资源类型

期刊论文 145

年份

2023 20

2022 9

2021 7

2020 11

2019 11

2018 6

2017 11

2016 9

2015 4

2014 2

2013 8

2012 4

2011 9

2010 1

2009 8

2008 6

2007 2

2006 1

2005 1

2004 4

展开 ︾

关键词

优化设计 2

增材制造 2

机械结构 2

湍流边界层 2

疲劳寿命 2

直接数值模拟 2

3D打印 1

3D生物打印 1

DNA结构 1

EBL 1

FIB 1

ICP 1

三峡 1

三索面空间结构 1

三维含孔洞结构 1

不经意传输;后量子;格公钥;带差错学习;通用可复合 1

中国台湾 1

中高频响应 1

五模材料 1

展开 ︾

检索范围:

排序: 展示方式:

Robust topology optimization of multi-material lattice structures under material and load uncertainties

Yu-Chin CHAN, Kohei SHINTANI, Wei CHEN

《机械工程前沿(英文)》 2019年 第14卷 第2期   页码 141-152 doi: 10.1007/s11465-019-0531-4

摘要: Enabled by advancements in multi-material additive manufacturing, lightweight lattice structures consisting of networks of periodic unit cells have gained popularity due to their extraordinary performance and wide array of functions. This work proposes a density-based robust topology optimization method for meso- or macro-scale multi-material lattice structures under any combination of material and load uncertainties. The method utilizes a new generalized material interpolation scheme for an arbitrary number of materials, and employs univariate dimension reduction and Gauss-type quadrature to quantify and propagate uncertainty. By formulating the objective function as a weighted sum of the mean and standard deviation of compliance, the tradeoff between optimality and robustness can be studied and controlled. Examples of a cantilever beam lattice structure under various material and load uncertainty cases exhibit the efficiency and flexibility of the approach. The accuracy of univariate dimension reduction is validated by comparing the results to the Monte Carlo approach.

关键词: robust topology optimization     lattice structures     multi-material     material uncertainty     load uncertainty     univariate dimension reduction    

Compressive behavior and energy absorption of polymeric lattice structures made by additive manufacturing

Sheng WANG, Jun WANG, Yingjie XU, Weihong ZHANG, Jihong ZHU

《机械工程前沿(英文)》 2020年 第15卷 第2期   页码 319-327 doi: 10.1007/s11465-019-0549-7

摘要: Lattice structures have numerous outstanding characteristics, such as light weight, high strength, excellent shock resistance, and highly efficient heat dissipation. In this work, by combining experimental and numerical methods, we investigate the compressive behavior and energy absorption of lattices made through the stereolithography apparatus process. Four types of lattice structures are considered: (i) Uniform body-centered-cubic (U-BCC); (ii) graded body-centered-cubic (G-BCC); (iii) uniform body-centered-cubic with -axis reinforcement (U-BCCz); and (iv) graded body-centered-cubic with -axis reinforcement (G-BCCz). We conduct compressive tests on these four lattices and numerically simulate the compression process through the finite element method. Analysis results show that BCCz has higher modulus and strength than BCC. In addition, uniform lattices show better energy absorption capabilities at small compression distances, while graded lattices absorb more energy at large compression distances. The good correlation between the simulation results and the experimental phenomena demonstrates the validity and accuracy of the present investigation method.

关键词: lattice structure     polymer     compressive behavior     additive manufacturing     simulation    

Design and applications of morphing aircraft and their structures

《机械工程前沿(英文)》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0750-6

摘要: Morphing aircraft can adaptively regulate their aerodynamic layout to meet the demands of varying flight conditions, improve their aerodynamic efficiency, and reduce their energy consumption. The design and fabrication of high-performance, lightweight, and intelligent morphing structures have become a hot topic in advanced aircraft design. This paper discusses morphing aircraft development history, structural characteristics, existing applications, and future prospects. First, some conventional mechanical morphing aircraft are examined with focus on their morphing modes, mechanisms, advantages, and disadvantages. Second, the novel applications of several technologies for morphing unmanned aerial vehicles, including additive manufacturing for fabricating complex morphing structures, lattice technology for reducing structural weight, and multi-mode morphing combined with flexible skins and foldable structures, are summarized and categorized. Moreover, in consideration of the further development of active morphing aircraft, the paper reviews morphing structures driven by smart material actuators, such as shape memory alloy and macro-fiber composites, and analyzes their advantages and limitations. Third, the paper discusses multiple challenges, including flexible structures, flexible skins, and control systems, in the design of future morphing aircraft. Lastly, the development and application of morphing structures in the aerospace field are discussed to provide a reference for future research and engineering applications.

