J. Liaw, Bing-Xian Chen, Yun-Cheng Ku, Chun-Yi Yang, Chun-Wei Lin, M. Kuo
The optomechanical manipulation of an optical vortex beam (Bessel beam) upon a single gold nanoparticle (GNP) was studied theoretically. This structured light carries spin angular momentum (SAM) and orbital angular momentum (OAM) simultaneously via the spin-orbit interaction (SOI) of light. Due to the plasmon-enhanced light absorption and scattering of GNP, the SAM and OAM of photons are transferred to GNP, exhibited by the spin and orbital motions of GNP. The optical force and torque upon GNP are analyzed through the surface integrals of Maxwell's stress tensor. We found that there are specific stable circular orbits of GNP through the simulation of GNP's equation of motion; the revolution direction depends on the sign of the order of Bessel beam. If the order of Bessel beam is a positive integer, the GNP performs an orbital motion with a counterclockwise revolution. On the contrary, for a Bessel beam of a negative order, a clockwise revolution of GNP is induced. Additionally, the spin direction of GNP depends on the handedness of light: right-hand or left-hand circular polarization.
{"title":"Optical manipulation of optical vortex beam on gold nanoparticle","authors":"J. Liaw, Bing-Xian Chen, Yun-Cheng Ku, Chun-Yi Yang, Chun-Wei Lin, M. Kuo","doi":"10.1093/jom/ufac047","DOIUrl":"https://doi.org/10.1093/jom/ufac047","url":null,"abstract":"The optomechanical manipulation of an optical vortex beam (Bessel beam) upon a single gold nanoparticle (GNP) was studied theoretically. This structured light carries spin angular momentum (SAM) and orbital angular momentum (OAM) simultaneously via the spin-orbit interaction (SOI) of light. Due to the plasmon-enhanced light absorption and scattering of GNP, the SAM and OAM of photons are transferred to GNP, exhibited by the spin and orbital motions of GNP. The optical force and torque upon GNP are analyzed through the surface integrals of Maxwell's stress tensor. We found that there are specific stable circular orbits of GNP through the simulation of GNP's equation of motion; the revolution direction depends on the sign of the order of Bessel beam. If the order of Bessel beam is a positive integer, the GNP performs an orbital motion with a counterclockwise revolution. On the contrary, for a Bessel beam of a negative order, a clockwise revolution of GNP is induced. Additionally, the spin direction of GNP depends on the handedness of light: right-hand or left-hand circular polarization.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61542149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a formulation for isogeometric Kirchhoff–Love shell analysis on complex CAD models consisting of multiple trimmed patches. The method is based on the penalty coupling method presented in Herrema AJ, Johnson EL, Proserpio D, Wu MCH, Kiendl J, Hsu MC (Penalty coupling of non-matching isogeometric Kirchhoff–Love shell patches with application to composite wind turbine blades. Computer Methods in Applied Mechanics and Engineering 2019;346:810–840.) and extended to the application on arbitrary coupling curves defined either in the physical or parametric space. We present the detailed formulation ready for implementation. Different numerical tests demonstrate the accuracy and applicability of the method.
