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Nano reinforcement technique as a tool for enhancement the mechanical and fatigue properties 纳米增强技术作为一种提高机械和疲劳性能的工具
IF 1.5 Q4 MECHANICS Pub Date : 2022-01-01 DOI: 10.1515/cls-2022-0026
Abdulwahab M. Al-Mushehdany, M. Yahya, Esraa Kadhim Ibrahim, H. J. Alalkawi
Abstract For the past three decades, AA7075 based metal matrix composite materials showed more attraction due to their enhanced mechanical and fatigue properties. The mechanical and fatigue behaviour of nano composites needs more investigation for their applications. In the present study, stir casting route based AA7075 reinforced with nano – sized, Al2O3 particles (average size 35 nm). The evaluation of mechanical and fatigue properties in the nano cast composites and matrix were carried out at room temperature (RT). The composites and base metalwere subjected to high and low cycle fatigue. Scanning Electron Microscope was used to estimate fatigue behaviour of nano composites samples. The mechanical and fatigue properties was enhanced by the nano Al2O3, when compared to the matrix. The microsite evaluation showed uniform distribution of Al2O3 particles into the matrix and few porosity was recorded. The improvement of the properties above is attributed to the grain refinement and to the distribution of the Al2O3.
在过去的三十年里,AA7075基金属基复合材料因其优异的力学性能和疲劳性能而受到越来越多的关注。纳米复合材料的力学性能和疲劳性能有待进一步研究。本研究采用搅拌浇铸法制备了纳米Al2O3增强AA7075(平均尺寸为35 nm)。在室温下对纳米铸造复合材料和基体的力学性能和疲劳性能进行了评价。对复合材料和母材进行了高、低周疲劳试验。利用扫描电镜对纳米复合材料试样的疲劳行为进行了表征。与基体相比,纳米Al2O3增强了材料的力学性能和疲劳性能。显微形貌分析表明,Al2O3颗粒在基体中分布均匀,孔隙率较低。上述性能的改善与晶粒细化和Al2O3的分布有关。
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引用次数: 3
Bow structure damage analysis for hybrid coir-glass fiber composite fishing boat hull subjected to front collision load 前碰撞载荷作用下混杂型椰壳-玻璃纤维复合材料渔船船体船头结构损伤分析
IF 1.5 Q4 MECHANICS Pub Date : 2022-01-01 DOI: 10.1515/cls-2022-0020
A. Windyandari, O. Kurdi, Sulardjaka, M. Tauviqirrahman
Abstract Hybridization of natural and synthetic fibers has the ability to improve composite performance. It means that the combination of natural fibers such as coir, jute, bamboo, and sisal with synthetic or glass fiber can broaden the role of the composite material, especially for structural application. This study developed a finite element simulation to investigate the damage to the bow structure of the fishing boat hull, which was produced using hybrid coir-glass fiber composite (HCGFRP) material subjected to front collision load. The experimental measurement was conducted to determine the mechanical properties of four hybrid composite laminates defined based on the differences in their layers number, fiber types, and orientation angle. Moreover, a numerical simulation model was applied to the traditional fishing boat colliding with fishery harbor quay, and the scenario was defined by varying the boat speed and the types of laminates adopted on the hull structure. The results showed the damage level for the bow structure of the HCGFRP boat due to the collision accidents, while the numerical findings are expected to be used as the basic knowledge in applying the hybrid coir-glass fiber laminates composite as an alternative hull construction material.