关键词: morphing aircraft     additive manufacturing     lattice structure     smart material     flexible structure     flexible skin    

Uncertainty of concrete strength in shear and flexural behavior of beams using lattice modeling

《结构与土木工程前沿(英文)》 2023年 第17卷 第2期   页码 306-325 doi: 10.1007/s11709-022-0890-5

摘要: This paper numerically studied the effect of uncertainty and random distribution of concrete strength in beams failing in shear and flexure using lattice modeling, which is suitable for statistical analysis. The independent variables of this study included the level of strength reduction and the number of members with reduced strength. Three levels of material deficiency (i.e., 10%, 20%, 30%) were randomly introduced to 5%, 10%, 15%, and 20% of members. To provide a database and reliable results, 1000 analyses were carried out (a total of 24000 analyses) using the MATLAB software for each combination. Comparative studies were conducted for both shear- and flexure-deficit beams under four-point loading and results were compared using finite element software where relevant. Capability of lattice modeling was highlighted as an efficient tool to account for uncertainty in statistical studies. Results showed that the number of deficient members had a more significant effect on beam capacity compared to the level of strength deficiency. The scatter of random load-capacities was higher in flexure (range: 0.680–0.990) than that of shear (range: 0.795–0.996). Finally, nonlinear regression relationships were established with coefficient of correlation values (R2) above 0.90, which captured the overall load–deflection response and level of load reduction.

关键词: lattice modeling     shear failure     flexural failure     uncertainty     deficiency     numerical simulation    

Simulation of interfacial Marangoni convection in gas-liquid mass transfer by lattice Boltzmann method

Shuyong CHEN, Xigang YUAN, Bo FU, Kuotsung YU

《化学科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 448-454 doi: 10.1007/s11705-011-1142-8

摘要: Interfacial Marangoni convection has significant effect on gas-liquid and/or liquid-liquid mass transfer processes. In this paper, an approach based on lattice Boltzmann method is established and two perturbation models, fixed perturbation model and self-renewable interface model, are proposed for the simulation of interfacial Marangoni convection in gas-liquid mass transfer process. The simulation results show that the concentration contours are well consistent with the typical roll cell convection patterns obtained experimentally in previous studies.

关键词: interfacial Marangoni convection     lattice Boltzmann method     gas-liquid mass transfer    

slip investigation based on finite element modelling verified by experimental results on wind turbine lattice

Saleh YAGHOOBI, Ahmad SHOOSHTARI

《结构与土木工程前沿(英文)》 2018年 第12卷 第3期   页码 341-351 doi: 10.1007/s11709-017-0393-y

摘要:

Slippage corresponds to the relative displacement of a bolted joint subjected to shear loads since the construction clearance between the bolt shank and the bolthole at assembly can cause joint slip. Deflections of towers with joint slippage effects is up to 1.9 times greater than the displacements obtained by linear analytical methods. In this study, 8 different types of joints are modelled and studied in the finite element program, and the results are verified by the experimental results which have been done in the laboratory. Moreover, several types of joints have been modelled and studied and load-deformation curves have also been presented. Finally, joint slip data for different types of angles, bolt diameter and bolt arrangements are generated. Thereupon, damping ratios (z) for different types of connections are reported. The study can be useful to help in designing of wind turbine towers with a higher level of accuracy and safety.