我们提出了一个由多个裁剪补丁组成的复杂CAD模型的等几何Kirchhoff-Love壳分析公式。该方法基于Herrema AJ, Johnson EL, Proserpio D, Wu MCH, Kiendl J, Hsu MC(非匹配等几何Kirchhoff-Love壳块的惩罚耦合)中提出的惩罚耦合方法，并应用于复合风力机叶片。应用力学与工程中的计算机方法2019;346:810-840 .)，并扩展到在物理或参数空间中定义的任意耦合曲线上的应用。我们提出了准备实施的详细方案。不同的数值试验验证了该方法的准确性和适用性。
{"title":"Penalty coupling of trimmed isogeometric Kirchhoff–Love shell patches","authors":"D. Proserpio, J. Kiendl","doi":"10.1093/jom/ufac008","DOIUrl":"https://doi.org/10.1093/jom/ufac008","url":null,"abstract":"We present a formulation for isogeometric Kirchhoff–Love shell analysis on complex CAD models consisting of multiple trimmed patches. The method is based on the penalty coupling method presented in Herrema AJ, Johnson EL, Proserpio D, Wu MCH, Kiendl J, Hsu MC (Penalty coupling of non-matching isogeometric Kirchhoff–Love shell patches with application to composite wind turbine blades. Computer Methods in Applied Mechanics and Engineering 2019;346:810–840.) and extended to the application on arbitrary coupling curves defined either in the physical or parametric space. We present the detailed formulation ready for implementation. Different numerical tests demonstrate the accuracy and applicability of the method.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61539649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chung-Yue Wang, V. S. Nguyen, M. I. Syamsi, Hao-Lin Wang
Most of the existing analytical solutions to the vibration of cable networks interconnected by cross-ties are developed based on string theory, where the effect of cable bending rigidity on cable vibration is ignored. However, the bending rigidity of cables strongly influences the natural frequencies and vibration mode shapes of short and stout cables and long cables at higher modes. Hence, this paper considers cable bending rigidity to form a closed-form solution that can be used in determining the natural frequencies and mode shapes of cable networks. The analytical solution of the cable network model with hinged-end boundary conditions is derived. It can be combined with other existing techniques to analyze the dynamic behaviors of a two-cable network with partly fixed supports. The analytical solution derived from this paper can be degenerated to the same solution without considering the cable bending rigidity in previous studies. The accuracy of this analytical solution considering cable bending rigidity is verified by finite element analysis. The effects of bending rigidity on the vibration frequencies and modes of the cable network with inclined and flexible cross-link are investigated in detail. This analytical solution can be applied to backward analysis to identify the cable tension of a two-cable network with partly fixed supports.
{"title":"Vibration of two in-plane simply supported bending cables interconnected by a flexible cross-link","authors":"Chung-Yue Wang, V. S. Nguyen, M. I. Syamsi, Hao-Lin Wang","doi":"10.1093/jom/ufac026","DOIUrl":"https://doi.org/10.1093/jom/ufac026","url":null,"abstract":"Most of the existing analytical solutions to the vibration of cable networks interconnected by cross-ties are developed based on string theory, where the effect of cable bending rigidity on cable vibration is ignored. However, the bending rigidity of cables strongly influences the natural frequencies and vibration mode shapes of short and stout cables and long cables at higher modes. Hence, this paper considers cable bending rigidity to form a closed-form solution that can be used in determining the natural frequencies and mode shapes of cable networks. The analytical solution of the cable network model with hinged-end boundary conditions is derived. It can be combined with other existing techniques to analyze the dynamic behaviors of a two-cable network with partly fixed supports. The analytical solution derived from this paper can be degenerated to the same solution without considering the cable bending rigidity in previous studies. The accuracy of this analytical solution considering cable bending rigidity is verified by finite element analysis. The effects of bending rigidity on the vibration frequencies and modes of the cable network with inclined and flexible cross-link are investigated in detail. This analytical solution can be applied to backward analysis to identify the cable tension of a two-cable network with partly fixed supports.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61540388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Changliang Han, Jingying Duan, Sibei Yin, Xibing Li
In this paper, an investigation into flow and heat transfer performance of supercritical methane (S-CH4) in a 180-degree curved circular duct has been numerically carried out. The mathematical description of energy equation induced by the Dean vortices under the Cartesian-coordinate is first deduced. After validating the dynamic computational fluid dynamics model and method against the public experimental data, the effect of mass flux on the thermodynamics properties of S-CH4 is revealed. The calculation results show that due to the centrifugal force, the low temperature of S-CH4 gathers near the outer wall generatrix. Meanwhile, owing to the existence of multiple Dean vortices, all thermophysical parameters on the 90° cross-section are symmetrically concave along the vertical axis. The core position of multiple Dean vortices inside the curved duct is closer to the inner wall generatrix, which makes the velocity fluctuation greater. The maximum value of circumferential heat transfer coefficient on different cross-sections differs, and the non-uniform flow development process occurs inside the curved duct. Compared to the straight duct, when the mass fluxes are respectively 300 kg/m2 · s and 600 kg/m2 · s, the magnitude of increase in heat transfer coefficient of curved duct presents 18.8% and 23.5%. In addition, the forced convection caused by the secondary flow inside curved duct is so strong that the natural convection by the gravity could be neglected. The research outcome is of vital importance for the optimization design of liquefied natural gas vaporizer.