摘要天然纤维与合成纤维的杂交具有提高复合材料性能的能力。它的意思是,将椰子、黄麻、竹、剑麻等天然纤维与合成纤维或玻璃纤维相结合,可以拓宽复合材料的作用,特别是在结构应用方面。本研究采用有限元模拟方法研究了采用混合椰壳-玻璃纤维复合材料(HCGFRP)制造的渔船船体艏部结构在正面碰撞载荷作用下的损伤。基于层数、纤维类型和取向角的不同,对四种混杂复合材料层合板的力学性能进行了实验测量。建立了传统渔船与渔港码头碰撞的数值模拟模型,通过改变船速和船体结构上采用的层压板类型来定义碰撞场景。研究结果显示了HCGFRP船首结构在碰撞事故下的损伤程度,同时数值研究结果有望为将混合纤维-玻璃纤维复合材料作为替代船体结构材料的应用提供基础知识。
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引用次数: 1
Thermal fatigue analysis of different nano coating thickness by air plasma spraying in diesel engine thermal barrier coating 空气等离子喷涂柴油机热障涂层不同厚度纳米涂层的热疲劳分析
IF 1.5 Q4 MECHANICS Pub Date : 2022-01-01 DOI: 10.1515/cls-2022-0028
Q. Mahdi, Ibtihal A. Mhmood, Mahmoud A Mashhour
Abstract The use of Atmospheric Plasma Spraying (APS) and yttria stabilized zirconia (YSZ) nanostructured coatings has been applied to the bond layer of NiCrAlY coated engine cylinder heads, pistons, and valve substrates. Thermal barrier coatings (TBCs) have been utilized to increase the engine performance in the design of combustion chamber components for internal combustion engines. ASTM-C-633-01 standard has been employed to conduct the bonding strength testing. It was also considered and directed to estimate the coating’s thermal performance by evaluating its insulation value and conducting a thermal insulation durability assessment. Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were used to look at the nano powders and coatings’ microstructures and phase compositions. In YSZ, it was discovered that the topcoat of samples had a tri-modal pattern of nano sized particles engaged by the powder, micro-columnar grains generated from the re-solidification of the molten part of the powder, and almost equiaxed grains, which were a unique construction feature. The results demonstrated the creation of nano zones in one of three nanostructured coating zones and improved the top coating properties, including bonding strength and thermal insulation capacity. The high temperature of the diesel engine caused fatigue failure in the intake and exhaust valves.
利用大气等离子喷涂(APS)和氧化钇稳定氧化锆(YSZ)纳米结构涂层,应用于NiCrAlY涂层发动机缸盖、活塞和气门基板的结合层。在内燃机燃烧室部件的设计中,热障涂层已被用于提高发动机的性能。结合强度试验采用ASTM-C-633-01标准进行。还考虑并指导通过评估其隔热值和进行隔热耐久性评估来评估涂层的热性能。采用场发射扫描电镜(FESEM)和x射线衍射仪(XRD)观察了纳米粉末和涂层的微观结构和相组成。在YSZ中发现,样品的面涂层具有三模态模式:纳米颗粒与粉末的接合,粉末熔融部分再凝固产生的微柱状晶粒,以及几乎等轴的晶粒,这是一种独特的结构特征。结果表明,在三个纳米结构涂层区中,有一个形成了纳米区,并改善了涂层的表面性能,包括结合强度和保温能力。柴油机的高温导致进排气气阀疲劳失效。
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引用次数: 1
Size-dependent nonlinear vibration analysis of nanobeam embedded in multi-layer elastic media and subjected to electromechanical and thermomagnetic loadings 嵌入多层弹性介质中的纳米梁在机电和热磁载荷作用下的尺寸相关非线性振动分析
IF 1.5 Q4 MECHANICS Pub Date : 2022-01-01 DOI: 10.1515/cls-2022-0031
G. Sobamowo
Abstract In this work, magneto-electro-mechanical size-dependent nonlinear vibration analysis of nanobeam embedded in multi-layer of Winkler, Pasternak, quadratic and cubic nonlinear elastic media is presented. A nonlinear partial differential equation of motion is derived using Von Karman geometric nonlinearity, nonlocal elasticity theory, Euler-Bernoulli beam theory and Hamilton’s principle. Additionally, the efficiency of multiple scales Lindstedt-Poincare method for the strong nonlinear and large amplitude systems is presented. It is established that the results of multiple scales Lindstedt-Poincare method are in good agreements with the numerical and exact solutions for the strong nonlinear problems. However, the classical multiple scales method fails and gives results with very large discrepancies form the results of the numerical and exact solutions when the perturbation parameter is large, and the nonlinearity terms are strong. The high accuracy of the results of multiple scales Lindstedt-Poincare method and its excellent ability to produce accurate results for all values (small and large) of perturbation parameter and the nonlinearity terms show the superiority of the multiple scales Lindstedt-Poincare method over the classical multiple scales method. Further results present the effects of the model parameters on the dynamic behaviour of the nanobeam. It is hoped that the present study will advance nonlinear analysis of the engineering structures.