关键词: Joint slip     cyclic loading     Finite element modelling     Experimental joint behavior     damping ratios (   

URANS simulation of the turbulent flow in tight lattice bundle

Yiqi YU, Yanhua YANG

《能源前沿(英文)》 2011年 第5卷 第4期   页码 404-411 doi: 10.1007/s11708-011-0165-7

摘要: The flow structure in tight lattice is still of great interest to nuclear industry. An accurate prediction of flow parameter in subchannels of tight lattice is likable. Unsteady Reynolds averaged Navier Stokes (URANS) is a promising approach to achieve this goal. The implementation of URANS approach will be validated by comparing computational results with the experimental data of Krauss. In this paper, the turbulent flow with different Reynolds number (5000–215000) and different pitch-to-diameter( / ) (1.005–1.2) are simulated with computational fluid dynamics (CFD) code CFX12. The effects of the Reynolds number and the bundle geometry ( / ) on wall shear stress, turbulent kinetic energy, turbulent mixing and large scale coherent structure in tight lattice are analyzed in details. It is hoped that the present work will contribute to the understanding of these important flow phenomena and facilitate the prediction and design of rod bundles.

关键词: tight rod bundle     flow structure     unsteady Reynolds averaged Navier Stokes (URANS)    

超轻折叠夹层圆柱壳的制备及力学性能测试 Article

李万欣, 郑青, 范华林, 冀宾

《工程(英文)》 2020年 第6卷 第2期   页码 196-204 doi: 10.1016/j.eng.2019.11.008

摘要:

在本研究中,我们设计、制备和测试了两种新型折叠夹层圆柱壳。格栅夹芯具有周期性的“之”字形波纹,其脊线与谷线沿着轴向或环向延伸。通过自由振动和轴向压缩试验,我们研究了圆柱壳的固有频率、自由振动模态、承载能力和失效模式。通过减小局部蒙皮周期单元的尺寸,折叠格栅夹芯能有效地抑制折叠夹层圆柱壳的局部屈曲;通过提高夹层的剪切刚度,折叠格栅夹芯能有效地提高折叠夹层圆柱壳整体的抗屈曲性能。圆柱壳在材料失效模式下失效,其具有良好的承载能力。轴向折叠夹层圆柱壳具有更高的承载能力,而环向折叠夹层圆柱壳具有更高的固有频率。这两种折叠格栅内芯为工程师设计有强度或振动要求的夹层圆柱壳提供了一种选择。本研究也为大尺寸折叠结构的制作和工程应用提供了一种可行的方法。

关键词: 折叠夹层圆柱壳     制备     力学试验    

Soil arching effect of Lattice-Shaped Diaphragm Wall as bridge foundation

Jiujiang WU, Lingjuan WANG, Qiangong CHENG

《结构与土木工程前沿(英文)》 2017年 第11卷 第4期   页码 446-454 doi: 10.1007/s11709-017-0397-7

摘要: As a new type of bridge foundation, Lattice-Shaped Diaphragm Wall (hereinafter for LSDW) is highly concerned in relevant construction area but its research is far from achievement. Based on PFC , the soil arching effect of LSDWs is studied thoroughly in this paper and the special attention is given to its influencing factors. It turns out to be that a differential wall-soil settlement can be found at the lower location of soil core of an LSDW which is one of the trigger factors of soil arching; meanwhile, the differential settlement degree can reflect the exertion degree of soil arching; the shape of soil arching is basically a hemisphere which can be explained by the theory proposed by Hewlett and Randolph; normally, the chamber number is a negative factor for the development of soil arching; the soil arching effect is significantly influenced by the distance of two adjacent wall elements and the foundation depth, and a relatively large or small value of these factors is disadvantageous to the exertion of soil arching; in addition, the soil arching effect increase with the growth of stiffness and friction coefficient of particles and the friction coefficient of particles has insignificant influence on the development of soil arching effect compared with particle stiffness.

关键词: LSDW     soil arching     PFC2D     shape of soil arching     influencing factors    

♮-convexity and its applications in operations

Xin CHEN

《工程管理前沿(英文)》 2017年 第4卷 第3期   页码 283-294 doi: 10.15302/J-FEM-2017057

摘要: -convexity, one of the central concepts in discrete convex analysis, receives significant attentions in the operations literature in recent years as it provides a powerful tool to derive structures of optimal policies and allows for efficient computational procedures. In this paper, we present a survey of key properties of -convexity and some closely related results in lattice programming, several of which were developed recently and motivated by operations applications. As a new contribution to the literature, we establish the relationship between a notion called -differential monotonicity and -convexity. We then illustrate the techniques of applying -convexity through a detailed analysis of a perishable inventory model and a joint inventory and transshipment control model with random capacities.