{"title":"Study on supercritical methane flow and heat transfer performance in a 180-degree curved duct","authors":"Changliang Han, Jingying Duan, Sibei Yin, Xibing Li","doi":"10.1093/jom/ufac027","DOIUrl":"https://doi.org/10.1093/jom/ufac027","url":null,"abstract":"In this paper, an investigation into flow and heat transfer performance of supercritical methane (S-CH4) in a 180-degree curved circular duct has been numerically carried out. The mathematical description of energy equation induced by the Dean vortices under the Cartesian-coordinate is first deduced. After validating the dynamic computational fluid dynamics model and method against the public experimental data, the effect of mass flux on the thermodynamics properties of S-CH4 is revealed. The calculation results show that due to the centrifugal force, the low temperature of S-CH4 gathers near the outer wall generatrix. Meanwhile, owing to the existence of multiple Dean vortices, all thermophysical parameters on the 90° cross-section are symmetrically concave along the vertical axis. The core position of multiple Dean vortices inside the curved duct is closer to the inner wall generatrix, which makes the velocity fluctuation greater. The maximum value of circumferential heat transfer coefficient on different cross-sections differs, and the non-uniform flow development process occurs inside the curved duct. Compared to the straight duct, when the mass fluxes are respectively 300 kg/m2 · s and 600 kg/m2 · s, the magnitude of increase in heat transfer coefficient of curved duct presents 18.8% and 23.5%. In addition, the forced convection caused by the secondary flow inside curved duct is so strong that the natural convection by the gravity could be neglected. The research outcome is of vital importance for the optimization design of liquefied natural gas vaporizer.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61540392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pores play an important role in the failure analysis of metal castings. During the solidification process, slag inclusions such as oxides, nitrides and sulfides may form around the pores. This paper provides an analytical solution for an inclusion layer bonded to a square pore under edge dislocation or a concentrated load. Based on the mapping method and analytical continuation theorem, both sliding and climbing forces as well as interfacial stresses induced by a dislocation or concentrated load are obtained in a closed form. The results indicate that an inclusion layer with a larger (or smaller) shape factor would result in a stable equilibrium position near (or far from) the interface. When the shape factor decreases, the stable equilibrium position moves away from the interface if the stiffness of the inclusion layer increases. For a concentrated load, the interfacial stresses increased with the elastic mismatch and corner sharpness. These findings could improve the compatibility between the matrix and inclusion layer in metallurgical manufacturing systems.