摘要本文对嵌入多层Winkler、Pasternak、二次和三次非线性弹性介质中的纳米梁进行了与机电尺寸相关的非线性振动分析。利用Von-Karman几何非线性、非局部弹性理论、Euler-Bernoulli梁理论和Hamilton原理,导出了一个非线性偏微分运动方程。此外,给出了强非线性大振幅系统的多尺度Lindsted-Poincare方法的有效性。证明了多尺度Lindsted-Poincare方法的结果与强非线性问题的数值解和精确解是一致的。然而,当扰动参数较大且非线性项较强时,经典的多尺度方法失败了,并且给出的结果与数值解和精确解的结果有很大的差异。多尺度Lindsted-Poincare方法的结果具有较高的精度,并且能够对扰动参数和非线性项的所有值(小值和大值)产生精确的结果,这表明了多尺度Lindsdt-Poincare法优于经典的多尺度方法。进一步的结果显示了模型参数对纳米束动态行为的影响。希望本文的研究能进一步推动工程结构的非线性分析。
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引用次数: 0
Experimental and analytical study on the behavior of hybrid GFRP/steel bars in reinforced concrete deep beams 钢筋混凝土深梁中GFRP/钢筋混合性能的试验与分析研究
IF 1.5 Q4 MECHANICS Pub Date : 2022-01-01 DOI: 10.1515/cls-2022-0012
A. Shoeib, Ahmed Arafa, Ramy Abd El-Hakeem Abd El Rady, W. Tawhed
Abstract The deep beam is one of the essential members of high-rise buildings structures, so the deep beams are used as a transfer girder; in walls water structures, the deep beam behavior is different from the slender beam behavior; the deep beam plane section before does not remain plane after bending. In recent years, the use of FRP as a composite material in reinforced concrete structures has been growing up to cover problems by weight of structure buildings, corrosion, repairing, and construction cost. This paper presents an experimental, analytical study to assign the variation of mechanical properties of reinforced concrete deep beams using vertical and horizontal GFRP stirrups. This paper investigates the mechanical properties of test specimens for deep beams reinforced in shear with GFRP or steel bars as web reinforcement. The deep beams are reinforced with glass fiber reinforced polymer (GFRP) in various ratios as a web reinforcement configuration (0, 0.25%, and 0.40%) rather than traditional steel web reinforcement. All tested specimens have the same span to depth ratio of 0.40 (a/d); the primary and secondary reinforcement is steel bars. The web reinforcement ratio significantly affected deep beams’ load capacity and mechanical behavior. The GFRP enhancement the mechanical behavior of the reinforced concrete deep. Increasing the GFRP web reinforcement ratio enhances the deep beam load capacity. The test results compared with the traditional ACI design method strut-tie model to demonstrate the effect of web reinforcement ratio on deep beam load capacity and strut width. The test results have been verified by ABAQUS 6.13.
