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A systematic design of multifunctional lattice structures with energy absorption and phononic bandgap by topology and parameter optimization

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International Journal of Smart and Nano Materials 2023年第3期14卷 265-285页

作者： Hongling Ye Wenjie Shen Weiwei Wang ran tao Faculty of Materials and Manufacturing Beijing University of TechnologyBeijingPRChina College of Engineering Peking UniversityBeijing 100871PR China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijingPRChina

Lattice structure can realize excellent multifunctional charac-teristics because of its huge design space,and the cellular configuration directly affects the lattice structural performance and lightweight.A novel energy-absorbing multifunctional lat-tice structure with phononic bandgap is presented by topol-ogy and parameter optimization in this ***,the two-dimensional(2D)cellular configuration is lightweight designed by using independent continuous mapping(ICM)topology optimization *** 2D cell is reconstructed by geo-metric parameters and rotated into a three-dimensional(3D)cell by using chiral shape to achieve ***,the surrogated model with energy absorption as the object and first-order natural frequency as the constraint is estab-lished to optimize a parametric 3D cell based on the Response Surface Methodology(RSM).Finally,the lattice struc-tures are assembled with dodecagonal staggered arrange-ments to avoid the deformation interference among the adjacent *** addition,the lattice structural energy absorp-tion and bandgap characteristics are analyzed and *** to Kelvin lattice structure,the optimal lattice struc-ture shows significant improvement in energy absorption ***,the proposed design also performs well in damping characteristics of the high-frequency and *** lattice structural optimization design framework has great meaning to achieve the equipment structural light-weight and multi-function in the aerospace field.

关键词： Multifunctional lattice structure energy absorption phononic bandgap topology optimization parameter optimization

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Shape and Size Optimization of Truss Structures under Frequency Constraints Based on Hybrid Sine Cosine Firefly Algorithm

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Computer Modeling in Engineering & Sciences 2023年第1期134卷 405-428页

作者： ran tao Xiaomeng Yang Huanlin Zhou Zeng Meng School of Civil Engineering Hefei University of TechnologyHefei230009China

Shape and size optimization with frequency constraints is a highly nonlinear problem withmixed design variables,non-convex search space,and multiple local ***,a hybrid sine cosine firefly algorithm(HSCFA)is proposed to acquire more accurate solutions with less finite element *** full attraction model of firefly algorithm(FA)is analyzed,and the factors that affect its computational efficiency and accuracy are revealed.A modified FA with simplified attraction model and adaptive parameter of sine cosine algorithm(SCA)is proposed to reduce the computational complexity and enhance the convergence ***,the population is classified,and different populations are updated by modified FA and SCA ***,the random search strategy based on Lévy flight is adopted to update the stagnant or infeasible solutions to enhance the population *** selection technique is applied to save the promising solutions and further improve the convergence ***,the adaptive penalty function is employed to deal with the ***,the performance of HSCFA is demonstrated through the numerical examples with nonstructural masses and frequency *** results show that HSCFA is an efficient and competitive tool for shape and size optimization problems with frequency constraints.

关键词： Firefly algorithm sine cosine algorithm frequency constraints structural optimization

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The FrFT convolutional face: toward robust face recognition using the fractional Fourier transform and convolutional neural networks

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Science China(Information Sciences) 2020年第1期63卷 235-237页

作者： Xin WU ran tao Danfeng HONG Yue WANG The School of Information and Electronics Beijing Institute of Technology Beijing Key Laboratory of Fractional Signals and Systems Beijing Institute of Technology Remote Sensing Technology Institute (IMF) German Aerospace Center (DLR) Signal Processing in Earth Observation (SiPEO) Technical University of Munich (TUM)

Dear editor,Recently, advances in techniques, such as deep learning, have attracted increasing interest in the field of biometrics [1–3]. In facial recognition systems, facial images are observed to inevitably suffer... 详细信息

关键词： image AB The FrFT convolutional face toward robust face recognition using the fractional Fourier transform and convolutional neural networks Fourier

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Intelligent feedback analysis on a deep excavation for the gravity anchorage foundation of a super suspension bridge

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岩石力学与工程学报 2019年第A01期38卷 2898-2912页

作者： ran tao LIU Daan MEI Songhua WANG Weiwei TAN Lihua Institute of Geology and Geophysics Chinese Academy of Sciences University of Chinese Academy of Sciences Zhongnan Engineering Co. Ltd. CCCC First Highway Engineering Co. Ltd.