{"title":"Stress analysis of an inclusion layer bonded to an irregularly shaped pore under an edge dislocation or a concentrated load","authors":"Y. Liao, S. Tseng, C. Chao","doi":"10.1093/jom/ufac028","DOIUrl":"https://doi.org/10.1093/jom/ufac028","url":null,"abstract":"Pores play an important role in the failure analysis of metal castings. During the solidification process, slag inclusions such as oxides, nitrides and sulfides may form around the pores. This paper provides an analytical solution for an inclusion layer bonded to a square pore under edge dislocation or a concentrated load. Based on the mapping method and analytical continuation theorem, both sliding and climbing forces as well as interfacial stresses induced by a dislocation or concentrated load are obtained in a closed form. The results indicate that an inclusion layer with a larger (or smaller) shape factor would result in a stable equilibrium position near (or far from) the interface. When the shape factor decreases, the stable equilibrium position moves away from the interface if the stiffness of the inclusion layer increases. For a concentrated load, the interfacial stresses increased with the elastic mismatch and corner sharpness. These findings could improve the compatibility between the matrix and inclusion layer in metallurgical manufacturing systems.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61540421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jeng-Tzong Chen, Hao-Chen Kao, Jia-Wei Lee, Ying-Te Lee
In this paper, we extended the previous experience to solve the vibration problem of a finite bar with a viscously damped boundary and the support motion on the other side. Two analytical methods, the mode superposition method in conjunction with the quasi-static decomposition method and the method of diamond rule based on the method of characteristics, were employed to derive two analytical solutions. One is a series solution by using the mode superposition method. The other is an exact solution by using the method of diamond rule. The non-conservative system with an external damper is solved straightforward by using the method of diamond rule to avoid the complex-valued eigen system. Agreement is made well. Both advantages and disadvantages of two methods were discussed.
{"title":"Support motion of a finite bar with a viscously damped boundary","authors":"Jeng-Tzong Chen, Hao-Chen Kao, Jia-Wei Lee, Ying-Te Lee","doi":"10.1093/jom/ufac035","DOIUrl":"https://doi.org/10.1093/jom/ufac035","url":null,"abstract":"In this paper, we extended the previous experience to solve the vibration problem of a finite bar with a viscously damped boundary and the support motion on the other side. Two analytical methods, the mode superposition method in conjunction with the quasi-static decomposition method and the method of diamond rule based on the method of characteristics, were employed to derive two analytical solutions. One is a series solution by using the mode superposition method. The other is an exact solution by using the method of diamond rule. The non-conservative system with an external damper is solved straightforward by using the method of diamond rule to avoid the complex-valued eigen system. Agreement is made well. Both advantages and disadvantages of two methods were discussed.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61541055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The focus of this paper is to look at the development of the field of Applied Mechanics from past to present. With a historical perspective, we can better understand the important contributions and achievements that the field of Applied Mechanics has played in our society. The paper will begin by reviewing the history of Applied Mechanics over the past 400 years, followed by looking at engineering education in the 19th and 20th centuries, and then examining the evolution of Applied Mechanics in society today. We will discuss some of today's interdisciplinary developments in Applied Mechanics such as the buckling of ferromagnetic materials in strong magnetic fields, mechanics-based nanoscale measurement instruments, radio frequency microelectromical systems, biochips and nanotechnology. Finally, we will conclude by looking at Maslow's Five-level Theory of Human Needs and provide several innovative examples to further implement innovative models of Applied Mechanics research to teach more advanced knowledge in today's artificial intelligence and information technology based society.
{"title":"The field of applied mechanics: historical outlook from past to present and its implications for future applications","authors":"Chih-Kung Lee","doi":"10.1093/jom/ufac042","DOIUrl":"https://doi.org/10.1093/jom/ufac042","url":null,"abstract":"The focus of this paper is to look at the development of the field of Applied Mechanics from past to present. With a historical perspective, we can better understand the important contributions and achievements that the field of Applied Mechanics has played in our society. The paper will begin by reviewing the history of Applied Mechanics over the past 400 years, followed by looking at engineering education in the 19th and 20th centuries, and then examining the evolution of Applied Mechanics in society today. We will discuss some of today's interdisciplinary developments in Applied Mechanics such as the buckling of ferromagnetic materials in strong magnetic fields, mechanics-based nanoscale measurement instruments, radio frequency microelectromical systems, biochips and nanotechnology. Finally, we will conclude by looking at Maslow's Five-level Theory of Human Needs and provide several innovative examples to further implement innovative models of Applied Mechanics research to teach more advanced knowledge in today's artificial intelligence and information technology based society.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61541661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Chou, Avdhesh Kumar, Po-Chun Lu, Ching-Yao Chen
An alternating injection scheme is experimentally employed to study the mixing performance of miscible viscous fluids in a radial Hele-Shaw cell. The concept of the covered area is introduced to quantify the mixing efficiency and various numerical simulations are performed to support and verify the experimental results. It has been observed that the alternating injection can improve the mixing efficiency, depending on the prominence of the channeling interactions. The alternating injection can effectively improve the mixing efficiency under certain conditions, where weaker fingering interactions are dominated by diffusive mixing. However, the results under the high Péclet number conditions are inconsistent, i.e. the mixing efficiency is reduced due to the emergence of orderly viscous fingers prevailing random chaotic interactions. This phenomenon is similar to the channeling interaction in the heterogeneous permeability fields in which less viscous fluid flows through favorable paths due to the local pressure difference between two successively emerging fingers.