摘要深梁是高层建筑结构的重要构件之一,因此深梁被用作转换梁;在墙-水结构中,深梁的受力性能不同于细梁;弯曲之前的深梁平面部分在弯曲之后不保持平面。近年来,FRP作为一种复合材料在钢筋混凝土结构中的应用越来越多,以解决结构建筑重量、腐蚀、修复和施工成本等问题。本文对使用垂直和水平GFRP箍筋的钢筋混凝土深梁的力学性能变化进行了实验分析研究。本文研究了以GFRP或钢筋作为腹板钢筋的受剪深梁试件的力学性能。深梁采用不同比例的玻璃纤维增强聚合物(GFRP)作为腹板钢筋配置(0、0.25%和0.40%)进行加固,而不是传统的钢腹板钢筋。所有试样的跨度与深度之比相同,为0.40(a/d);主筋和次筋均为钢筋。腹板配筋率对深梁的承载力和力学性能有显著影响。GFRP增强了钢筋混凝土深层的力学性能。增加GFRP腹板配筋率可以提高深梁的承载能力。试验结果与传统ACI设计方法的压杆-拉结模型进行了比较,验证了腹板配筋率对深梁承载力和压杆宽度的影响。测试结果已通过ABAQUS 6.13进行验证。
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引用次数: 2
Effect of concrete and reinforcement continuity on repairing mid-span zone in simply supported one-way slab 混凝土与钢筋连续性对单向简支板跨中区修复的影响
IF 1.5 Q4 MECHANICS Pub Date : 2021-12-04 DOI: 10.1515/cls-2022-0006
M. J. Kadhim, K. Shadhan, Bilal Ismaeel Abd Al-Zahra
Abstract The flexural strength of slabs may be reduced due to accidents and environmental effects. This study focuses on the rehabilitation of the one-way reinforced concrete slab. Experimental works include five simply supported one-way reinforced concrete slabs with width, depth, and length of 400, 120, and 2200 mm, respectively. Different configurations of steel continuity between old and new concrete have been tested. Moreover, in the control specimen (steel is continued overall, the specimen and concrete are cast in one stage over the entire slab). In the other four specimens, the concrete is cast in two stages, the left and right parts representing the old concrete are cast first, and the middle part representing a new concrete is cast after that. In these four specimens, new steel is connected to old one by different configuration (original steel remain to continue, new steel connected to old one by weld, new steel connected to old one by making 90° hooks, and new steel bars is put inside bores using epoxy). After testing, the welding method of connecting new to old steel is the best one.
摘要板的抗弯强度可能由于事故和环境影响而降低。本研究的重点是单向钢筋混凝土板的修复。实验工程包括五块宽度、深度和长度分别为400、120和2200 mm的单向简支钢筋混凝土板。已经测试了新旧混凝土之间钢连续性的不同配置。此外,在对照试件中(钢总体上是连续的,试件和混凝土在一个阶段浇筑在整个板上)。在其他四个试样中,混凝土分两个阶段浇筑,首先浇筑代表旧混凝土的左右部分,然后浇筑代表新混凝土的中间部分。在这四个试件中,新钢通过不同的配置与旧钢连接(原始钢保持连续,新钢与旧钢通过焊接连接,新钢和旧钢通过制作90°弯钩连接,新钢筋使用环氧树脂放入孔内)。经测试,新旧钢材连接的焊接方法是最佳的焊接方法。
{"title":"Effect of concrete and reinforcement continuity on repairing mid-span zone in simply supported one-way slab","authors":"M. J. Kadhim, K. Shadhan, Bilal Ismaeel Abd Al-Zahra","doi":"10.1515/cls-2022-0006","DOIUrl":"https://doi.org/10.1515/cls-2022-0006","url":null,"abstract":"Abstract The flexural strength of slabs may be reduced due to accidents and environmental effects. This study focuses on the rehabilitation of the one-way reinforced concrete slab. Experimental works include five simply supported one-way reinforced concrete slabs with width, depth, and length of 400, 120, and 2200 mm, respectively. Different configurations of steel continuity between old and new concrete have been tested. Moreover, in the control specimen (steel is continued overall, the specimen and concrete are cast in one stage over the entire slab). In the other four specimens, the concrete is cast in two stages, the left and right parts representing the old concrete are cast first, and the middle part representing a new concrete is cast after that. In these four specimens, new steel is connected to old one by different configuration (original steel remain to continue, new steel connected to old one by weld, new steel connected to old one by making 90° hooks, and new steel bars is put inside bores using epoxy). After testing, the welding method of connecting new to old steel is the best one.","PeriodicalId":44435,"journal":{"name":"Curved and Layered Structures","volume":"9 1","pages":"65 - 71"},"PeriodicalIF":1.5,"publicationDate":"2021-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47167805","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}