In order to ensure the construction safety of the 38.5 m deep excavation for the gravity anchorage foundation of Fuma Yangtze River Bridge, an intelligent feedback analysis was applied to this excavation project. First, a three-dimensional numerical model that simulating the construction process of the excavation was built,and the deformations of the supporting structures were calculated by the finite difference program FLAC3 D. Then,the non-linear mapping relationship between the geomechanical parameters and the excavation-induced displacements was established by the back-propagation neural network(BPNN). Last,the geomechanical parameters were optimized intelligently by the genetic algorithm(GA) based on the developed BPNN model and the measured displacements,and the deformations during the subsequent excavation stages were predicted based on the back-calculated parameters. The research results showed that:the back-calculated values of E1,μ1,c1,and φ1 of the completely weathered stratum,and E2 of the heavily weathered stratum were greater than the initial values,while the inversion value of E3 of the moderately weathered stratum was smaller than the initial value. The magnitudes and the variation tendencies of the predicted displacements were in good accordance with the measured displacements. At the end of the excavation,the retaining piles and the top beams had a maximum displacement of 15–20 mm,exhibiting a quite small magnitude as comparing with other case histories. Local concentration of shear stress mainly occurred at the soil-pile interface and at the toe of the excavation slope,and the plastic zones mainly appeared in the completely weathered stratum. After the completion of the excavation,there were no yielding elements in the model,and the convergence of the numerical computation was achieved,indicating the excavation was in a stable state. This study lays the basis for the subsequent construction and operation of the bridge,and offers a significant refe

关键词： foundations suspension bridge anchorage deep excavation parameter inversion deformation prediction intelligent feedback analysis

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Comparative study of reduced-order modeling method for the cavitating flow over a hydrofoil

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Journal of Hydrodynamics 2023年第4期35卷 679-699页

作者： Yan-zhao Wu ran tao Di Zhu Ruo-fu Xiao College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System China Agricultural UniversityBeijing100083China College of Engineering China Agricultural UniversityBeijing100083China

As a high-dimensional complex nonlinear dynamic system,the analysis of the essence of flow has always been a difficult problem,especially in the flow including phase *** recent years,it has become a feasible method to reduce the dimension of flow structure by reduced-order modeling(ROM)*** this paper,through the cavitation numerical simulation of NACA0015 hydrofoil,two ROM methods are used to reduce and restore three different cavitation respectively-proper orthogonal decomposition(POD)and dynamic mode decomposition(DMD).The applicability of two methods in cavitation is discussed and reasons are *** results show that for stable cavitation,POD,DMD methods can accurately restore the flow field of a few modes with high *** unstable cavitation,only POD method can restore real flow field *** situation is mainly due to the fact that POD,DMD method are applicable to different energy ratios,and different main mode selection criterion of DMD will lead to different main *** can greatly simplify the complexity of *** a reasonable ROM can improve the accuracy of a small amount of database,and provide a basis for intelligent prediction of flow analysis.

关键词： Hydrofoil cavitation reduced-order model proper orthogonal decomposition dynamic mode decomposition

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Compressive Mechanical and Heat Conduction Properties of AlSi10Mg Gradient Metamaterials Fabricated via Laser Powder Bed Fusion

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CHINESE JOURNAL OF MECHANICAL ENGINEERING 2024年第1期37卷 1-18页

作者： Sun, Qidong Zhi, Geng Zhou, Sheng tao, ran Qi, Junfeng Beijing Inst Technol Inst Adv Struct Technol Beijing 100081 Peoples R China Beijing Inst Technol Beijing Key Lab Lightweight Multifunct Composite M Beijing 100081 Peoples R China China Aerosp Sci & Technol Corp Inst 2 Beijing Inst Radio Measurement Beijing 100854 Peoples R China Beijing Spacecrafts Mfg Factory Beijing 100094 Peoples R China

Metamaterials are defined as artificially designed micro-architectures with unusual physical properties, including optical, electromagnetic, mechanical, and thermal characteristics. This study investigates the compressive mechanical and heat transfer properties of AlSi10Mg gradient metamaterials fabricated by Laser Powder Bed Fusion (LPBF). The morphology of the AlSi10Mg metamaterials was examined using an ultrahigh-resolution microscope. Quasi-static uniaxial compression tests were conducted at room temperature, with deformation behavior captured through camera recordings. The findings indicate that the proposed gradient metamaterial exhibits superior compressive strength properties and energy absorption capacity. The Gradient-SplitP structure demonstrated better compressive performance compared to other strut-based structures, including Gradient-Gyroid and Gradient-Lidinoid structures. With an apparent density of 0.796, the Gradient-SplitP structure exhibited an outstanding energy absorption capacity, reaching an impressive 23.57 MJ/m3. In addition, heat conductivity tests were performed to assess the thermal resistance of these structures with different cell configurations. The gradient metamaterials exhibited higher thermal resistance and lower thermal conductivity. Consequently, the designed gradient metamaterials can be considered valuable in various applications, such as thermal management, load-bearing, and energy absorption components.

