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Penalty coupling of trimmed isogeometric Kirchhoff–Love shell patches 裁剪等几何Kirchhoff-Love壳块的惩罚耦合
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac008
D. Proserpio, J. Kiendl
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。
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引用次数: 4
Optical manipulation of optical vortex beam on gold nanoparticle 光涡旋光束对金纳米粒子的光学操纵
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac047
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.
从理论上研究了光涡旋光束(贝塞尔光束)对单个金纳米粒子的光力学作用。这种结构光通过光的自旋-轨道相互作用(SOI)同时携带自旋角动量(SAM)和轨道角动量(OAM)。由于等离子体增强了GNP的光吸收和散射,光子的SAM和OAM被转移到GNP中,表现为GNP的自旋和轨道运动。通过麦克斯韦应力张量的表面积分分析了光力和扭矩对GNP的影响。通过对GNP运动方程的模拟,发现GNP存在特定的稳定圆轨道;旋转方向取决于贝塞尔光束阶数的符号。如果贝塞尔光束阶数为正整数,则GNP进行逆时针旋转的轨道运动。相反,对于负阶贝塞尔光束,GNP会发生顺时针旋转。此外,GNP的自旋方向取决于光的手性:右旋或左旋圆偏振。
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引用次数: 1
Vibration of two in-plane simply supported bending cables interconnected by a flexible cross-link 用柔性交联连接的平面内简支弯曲电缆的振动
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac026
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.
现有的交叉拉索网络振动解析解大多基于弦理论,忽略了拉索弯曲刚度对拉索振动的影响。然而,索的弯曲刚度对短、粗索和长索在高模态下的固有频率和振型有很大的影响。因此,本文考虑电缆的弯曲刚度,形成一个封闭的解,可用于确定电缆网络的固有频率和模态振型。导出了具有铰端边界条件的电缆网络模型的解析解。该方法可与现有的其他方法相结合,用于分析部分固定支承的双缆网络的动力特性。本文导出的解析解可以在不考虑前人研究中索的弯曲刚度的情况下退化为相同的解析解。通过有限元分析验证了考虑电缆弯曲刚度的解析解的准确性。详细研究了弯曲刚度对斜交联和柔性交联索网振动频率和振型的影响。该解析解可用于判别部分固定支承双索网的索张力的逆向分析。
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引用次数: 2
Study on supercritical methane flow and heat transfer performance in a 180-degree curved duct 180度弯曲管道内超临界甲烷流动及换热性能研究
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac027
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.
本文对超临界甲烷(S-CH4)在180度弯曲圆管内的流动和换热性能进行了数值研究。首先推导了直角坐标系下迪安涡诱导能量方程的数学描述。通过对动力学计算流体力学模型和方法与公开实验数据的验证,揭示了质量通量对S-CH4热力学性质的影响。计算结果表明,由于离心力的作用,S-CH4的低温聚集在外壁母线附近。同时,由于多个Dean涡的存在,90°截面上的热物性参数沿垂直轴对称凹。弯曲导管内多个Dean涡的核心位置更靠近内壁母线,使得速度波动更大。不同截面上的周向换热系数最大值不同,弯曲管道内部出现非均匀流动发展过程。与直管相比,当质量通量分别为300 kg/m2·s和600 kg/m2·s时,弯曲管的换热系数增加幅度分别为18.8%和23.5%。此外,弯管内二次流引起的强制对流非常强,重力作用下的自然对流可以忽略不计。研究成果对液化天然气汽化器的优化设计具有重要意义。
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引用次数: 0
Stress analysis of an inclusion layer bonded to an irregularly shaped pore under an edge dislocation or a concentrated load 边缘位错或集中载荷作用下与不规则孔结合的夹杂物层应力分析
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac028
Y. Liao, S. Tseng, C. Chao
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.
气孔在金属铸件的失效分析中起着重要的作用。在凝固过程中,气孔周围可能形成氧化物、氮化物和硫化物等渣夹杂物。本文给出了在边缘位错或集中载荷作用下与方孔结合的夹杂层的解析解。基于映射法和解析延拓定理,得到了滑移力和爬升力以及位错或集中荷载引起的界面应力的封闭形式。结果表明,形状因子较大(或较小)的夹杂层会在界面附近(或远处)形成稳定的平衡位置。当形状因子减小时,随着夹杂层刚度的增大,稳定平衡位置远离界面。在集中载荷下,界面应力随弹性失配和边角锐度的增大而增大。这些发现可以改善冶金制造系统中基体与夹杂层之间的相容性。
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引用次数: 1
Support motion of a finite bar with a viscously damped boundary 具有粘性阻尼边界的有限杆的支承运动
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac035
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.