引用次数: 0
Numerical evaluation of expansion loops for pipe subjected to thermal displacements 热位移作用下管道膨胀回路的数值计算
IF 1.5 Q4 MECHANICS Pub Date : 2021-12-04 DOI: 10.1515/cls-2022-0007
H. Yudo, S. Jokosisworo, Wilma Amiruddin, Pujianto Pujianto, T. Tuswan, M. Djaeni
Abstract The thermal expansion can lead to the high stress on the pipe. The problem can be overcome using expansion loops in a certain length depending on the material’s elastic modulus, diameter, the amount of expansion, and the pipe’s allowable stresses. Currently, there is no exact definition for the dimension of expansion loops design both for loop width (W) and loop footing height (H) sizes. In this study, expansion loops were investigated with using ratio of width and height (W/H) variations to understand pipe stress occurring on the expansion loops and the expansion loops’ safety factor. Relationship between non dimensional stress on the expansion loop pipe was studied numerically by finite element software on several working temperatures of 400oF, 500oF, 600oF, and 700oF. It can be found that stress occurring on the pipes increases as the increases of W/H of the expansion loops and results in a lower safety factor. The safety factor of the expansion loops pipe has a value of 1 when the ratio of loop width and loop footing height (W/H) value was 1.2 for a 16-inch diameter pipe. Stress occurring on the pipe increases with the increase of the working temperature. Expansion loops pipe designed for 400oF can still work well to handle thermal extension pipe occurring on 500oF.
摘要热膨胀会导致管道上的高应力。根据材料的弹性模量、直径、膨胀量和管道的许用应力,使用一定长度的膨胀环可以解决这个问题。目前,对于环路宽度(W)和环路基脚高度(H)的尺寸,膨胀环路设计的尺寸没有确切的定义。在本研究中,利用宽高比(W/H)变化对膨胀环进行了研究,以了解膨胀环上发生的管道应力和膨胀环的安全系数。利用有限元软件,在400oF、500oF、600oF和700oF的几个工作温度下,对膨胀环管上的无量纲应力之间的关系进行了数值研究。可以发现,管道上产生的应力随着膨胀环W/H的增加而增加,并导致较低的安全系数。对于直径为16英寸的管道,当回路宽度和回路基脚高度(W/H)的比值为1.2时,膨胀回路管道的安全系数为1。管道上产生的应力随着工作温度的升高而增加。设计用于400华氏度的膨胀环管仍然可以很好地处理500华氏度的热膨胀管。
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引用次数: 0
Application of generalized equations of finite difference method to computation of bent isotropic stretched and/or compressed plates of variable stiffness under elastic foundation 广义有限差分法在弹性基础下各向同性变刚度拉伸板计算中的应用
IF 1.5 Q4 MECHANICS Pub Date : 2021-11-06 DOI: 10.1515/cls-2022-0005
Seydou Youssoufa, Moussa Sali, A. Njifenjou, Nkongho Anyi Joseph, Ngayihi Abbe Claude Valery
Abstract The computation of bent isotropic plates, stretched and/or compressed, is a topic widely explored in the literature from both experimental and numerical point of view. We expose in this work an application of the generalized equations of Finite difference method to that topic. The strength of the proposed method is the ability to reconstruct the approximate solution with respect of eventual discontinuities involved in the investigated function as well as its first and second derivatives, including the right-hand side of the equilibrium equation. It is worth mentioning that by opposition to finite element methods our method needs neither fictitious points nor a special condensation of grid. Well-known benchmarks are used in this work to illustrate the efficiency of our numerical and the high accuracy of calculation as well. A comparison of our results with those available in the literature also shows good agreement.