关键词： Compressive mechanical properties Thermal conductivity Finite element analysis Gradient metamaterials Laser powder bed fusion

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A New Tensor Factorization Based on the Discrete Simplified Fractional Fourier Transform

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Journal of Beijing Institute of Technology 2021年第3期30卷 274-279页

作者： Xinhua Su ran tao the School of Sports Engineering Beijing Sport University the School of Information and Electronics Beijing Institute of Technology

Tensor analysis approaches are of great importance in various fields such as computation vision and signal processing. Thereinto, the definitions of tensor-tensor product(t-product)and tensor singular value decomposition(t-SVD) are significant in practice. This work presents new t-product and t-SVD definitions based on the discrete simplified fractional Fourier transform(DSFRFT). The proposed definitions can effectively deal with special complex tenors, which further motivates the transform based tensor analysis approaches. Then, we define a new tensor nuclear norm induced by the DSFRFT based t-SVD. In addition, we analyze the computational complexity of the proposed t-SVD, which indicates that the proposed t-SVD can improve the computational efficiency.

关键词： tensor-tensor product tensor singular value decomposition fractional Fourier transform

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Research Progress of the Sampling Theorem Associated with the Fractional Fourier Transform

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Journal of Beijing Institute of Technology 2021年第3期30卷 195-204+320页

作者： Jinming Ma ran tao Beijing Key Laboratory of Fractional Signals and Systems School of Information and Electronics Beijing Institute of Technology

Sampling is a bridge between continuous-time and discrete-time signals, which is important to digital signal processing. The fractional Fourier transform(FrFT) that serves as a generalization of the FT can characterize signals in multiple fractional Fourier domains, and therefore can provide new perspectives for signal sampling and reconstruction. In this paper, we review recent developments of the sampling theorem associated with the FrFT, including signal reconstruction and fractional spectral analysis of uniform sampling, nonuniform samplings due to various factors, and sub-Nyquist sampling, where bandlimited signals in the fractional Fourier domain are mainly taken into consideration. Moreover, we provide several future research topics of the sampling theorem associated with the FrFT.

关键词： fractional Fourier transform nonuniform sampling signal reconstruction spectral analysis uniform sampling

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Analysis of the interactive meaning of journalistic images of the human papillomavirus vaccine and the perceptions of female undergraduate students

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International Journal of Nursing Sciences 2020年第S01期7卷 61-66页

作者： Jingxi Chen ran tao Qiaomin Guo School of Languages and Communication studies Beijing Jiaotong UniversityBeijingChina School of Journalism and Communication Peking UniversityBeijingChina School of New Media Peking UniversityBeijingChina

Objectives:This paper focuses on the underlying mechanisms of women's perceptions of persuasive visual health ***:In the image viewing process,a separation between the image producer and the image viewer occurs,and the connection between the two is *** mixed method research included modal discourse analysis(coding based on visual grammar theory),an eye tracking experiment,a questionnaire survey,and in-depth semi-structured *** interactive meanings of journalistic images related to the human papillomavirus(HPV)vaccine were identified through four sets of *** addition,the perceptions of female viewers were ***:In the first set of stimuli,i.e.,the infographic,the female participants focused most of their attention on information about the nine-valent HPV *** analysis of the interactive meaning of two sets of journalistic pictures,i.e.,fictional pictures and nonfictional pictures,indicated that the image producers did not implement useful viewer involvement strategies to persuade ***,female viewers focused their attention on the"similar other"during the viewing process,gazing at the patient the longest as the primary area of interest(AOI).Conclusions:The study indicates that the current persuasive visual information about the HPV vaccine needs further improvement due to the high demand for information about HPV from the Chinese female audience.

关键词： Attention Eye tracking Journalistic image Medical decision making Papillomavirus vaccines Visual grammar

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Effect of leading edge roughness on cavitation inception and development on thin hydrofoil

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排灌机械工程学报 2017年第11期35卷 921-926,940页

作者： tao ran XIAO Ruofu FARHAT Mohamed Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Net- work System China Agricultural University Beijing 100083 China Laboratory for Hydraulic Ma- chines Ecole Polyteehnique Federale de Lausanne Lausanne 1007 Switzerland

The cavitation incipience and development of water flow over a thin hydrofoil placed in the test section of high-speed cavitation tunnel were *** with smooth and rough leading edge were tested for different upstream velocities and incidence *** observations clearly revealed that cavitation incipience is enhanced by roughness at incidence angle below 2°.This is in line with the former reports,according to whose roughness element decreases the wettability and traps a larger amount of *** a result,surface nucleation is enhanced with an increased risk of ***,for higher incidence angles(>3°),it was found that cavitation incipience is significantly delayed by roughness while developed cavitation is almost the same for both smooth and rough *** unexpected incipience delay is related to the change in the boundary layer structure due to *** was also reported a significant influence of roughness on the dynamic of developed cavitation and shedding of transient cavities.

关键词： cavitation inception surface roughness sheet cavitation cloud cavitation hydrofoil

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