本文将以往的经验推广到具有粘滞阻尼边界和另一侧支承运动的有限杆的振动问题。采用模态叠加法结合准静态分解法和基于特征法的金刚石规则法两种解析方法,推导出两种解析解。一种是用模态叠加法求级数解。另一种是用菱形法则求精确解。采用金刚石法则的方法直接求解了带有外阻尼器的非保守系统,避免了复值本征系统。协议达成得很好。讨论了两种方法的优缺点。
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引用次数: 0
The field of applied mechanics: historical outlook from past to present and its implications for future applications 应用力学领域:从过去到现在的历史展望及其对未来应用的启示
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac042
Chih-Kung Lee
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.
本文的重点是回顾应用力学领域从过去到现在的发展。从历史的角度来看,我们可以更好地理解应用力学领域在我们社会中的重要贡献和成就。本文将首先回顾应用力学在过去400年的历史,然后看看19世纪和20世纪的工程教育,然后检查应用力学在当今社会的演变。我们将讨论当今应用力学中一些跨学科的发展,如铁磁材料在强磁场中的屈曲,基于力学的纳米尺度测量仪器,射频微电子系统,生物芯片和纳米技术。最后,我们将通过马斯洛的人类需求五层次理论来总结,并提供几个创新的例子,以进一步实施应用力学研究的创新模型,以在当今以人工智能和信息技术为基础的社会中教授更先进的知识。
{"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":null,"pages":null},"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}
引用次数: 0
Miscible fluids mixing via alternating injection in a radial Hele-Shaw cell: experimental and numerical studies 在径向Hele-Shaw槽中通过交替注射混合混相流体:实验和数值研究
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac043
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.
采用交替注入方案对径向Hele-Shaw槽内混相粘性流体的混合性能进行了实验研究。引入覆盖面积的概念来量化混合效率,并进行了各种数值模拟来支持和验证实验结果。已经观察到交替注入可以提高混合效率,这取决于通道相互作用的突出程度。在扩散混合为主、指法作用较弱的特定条件下,交替注入能有效提高混合效率。然而,高psamclet数条件下的结果并不一致,即由于出现有序的粘性手指而导致随机混沌相互作用,从而降低了混合效率。这种现象类似于非均质渗透率场中的通道相互作用,其中粘性较小的流体由于两个连续出现的手指之间的局部压力差而通过有利的路径流动。
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引用次数: 1
Quadrilateral layout generation and optimization using equivalence classes of integral curves: theory and application to surfaces with boundaries 利用积分曲线的等价类生成和优化四边形布局:有边界曲面的理论和应用
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac002
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.
从表面三角形中提取四边形布局是纹理映射、传统分析中的半结构四边形网格划分和等几何分析中的样条重构的重要步骤。目前的方法很难产生高质量的布局,在奇异节点之间具有适当的连通性(对于样条表示称为“异常点”),而不诉诸混合整数优化或手动约束处方。第一种方法在计算上很昂贵,而且没有保证,而第二种方法很费力,而且容易出错。在这项工作中,我们严格描述了四边形布局中的曲线直至同伦类型,并使用该信息快速定义奇异节点之间的高质量连接约束。数学理论伴随着适当的计算算法。在美国陆军DEVCOM通用车体车辆和1996年道奇霓虹灯双线性四边形有限元网格(带有一些线性三角形)的部分上,证明了所提出方法的有效性。
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引用次数: 6
Dynamic response of slender body passing through ice and water mixture at high velocity 细长体高速通过冰与水混合物的动力响应
IF 1.7 4区 工程技术 Q2 Mathematics Pub Date : 2022-01-01 DOI: 10.1093/jom/ufac016
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.
在水下运动过程中,由于复杂的水下环境和空化效应,弹丸的弹道会受到很大的干扰。为了研究冰水混合物对弹丸运动的影响,本文采用一级轻气枪装填系统、超压传感器测量系统和高速摄像机采集系统,进行了截断锥形平板战斗部钛合金细长体穿过冰水混合物的实验。实验结果表明,长径比较小的细长体产生的空腔体积较大,且细长体在运动过程中发生偏转。对于长径比大的细长体,形成的空腔更靠近中心轴线和最大径向尺寸。无论战斗部形状是截锥形战斗部还是平板战斗部,空腔直径和持续时间都随着细长体速度的增加而增加。在长径比和细长体速度相似的条件下,两种细长体产生的超压总体演化趋势相似。但平板战斗部超压幅值波动幅度较小,相邻时间曲线振荡幅值较大,截锥形战斗部超压峰值较大。在相同的长径比下,速度对细长体撞击冰粒后的运动轨迹没有明显影响。细长体与冰粒碰撞时,其轨迹偏转角度大于撞击冰粒边缘的偏转角度。细长体与冰粒碰撞时,冰粒与细长体的相互作用较大,细长体撞击后的偏转角度较大。
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引用次数: 0
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Journal of Mechanics
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