检索结果-内蒙古大学图书馆

Variable stiffness design optimization of fiber-reinforced composite laminates with regular and irregular holes considering fiber continuity for additive manufacturing

引用

Chinese Journal of Aeronautics 2025年第3期38卷 334-354页

作者： Yi LIU Zunyi DUAN Chunping ZHOU Yuan SI Chenxi GUAN Yi XIONG Bin XU Jun YAN Jihong ZHU School of Mechanics Civil Engineering&ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China Key Lab for Airborne Hi-performance Electro-magnetic Window RISACJinan 130012China School of System Design and Intelligent Manufacturing Southern University of Science and TechnologyShenzhen 518055China State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of TechnologyDalian 116024China State IJR Center of Aerospace Design and Additive Manufacturing MIIT Lab of Metal Additive Manufacturing and Innovative DesignNorthwestern Polytechnical UniversityXi’an 710072China

Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel, and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization (NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples cons

关键词： Variable stiffness composite laminates Discrete material interpolation scheme Normal distribution fiber optimization Discrete fiber continuous filtering strategy Additive manufacturing of composite laminates

来源：评论

学校读者我要写书评

暂无评论

Variable stiffness design optimization of fiber-reinforced composite laminates with regular and irregular holes considering fiber continuity for additive manufacturing

引用

Chinese Journal of Aeronautics 2025年第3期 338-358页

作者： Yi LIU Zunyi DUAN Chunping ZHOU Yuan SI Chenxi GUAN Yi XIONG Bin XU Jun YAN Jihong ZHU School of Mechanics Civil Engineering & ArchitectureNorthwestern Polytechnical University Research & Development Institute of Northwestern Polytechnical University in Shenzhen Key Lab for Airborne Hi-performance Electro-magnetic Window RISAC School of System Design and Intelligent Manufacturing Southern University of Science and Technology State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsInternational Research Center for Computational MechanicsDalian University of Technology State IJR Center of Aerospace Design and Additive Manufacturing MIIT Lab of Metal Additive Manufacturing and Innovative DesignNorthwestern Polytechnical University

Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel,and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization(NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples consid

关键词：

来源：评论

学校读者我要写书评

暂无评论

Actions against the double burden of malnutrition in Peru: a community-informed system dynamics model

引用

The Lancet Regional Health - Americas 2025年 46卷 101102-101102页

作者： Seferidi, Paraskevi Guzman-Abello, Laura Ballard, Ellis Creed-Kanashiro, Hilary M. Huicho, Luis Miranda, J Jaime Millett, Christopher Bernabe-Ortiz, Antonio Public Health Policy Evaluation Unit School of Public Health Imperial College London London United Kingdom Department of Design School of Architecture and Design Universidad de los Andes Bogota Colombia Social System Design Lab Brown School at Washington University in St. Louis St. Louis United States Instituto de Investigación Nutricional Lima Peru Centro de Investigación en Salud Materna e Infantil Centro de Investigación para el Desarrollo Integral y Sostenible and Facultad de Medicina Universidad Peruana Cayetano Heredia Lima Peru CRONICAS Centre of Excellence in Chronic Diseases Universidad Peruana Cayetano Heredia Lima Peru Sydney School of Public Health Faculty of Medicine and Health University of Sydney Sydney Australia NOVA National School of Public Health Public Health Research Centre Comprehensive Health Research Center NOVA University Lisbon Lisbon Portugal

Background: Peru's progress in reducing stunting has stagnated since 2018, while the country is facing increasing levels of overnutrition, leading to a double burden of malnutrition. However, this shift in nutrition burden is not reflected in Peru's nutrition policy agenda. This study aims to identify leverage points for actions against population-level double burden of malnutrition in Peru. Methods: We developed a system dynamics model that simulates changes in overweight and stunting over time in Peru through changes in food system drivers. The model was conceptually informed by policymakers, practitioners and community members in Peru and used quantitative and qualitative data from secondary sources and published literature. Findings: The model indicated that several overnutrition policies, including policies targeting food availability and affordability, may decelerate but not halt the increase of overweight in the country, mainly due to industry resistance. However, in the long term, the reallocation of resources towards overnutrition policies may inadvertently hinder progress towards stunting targets. Transforming nutrition policy governance, from siloed overnutrition and undernutrition policies towards a common policy framework against the double burden of malnutrition was the only modelled scenario that halted the rise in overnutrition, while keeping Peru on course to reach its stunting goals. Interpretation: Transition away from policy landscapes that focus on single nutrition outcomes towards synergistic actions that target malnutrition in all forms is a long-term solution towards achieving global nutrition goals. Such policy transitions are especially important in low and middle-income countries like Peru, which are affected by the double burden of malnutrition. Funding: This study was supported by a research grant from the Biotechnology and Biological Sciences Research Council (BBSRC) (grant reference: BB/T009004/1). © 2025 The Authors

