics","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135305586","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}
Pub Date : 2023-09-16DOI: 10.21152/1750-9548.17.3.235
The modeling of atmospheric ice accretion on duplex cylinders received a limited attention, with modeling carried by Wagner and Qing et al. The publicly available experimental data about the ice accretion on the duplex cylinders is limited to experiments of Qing et al. and Veerakumar et al. When comparing the data of Wagner and Qing et al. with the results of Veerakumar et al., the major difference is the airflow behavior in the wake of the windward cylinder, the extent of the wake and recirculation bubble, and the velocity distribution in the wake. Thus, its needed to study the effect of the turbulence model on the airflow behavior of duplex cylinders, with focus being the behavior of the wake of the windward cylinder. This study reports the simulation results of the complex airflow behavior of duplex circular cylinder bundle obtained using several turbulence models employed by commercial CFD code.
双圆柱体上大气冰堆积的模拟受到了有限的关注，由Wagner和Qing等人进行了模拟。关于双筒冰的吸积的公开实验数据仅限于Qing et al.和Veerakumar et al.的实验。将Wagner和Qing等人的数据与Veerakumar等人的结果进行对比时，主要的差异在于迎风圆柱尾迹中的气流行为、尾迹和再循环气泡的范围以及尾迹中的速度分布。因此，有必要研究湍流模型对双柱体气流特性的影响，重点研究迎风柱体的尾迹特性。本文报道了利用商业CFD程序中几种湍流模型对双圆柱束复杂气流特性的模拟结果。
{"title":"Study of Airflow Behavior for Duplex Circular Cylinders","authors":"","doi":"10.21152/1750-9548.17.3.235","DOIUrl":"https://doi.org/10.21152/1750-9548.17.3.235","url":null,"abstract":"The modeling of atmospheric ice accretion on duplex cylinders received a limited attention, with modeling carried by Wagner and Qing et al. The publicly available experimental data about the ice accretion on the duplex cylinders is limited to experiments of Qing et al. and Veerakumar et al. When comparing the data of Wagner and Qing et al. with the results of Veerakumar et al., the major difference is the airflow behavior in the wake of the windward cylinder, the extent of the wake and recirculation bubble, and the velocity distribution in the wake. Thus, its needed to study the effect of the turbulence model on the airflow behavior of duplex cylinders, with focus being the behavior of the wake of the windward cylinder. This study reports the simulation results of the complex airflow behavior of duplex circular cylinder bundle obtained using several turbulence models employed by commercial CFD code.","PeriodicalId":51903,"journal":{"name":"International Journal of Multiphysics","volume":"166 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135307042","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}
Pub Date : 2023-09-16DOI: 10.21152/1750-9548.17.3.315
Selection of the correct parameters during the friction stir welding process is vital. The study entailed an analysis of the mechanical properties and microstructure of aluminium 6082T651 welded by friction stir welding at different spindle rotational speeds (500, 550, 600 and 650 rpm) and constant acceleration of 250 mm/min. Surface roughness of the welded samples was assessed according to ISO 25178. ASTM E384 and ASTM E8/E8M-09 standards were used for hardness and tensile tests respectively. The results show the highest tool rotational speed (650 rpm) to have produced the greatest weld surface roughness, of approximately 19.56 µm. The weldments made by friction stir welding at the highest tool rotational speed of 650 rpm displayed the best mechanical properties.
{"title":"Experimental investigation into the effect of spindle rotational speed on surface roughness and mechanical properties of aluminium 6082T651 welded by friction stir process","authors":"","doi":"10.21152/1750-9548.17.3.315","DOIUrl":"https://doi.org/10.21152/1750-9548.17.3.315","url":null,"abstract":"Selection of the correct parameters during the friction stir welding process is vital. The study entailed an analysis of the mechanical properties and microstructure of aluminium 6082T651 welded by friction stir welding at different spindle rotational speeds (500, 550, 600 and 650 rpm) and constant acceleration of 250 mm/min. Surface roughness of the welded samples was assessed according to ISO 25178. ASTM E384 and ASTM E8/E8M-09 standards were used for hardness and tensile tests respectively. The results show the highest tool rotational speed (650 rpm) to have produced the greatest weld surface roughness, of approximately 19.56 µm. The weldments made by friction stir welding at the highest tool rotational speed of 650 rpm displayed the best mechanical properties.","PeriodicalId":51903,"journal":{"name":"International Journal of Multiphysics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135307045","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}
Pub Date : 2020-03-31DOI: 10.21152/1750-9548.14.1.53
E. Holzbecher
Convective motions are a multi-physics phenomenon, in which flow and transport processes interact in a two-way coupling. The density of the fluid depends on the value of transport variable and this back-coupling leads to non-linear behaviour. For the classical constellation of a closed fluid container heated from below convective motions appear, when a critical threshold for the Rayleigh number is exceeded. The heat transfer due to convection is much higher than in the case of pure conduction. Here systems of three layers are examined in detail. Using numerical CFD modelling it is shown that in layered systems different convective flow patterns appear than in the single layer case. The number and constellation of convection cells characterize steady flow patterns. Using a parametric sweep over the relevant parameter range of layer Rayleigh numbers and layer thicknesses we determine diagrams that show the excess heat or mass transfer of the dominant convection patterns, measured by the Nusselt- or Sherwood numbers.
{"title":"Convective Transport through Porous Layers","authors":"E. Holzbecher","doi":"10.21152/1750-9548.14.1.53","DOIUrl":"https://doi.org/10.21152/1750-9548.14.1.53","url":null,"abstract":"Convective motions are a multi-physics phenomenon, in which flow and transport processes interact in a two-way coupling. The density of the fluid depends on the value of transport variable and this back-coupling leads to non-linear behaviour. For the classical constellation of a closed fluid container heated from below convective motions appear, when a critical threshold for the Rayleigh number is exceeded. The heat transfer due to convection is much higher than in the case of pure conduction. Here systems of three layers are examined in detail. Using numerical CFD modelling it is shown that in layered systems different convective flow patterns appear than in the single layer case. The number and constellation of convection cells characterize steady flow patterns. Using a parametric sweep over the relevant parameter range of layer Rayleigh numbers and layer thicknesses we determine diagrams that show the excess heat or mass transfer of the dominant convection patterns, measured by the Nusselt- or Sherwood numbers.","PeriodicalId":51903,"journal":{"name":"International Journal of Multiphysics","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2020-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44160248","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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