{"title":"Miscible fluids mixing via alternating injection in a radial Hele-Shaw cell: experimental and numerical studies","authors":"C. Chou, Avdhesh Kumar, Po-Chun Lu, Ching-Yao Chen","doi":"10.1093/jom/ufac043","DOIUrl":"https://doi.org/10.1093/jom/ufac043","url":null,"abstract":"An alternating injection scheme is experimentally employed to study the mixing performance of miscible viscous fluids in a radial Hele-Shaw cell. The concept of the covered area is introduced to quantify the mixing efficiency and various numerical simulations are performed to support and verify the experimental results. It has been observed that the alternating injection can improve the mixing efficiency, depending on the prominence of the channeling interactions. The alternating injection can effectively improve the mixing efficiency under certain conditions, where weaker fingering interactions are dominated by diffusive mixing. However, the results under the high Péclet number conditions are inconsistent, i.e. the mixing efficiency is reduced due to the emergence of orderly viscous fingers prevailing random chaotic interactions. This phenomenon is similar to the channeling interaction in the heterogeneous permeability fields in which less viscous fluid flows through favorable paths due to the local pressure difference between two successively emerging fingers.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61541749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Enling Tang, Zhen Zhang, Chuang Chen, Yafei Han, Mengzhou Chang, K. Guo, Liping He
In the process of underwater motion, the trajectory of the projectile will be greatly disturbed due to the complicated underwater environment and cavitation effect. In order to study the effect of the ice water mixture on projectile motion, the experiments of a titanium alloy slender body with a truncated conical and plat warhead passing through ice and water mixture have been performed by using a one-stage light gas gun loading system, an overpressure sensor measurement system and a high-speed camera acquisition system in this paper. The experimental results show that the volume of the cavity generated by the slender body with a small length-to-diameter ratio is larger, and the slender body deflects in the process of movement. For a slender body with a large length-to-diameter ratio, the cavity formed is closer to the central axis and the maximum radial size of the cavity. No matter the warhead shapes are truncated conical or plat warhead, the diameter and lasting time of the cavity increase with the increase of the slender body's velocities. Under the condition that the length-to-diameter ratio and the velocity of the slender bodies are similar, the overall evolutionary trend of the overpressure generated by two kinds of slender bodies is similar. But the fluctuation range of the overpressure amplitude of the plat warhead is small, the curve oscillation amplitude of the adjacent time is large and the peak value of the overpressure for the truncated conical warhead is large. Under the same ratio of length to diameter, the velocity has no obvious influence on the trajectory of the slender body after hitting the ice particles. When the slender body collides with ice particles, the deflection angle of its trajectory is larger than that of impacting on the edge of ice particles. When the slender body collides with the ice particles, the interaction between the ice particles and the slender body is large, and the deflection angle of the slender body is larger after impact.