关键词： Double burden of malnutrition Double-duty actions Peru system dynamics

来源：评论

学校读者我要写书评

暂无评论

A special case of DOAV estimation in white Gaussian noise

A special case of DOAV estimation in white Gaussian noise

引用

2008 IEEE Military Communications Conference, MILCOM 2008 - Assuring Mission Success

作者： Montlouis, W. WEMSS Lab. Cambridge MA 02140 United States System Architecture Design and Integration Directorate Raytheon Company Sudbury MA United States Northeastern University Boston MA 02115 United States

ISBN: (纸本)9781424426775

Estimating the location of a point source at the output of an array system can be challenging, especially when one needs to make the tradeoff between accuracy and computational complexity. Using a rectangular array, the most widely studied parameter estimation problem is the azimuth and elevation only case. Even in this two parameter case, it usually requires a two-dimensional search in order to obtain the desired information. The problem formulated in this paper is a four parameter estimation problem of significant importance. To accomplish this, the movement of the point source is modeled in a small window of observation to generate the azimuth, elevation and angular velocities. Often it is easier to develop an algorithm for the Uniformly Distributed Linear Array (ULA) case due to the well-behaved properties of this linear array structure. This paper presents a new search free approach to simultaneously estimate azimuth, elevation angles and respective angular Velocities (DOAV) of moving sources using a rectangular array of antennas. ©2008 IEEE.

关键词： Gaussian noise (electronic)

来源：评论

学校读者我要写书评

暂无评论

Memory fast-forward: A low cost special function unit to enhance energy efficiency in GPU for big data processing 15

Memory fast-forward: A low cost special function unit to enh...

引用

design, Automation and Test in Europe Conference and Exhibition

作者： Eunhyeok Park Junwhan Ahn Sungpack Hong Sungjoo Yoo Sunggu Lee Embedded System Architecture Lab POSTECH Design Automation Lab Seoul National University Oracle Labs

ISBN: (纸本)9783981537048

Big data processing, e.g., graph computation and MapReduce, is characterized by massive parallelism in computation and a large amount of fine-grained random memory accesses often with structural localities due to graph-like data dependency. Recently, GPU is gaining more and more attention for servers due to its capability of parallel computation. However, the current GPU architecture is not well suited to big data workloads due to the limited capability of handling a large number of memory requests. In this paper, we present a special function unit, called memory fast-forward (MFF) unit, to address this problem. Our proposed MFF unit provides two key functions. First, it supports pointer chasing which enables computation threads to issue as many memory requests as possible to increase the potential of coalescing memory requests. Second, it coalesces memory requests bound for the same cache block, often due to structural locality, thereby reducing memory traffics. Both pointer chasing and memory request coalescing contribute to reducing memory stall time as well as improving the real utilization of memory bandwidth, by removing duplicate memory traffics, thereby improving performance and energy efficiency. Our experiments with graph computation algorithms and real graphs show that the proposed MFF unit can improve the energy efficiency of GPU in graph computation by average 54.6% at a negligible area cost.

关键词： Graphics processing units Instruction sets Registers Memory management Arrays Big data

来源：评论

学校读者我要写书评

暂无评论

Doppler diversity for OFDM wireless mobile communications. Part I: Frequency domain approach

Doppler diversity for OFDM wireless mobile communications. P...

引用

57th IEEE Semiannual Vehicular Technology Conference (VTC2003)

作者： Kim, Byung-Chul Lu, I-Tai System Architecture Design Lab TN Business Samsung Electronics Co. Ltd. P.O. Box 105 Suwon Gyeonggi-do 442-742 Korea Republic of Department of Electrical Engineering Polytechnic University 105 Maxess Road Melville NY 11747 United States

A novel frequency domain Doppler diversity technique for OFDM systems is proposed. The received OFDM signal is first frequency shifted to generate various diversity branches. After demodulation, branch outputs are individually weighted and added together. For Doppler spread signal, it alters fading statistics and improves the bit error rate. Extensive simulations show that combining three diversity branches with proper frequency shifts reduces BER by an order when the normalized Doppler spread is larger than 0.3.