关键词: L&natur     -convexity     lattice programming     perishable inventory models     random capacity    

Application and development of modern long-span space structures in China

Shilin DONG, Yang ZHAO, Dong XING

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 224-239 doi: 10.1007/s11709-012-0166-6

摘要: Modern long-span space structures, developed during the 1970s and 1980s, are light and effective structures based on new technologies and light-weight high-strength materials, such as membranes and steel cables. These structures include air-supported membrane structures, cable-membrane structures, cable truss structures, beam string structures, suspen-domes, cable domes, composite structures of cable dome and single-layer lattice shell, Tensairity structures and so forth. For the premodern space structures widely used since the mid-twentieth century (such as thin shells, space trusses, lattice shells and ordinary cable structures), new space structures have been developed by the combination of different structural forms and materials. The application of prestressing technology and the innovation of structural concepts and configurations are also associated with modern space structures, including composite space trusses, open-web grid structures, polyhedron space frame structures, partial double-layer lattice shells, cable-stayed grid structures, tree-type structures, prestressed segmental steel structures and so forth. This paper provides a review of the structural characteristics and practical applications in China of modern rigid space structures, modern flexible space structures and modern rigid-flexible combined space structures.

关键词: modern long-span space structures     rigid space structures     flexible space structures     rigid-flexible combined space structures     application and development    

Practical optimization of deployable and scissor-like structures using a fast GA method

M. SALAR, M. R. GHASEMI, B. DIZANGIAN

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 557-568 doi: 10.1007/s11709-018-0497-z

摘要: This paper addresses practical sizing optimization of deployable and scissor-like structures from a new point of view. These structures have been recently highly regarded for beauty, lightweight, determine behavior, proper performance against lateral loads and the ability of been compactly packaged. At this time, there is a few studies done considering practical optimization of these structures. Loading considered here includes wind and gravity loads. In foldable scissor-like structures, connections have a complex behavior. For this reason, in this study, the authors used the ABAQUS commercial package as an analyzer in the optimization procedure. This made the obtained optimal solutions highly reliable from the point of view of applicability and construction requirements. Also, to do optimization task, a fast genetic algorithm method, which has been recently introduced by authors, was utilized. Optimization results show that despite less weight for aluminum models than steel models, aluminum deployable structures are not affordable because they need more material than steel structures and cause more environmental damage.

关键词: optimization     scissor-like structures     deployable structures     genetic algorithm     ABAQUS    

Effect of / molecular structures on pyrolysis performance and heat sink of decalin isomers

《化学科学与工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11705-023-2375-z

摘要: Decalin is considered as an important compound of high-energy-density endothermic fuel, which is an ideal on-board coolant for thermal management of advanced aircraft. However, decalin contains two isomers with a tunable composition, and their effects on the pyrolysis performance, such as the heat sink and coking tendency have not been demonstrated. Herein, we investigated the pyrolysis of decalin isomers, i.e., cis-decalin, trans-decalin and their mixtures (denoted as mix-decalin), in order to clarify the effects of the cis-/trans-structures on the pyrolysis performance of decalin fuels. The pyrolysis results confirmed that conversion of the tested fuels (600–725 °C, 4 MPa) decreased in the order cis-decalin > mix-decalin > trans-decalin. Detailed analyses of the pyrolysis products were used to compare the product distributions from cis-decalin, mix-decalin and trans-decalin, and the yields of some typical components (such as cyclohexene, 1-methylcyclohexene, benzene and toluene) showed significant differences, which could be ascribed to deeper cracking of cis-decalin. Additionally, the heat sinks and coking tendencies of the decalins decreased in the order cis-decalin > mix-decalin > trans-decalin. This work demonstrates the relationship between the cis/trans structures and the pyrolysis performance of decalin, which provides a better understanding of the structure-activity relationships of endothermic hydrocarbon fuels.