摘要从实验和数值的角度来看,弯曲各向同性板(拉伸和/或压缩)的计算是文献中广泛探讨的一个话题。在这项工作中,我们揭示了有限差分法的广义方程在该主题中的应用。所提出的方法的优点是能够重建所研究函数及其一阶和二阶导数(包括平衡方程的右侧)中涉及的最终不连续性的近似解。值得一提的是,与有限元方法相反,我们的方法既不需要虚设点,也不需要网格的特殊凝聚。在这项工作中使用了众所周知的基准来说明我们的数值计算的效率和高精度。将我们的结果与文献中的结果进行比较也显示出良好的一致性。
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引用次数: 0
Application of physical theory of cavity in the construction of double skin facades 空腔物理理论在双层外墙施工中的应用
IF 1.5 Q4 MECHANICS Pub Date : 2021-11-03 DOI: 10.1515/cls-2022-0004
B. Bielek, D. Szabó, J. Klem, Kristína Kaniková
Abstract The article deals with the issue of double skin transparent facades as a new technological-operational system of transparent exterior walls. Especially of high-rise buildings, which with its operating modes ingeniously uses a renewable source of solar energy to reduce the energy needs of the building. The basic precondition for the correct function of the double skin facade is its functional aerodynamics in any climatic conditions of the outdoor climate. In the critical state of windlessness, the aerodynamic quantification of a double skin facade is the total aerodynamic resistance of the cavity, which consists of the aerodynamic frictional resistances along the length of the air flow line and local aerodynamic resistances of the cavity. The article analyses the functional aerodynamics on two frequented types of double skin facades with a narrow type and corridor type cavity. At the end it confronts functional aerodynamics with the results of their temperature, aerodynamic and energy regime obtained from in-situ experiments.
摘要本文论述了双层透明外墙作为一种新的透明外墙技术操作系统的问题。尤其是高层建筑,其运行模式巧妙地使用了可再生太阳能来减少建筑的能源需求。双层外墙正确发挥功能的基本前提是其在室外气候的任何气候条件下的功能空气动力学。在无风的临界状态下,双层表皮立面的气动量化是空腔的总气动阻力,它包括沿空气流线长度的气动摩擦阻力和空腔的局部气动阻力。本文分析了两种常见类型的窄型和走廊型双层外墙的功能空气动力学。最后,通过现场实验获得了功能空气动力学的温度、空气动力学和能量状态的结果。
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引用次数: 0
On the deformation of laminated composite and sandwich curved beams 层合复合材料与夹层弯曲梁的变形研究
IF 1.5 Q4 MECHANICS Pub Date : 2021-10-18 DOI: 10.1515/cls-2022-0001
P. V. Avhad, A. S. Sayyad
Abstract Plenty of research articles are available on the static deformation analysis of laminated straight beams using refined shear deformation theories. However, research on the deformation of laminated curved beams with simply supported boundary conditions is limited and needs more attention nowadays. With this objective, the present study deals with the static analysis of laminated composite and sandwich beams curved in elevation using a new quasi-3D polynomial type beam theory. The theory considers the effects of both transverse shear and normal strains, i.e. thickness stretching effects. In the present theory, axial displacement has expanded up to the fifth-order polynomial in terms of thickness coordinates to effectively account for the effects of curvature and deformations. The present theory satisfies the zero traction boundary condition on the top and bottom surfaces of the beam. Governing differential equations and associated boundary conditions are established by using the Principal of virtual work. Navier’s solution technique is used to obtain displacements and stresses for simply supported beams curved in elevation and subjected to uniformly distributed load. The present results can be benefited to the upcoming researchers.
摘要利用精细的剪切变形理论,对叠层直梁的静力变形进行了分析,已有大量的研究文章。然而,目前对具有简支边界条件的叠层曲梁变形的研究是有限的,需要更多的关注。为此,本研究采用一种新的准三维多项式型梁理论,对立面弯曲的叠层复合材料梁和夹层梁进行了静力分析。该理论考虑了横向剪切和法向应变的影响,即厚度拉伸效应。在目前的理论中,轴向位移已经扩展到厚度坐标的五阶多项式,以有效地考虑曲率和变形的影响。该理论满足梁上下表面的零牵引边界条件。利用虚功原理建立了控制微分方程及其边界条件。Navier的求解技术用于获得在高程上弯曲并受到均匀分布载荷的简支梁的位移和应力。目前的研究结果可以为即将到来的研究人员带来好处。
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引用次数: 4
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Curved and Layered Structures
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