关键词： Mobile telecommunication systems

来源：评论

学校读者我要写书评

暂无评论

Space-time-frequency processing for OFDM wireless mobile communications

Space-time-frequency processing for OFDM wireless mobile com...

引用

57th IEEE Semiannual Vehicular Technology Conference (VTC2003)

作者： Kim, Byung-Chul Lu, I-Tai System Architecture Design Lab. TN Business Samsung Electronics Co. Ltd. P.O.Box 105 Suwon Gyeonggi-do 442-742 Korea Republic of Department of Electrical Engineering Polytechnic University 105 Maxess Road Melville NY 11747 United States

The space-time-frequency processing for OFDM wireless mobile communications was presented. The novel space-time-frequency processing schemes for OFDM mobile communication systems were implemented by using antenna arrays. It was stated that, when the angular spread is small, multiple antennas might not be able to provide space diversity.

关键词： Mobile telecommunication systems

来源：评论

学校读者我要写书评

暂无评论

Doppler diversity for OFDM wireless mobile communications. Part II: Time-frequency processing

Doppler diversity for OFDM wireless mobile communications. P...

引用

57th IEEE Semiannual Vehicular Technology Conference (VTC2003)

作者： Kim, Byung-Chul Lu, I-Tai System Architecture Design Lab. TN Business Samsung Electronics Co. Ltd. P.O. Box 105 Suwon Gyeonggi-do 442-742 Korea Republic of Department of Electrical Engineering Polytechnic University 105 Maxess Road Melville NY 11747 United States

A study was performed on Doppler diversity for orthogonal frequency-division multiplexing (OFDM) wireless mobile communications. A novel time-frequency processing scheme was developed to exploit Doppler diversity. The extensive simulations showed that the proposed time-frequency MMSE processing scheme altered the statistics of the fading to improve BER significantly.

关键词： Mobile telecommunication systems

来源：评论

学校读者我要写书评

暂无评论

Inline Photometrically Calibrated Hybrid Visual SLAM

Inline Photometrically Calibrated Hybrid Visual SLAM

引用

IEEE/RSJ International Conference on Intelligent Robots and systems (IROS)

作者： Nicolas Abboud Malak Sayour Imad H. Elhajj John Zelek Daniel Asmar Vision and Robotics Lab Maroun Semaan Faculty of Engineering and Architecture American University of Beirut Beirut Lebanon Department of System Design Engineering University of Waterloo Waterloo Canada

ISBN: (数字)9798350377705

ISBN: (纸本)9798350377712

This paper presents an integrated approach to Visual SLAM, merging online sequential photometric calibration within a Hybrid direct-indirect visual SLAM (H-SLAM). Photometric calibration helps normalize pixel intensity values under different lighting conditions, and thereby improves the direct component of our H-SLAM. A tangential benefit also results to the indirect component of H-SLAM given that the detected features are more stable across variable lighting conditions. Our proposed photometrically calibrated H-SLAM is tested on several datasets, including the TUM monoVO as well as on a dataset we created. Calibrated H-SLAM outperforms other state of the art direct, indirect, and hybrid Visual SLAM systems in all the experiments. Furthermore, in online SLAM tested at our site, it also significantly outperformed the other SLAM systems.

关键词： Visualization Simultaneous localization and mapping Measurement units Merging Lighting Inertial navigation Feature extraction Calibration Intelligent robots

来源：评论

学校读者我要写书评

暂无评论

Doppler diversity for OFDM wireless mobile communications. Part II: time-frequency processing

Doppler diversity for OFDM wireless mobile communications. P...

引用

IEEE Conference on Vehicular Technology (VTC)

作者： Byung-Chul Kim I-Tai Lu System Architecture Design Lab TN Business Samsung Electronics Company Limited Suwon Gyeonggi South Korea Department of Electrical and Computer Engineering Polytechnic University Melville NY USA

A novel time-frequency processing scheme is developed to exploit Doppler diversity of time varying multipath channel for OFDM mobile communication systems. Extensive simulations show that the proposed time-frequency M... 详细信息

ISBN: (纸本)0780377575

关键词： OFDM Wireless communication Mobile communication Time frequency analysis Fading Frequency diversity Finite impulse response filter Statistics Bit error rate Signal generators

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：