{"title":"Dynamic response of slender body passing through ice and water mixture at high velocity","authors":"Enling Tang, Zhen Zhang, Chuang Chen, Yafei Han, Mengzhou Chang, K. Guo, Liping He","doi":"10.1093/jom/ufac016","DOIUrl":"https://doi.org/10.1093/jom/ufac016","url":null,"abstract":"In the process of underwater motion, the trajectory of the projectile will be greatly disturbed due to the complicated underwater environment and cavitation effect. In order to study the effect of the ice water mixture on projectile motion, the experiments of a titanium alloy slender body with a truncated conical and plat warhead passing through ice and water mixture have been performed by using a one-stage light gas gun loading system, an overpressure sensor measurement system and a high-speed camera acquisition system in this paper. The experimental results show that the volume of the cavity generated by the slender body with a small length-to-diameter ratio is larger, and the slender body deflects in the process of movement. For a slender body with a large length-to-diameter ratio, the cavity formed is closer to the central axis and the maximum radial size of the cavity. No matter the warhead shapes are truncated conical or plat warhead, the diameter and lasting time of the cavity increase with the increase of the slender body's velocities. Under the condition that the length-to-diameter ratio and the velocity of the slender bodies are similar, the overall evolutionary trend of the overpressure generated by two kinds of slender bodies is similar. But the fluctuation range of the overpressure amplitude of the plat warhead is small, the curve oscillation amplitude of the adjacent time is large and the peak value of the overpressure for the truncated conical warhead is large. Under the same ratio of length to diameter, the velocity has no obvious influence on the trajectory of the slender body after hitting the ice particles. When the slender body collides with ice particles, the deflection angle of its trajectory is larger than that of impacting on the edge of ice particles. When the slender body collides with the ice particles, the interaction between the ice particles and the slender body is large, and the deflection angle of the slender body is larger after impact.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61539775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kendrick M. Shepherd, X. Gu, R. Hiemstra, T. Hughes
Extracting quadrilateral layouts from surface triangulations is an important step in texture mapping, semi-structured quadrilateral meshing for traditional analysis and spline reconstruction for isogeometric analysis. Current methods struggle to yield high-quality layouts with appropriate connectivity between singular nodes (known as “extraordinary points” for spline representations) without resorting to either mixed-integer optimization or manual constraint prescription. The first of these is computationally expensive and comes with no guarantees, while the second is laborious and error-prone. In this work, we rigorously characterize curves in a quadrilateral layout up to homotopy type and use this information to quickly define high-quality connectivity constraints between singular nodes. The mathematical theory is accompanied by appropriate computational algorithms. The efficacy of the proposed method is demonstrated in generating quadrilateral layouts on the United States Army’s DEVCOM Generic Hull vehicle and parts of a bilinear quadrilateral finite element mesh (with some linear triangles) of a 1996 Dodge Neon.
{"title":"Quadrilateral layout generation and optimization using equivalence classes of integral curves: theory and application to surfaces with boundaries","authors":"Kendrick M. Shepherd, X. Gu, R. Hiemstra, T. Hughes","doi":"10.1093/jom/ufac002","DOIUrl":"https://doi.org/10.1093/jom/ufac002","url":null,"abstract":"Extracting quadrilateral layouts from surface triangulations is an important step in texture mapping, semi-structured quadrilateral meshing for traditional analysis and spline reconstruction for isogeometric analysis. Current methods struggle to yield high-quality layouts with appropriate connectivity between singular nodes (known as “extraordinary points” for spline representations) without resorting to either mixed-integer optimization or manual constraint prescription. The first of these is computationally expensive and comes with no guarantees, while the second is laborious and error-prone. In this work, we rigorously characterize curves in a quadrilateral layout up to homotopy type and use this information to quickly define high-quality connectivity constraints between singular nodes. The mathematical theory is accompanied by appropriate computational algorithms. The efficacy of the proposed method is demonstrated in generating quadrilateral layouts on the United States Army’s DEVCOM Generic Hull vehicle and parts of a bilinear quadrilateral finite element mesh (with some linear triangles) of a 1996 Dodge Neon.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61539131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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