关键词: endothermic fuel     decalin     pyrolysis     heat sink     molecular structure    

Lateral shear performance of sheathed post-and-beam wooden structures with small panels

《结构与土木工程前沿(英文)》   页码 1117-1131 doi: 10.1007/s11709-023-0939-0

摘要: Sheathed post-and-beam wooden structures are distinct from light-wood structures. They allow for using sheathing panels that are smaller (0.91 m × 1.82 m) than standard-sized panels (1.22 m × 2.44 m or 2.44 m × 2.44 m). Evidence indicates that nail spacing and panel thickness determine the lateral capacity of the wood frame shear walls. To verify the lateral shear performance of wood frame shear walls with smaller panels, we subjected 13 shear walls, measuring 0.91 m in width and 2.925 m in height, to a low-cycle cyclic loading test with three kinds of nail spacing and three panel thicknesses. A nonlinear numerical simulation analysis of the wall was conducted using ABAQUS finite element (FE) software, where a custom nonlinear spring element was used to simulate the sheathing-frame connection. The results indicate that the hysteretic performance of the walls was mainly determined by the hysteretic performance of the sheathing-frame connection. When same nail specifications were adopted, the stiffness and bearing capacity of the walls were inversely related to the nail spacing and directly related to the panel thickness. The shear wall remained in the elastic stage when the drift was 1/250 rad and ductility coefficients were all greater than 2.5, which satisfied the deformation requirements of residential structures. Based on the test and FE analysis results, the shear strength of the post-and-beam wooden structures with sheathed walls was determined.

关键词: post-and-beam wooden structures with sheathed walls     low reversed cyclic loading     bearing capacity     stiffness     numerical simulation    

A numerical framework for underground structures in layered ground under inclined P-SV waves using stiffness

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 10-24 doi: 10.1007/s11709-022-0904-3

摘要: A numerical framework was proposed for the seismic analysis of underground structures in layered ground under inclined P-SV waves. The free-field responses are first obtained using the stiffness matrix method based on plane-wave assumptions. Then, the domain reduction method was employed to reproduce the wavefield in the numerical model of the soil–structure system. The proposed numerical framework was verified by providing comparisons with analytical solutions for cases involving free-field responses of homogeneous ground, layered ground, and pressure-dependent heterogeneous ground, as well as for an example of a soil–structure interaction simulation. Compared with the viscous and viscous-spring boundary methods adopted in previous studies, the proposed framework exhibits the advantage of incorporating oblique incident waves in a nonlinear heterogeneous ground. Numerical results show that SV-waves are more destructive to underground structures than P-waves, and the responses of underground structures are significantly affected by the incident angles.

关键词: underground structures     seismic response     stiffness matrix method     domain reduction method     P-SV waves    

标题 作者 时间 类型 操作

Robust topology optimization of multi-material lattice structures under material and load uncertainties

Yu-Chin CHAN, Kohei SHINTANI, Wei CHEN

期刊论文

Compressive behavior and energy absorption of polymeric lattice structures made by additive manufacturing

Sheng WANG, Jun WANG, Yingjie XU, Weihong ZHANG, Jihong ZHU

期刊论文

Design and applications of morphing aircraft and their structures

期刊论文

Uncertainty of concrete strength in shear and flexural behavior of beams using lattice modeling

期刊论文

Simulation of interfacial Marangoni convection in gas-liquid mass transfer by lattice Boltzmann method

Shuyong CHEN, Xigang YUAN, Bo FU, Kuotsung YU

期刊论文

slip investigation based on finite element modelling verified by experimental results on wind turbine lattice

Saleh YAGHOOBI, Ahmad SHOOSHTARI

期刊论文

URANS simulation of the turbulent flow in tight lattice bundle

Yiqi YU, Yanhua YANG

期刊论文

超轻折叠夹层圆柱壳的制备及力学性能测试

李万欣, 郑青, 范华林, 冀宾

期刊论文

Soil arching effect of Lattice-Shaped Diaphragm Wall as bridge foundation

Jiujiang WU, Lingjuan WANG, Qiangong CHENG

期刊论文

♮-convexity and its applications in operations

Xin CHEN

期刊论文

Application and development of modern long-span space structures in China

Shilin DONG, Yang ZHAO, Dong XING

期刊论文

Practical optimization of deployable and scissor-like structures using a fast GA method

M. SALAR, M. R. GHASEMI, B. DIZANGIAN

期刊论文

Effect of / molecular structures on pyrolysis performance and heat sink of decalin isomers

期刊论文

Lateral shear performance of sheathed post-and-beam wooden structures with small panels

期刊论文

A numerical framework for underground structures in layered ground under inclined P-SV waves using stiffness

期刊论文