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Improving the efficiency of large scale topology optimization through on‐the‐fly reduced order model construction 下载免费PDF全文
Christian Gogu 《International journal for numerical methods in engineering》2015,101(4):281-304
Topology optimization of large scale structures is computationally expensive, notably because of the cost of solving the equilibrium equations at each iteration. Reduced order models by projection, also known as reduced basis models, have been proposed in the past for alleviating this cost. We propose here a new method for coupling reduced basis models with topology optimization to improve the efficiency of topology optimization of large scale structures. The novel approach is based on constructing the reduced basis on the fly, using previously calculated solutions of the equilibrium equations. The reduced basis is thus adaptively constructed and enriched, based on the convergence behavior of the topology optimization. A direct approach and an approach with adjusted sensitivities are described, and their algorithms provided. The approaches are tested and compared on various 2D and 3D minimum compliance topology optimization benchmark problems. Computational cost savings by up to a factor of 12 are demonstrated using the proposed methods. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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A consistent grayscale‐free topology optimization method using the level‐set method and zero‐level boundary tracking mesh 下载免费PDF全文
Shintaro Yamasaki Atsushi Kawamoto Tsuyoshi Nomura Kikuo Fujita 《International journal for numerical methods in engineering》2015,101(10):744-773
This paper proposes a level‐set based topology optimization method incorporating a boundary tracking mesh generating method and nonlinear programming. Because the boundary tracking mesh is always conformed to the structural boundary, good approximation to the boundary is maintained during optimization; therefore, structural design problems are solved completely without grayscale material. Previously, we introduced the boundary tracking mesh generating method into level‐set based topology optimization and updated the design variables by solving the level‐set equation. In order to adapt our previous method to general structural optimization frameworks, the incorporation of the method with nonlinear programming is investigated in this paper. To successfully incorporate nonlinear programming, the optimization problem is regularized using a double‐well potential. Furthermore, the sensitivities with respect to the design variables are strictly derived to maintain consistency in mathematical programming. We expect the investigation to open up a new class of grayscale‐free topology optimization. The usefulness of the proposed method is demonstrated using several numerical examples targeting two‐dimensional compliant mechanism and metallic waveguide design problems. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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提出了从改善结构设计,采用新材料的角度出发解决困扰我国数控机床加工精度的难题。在对纤维增强树脂混凝土作为机床基础件的国内外研究现状分析的基础上,提出基于拓扑优化的方法、结合数控机床工作的环境条件,并考虑材料自身力学本构关系来对纤维增强树脂混凝土机床基础件进行优化设计。最后给出了具体解决策略和思路。 相似文献
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Distributed topology management for wireless multimedia sensor networks: exploiting connectivity and cooperation 下载免费PDF全文
Sudip Misra Goutam Mali Ayan Mondal 《International Journal of Communication Systems》2015,28(7):1367-1386
In this paper, we propose a distributed topology management algorithm, named T‐Must, which orchestrates coalition formation game between camera and scalar sensor (SS) nodes, for use in wireless multimedia sensor networks. In the proposed solution, connectivity among the peer camera sensor (CS) nodes is maintained, and coverage is ensured between them. Only the scalar data are not sufficient to describe an event in a particular monitored area. In many cases, multimedia data (specifically, video data) are required to provide more precise information about the event. As the CS nodes, which sense and transmit multimedia data, are costlier than the SS nodes, the former are deployed in the monitored area in lesser numbers compared to the latter ones. In case of CS nodes, power consumption due to sensing is also significant, similar to power consumption for the transmission and reception of packets. Therefore, in this work, in order to increase the network lifetime, topology is controlled by forming coalition between the CS and SS nodes. Upon occurrence of an event, the SS nodes send scalar data to their associated CS nodes. If the scalar data received from SS nodes cross a preconfigured threshold, the associated CS node in the coalition starts sensing the event, captures the video data, and forwards the video data toward other coalitions or sink. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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采用变密度法和折衷规划法建立了结构的多目标拓扑优化模型,并利用分析层级法确定了子目标权重。以"U"型结构为对象进行了多目标拓扑优化设计,得到了结构质量较轻的新结构形式。该方法可应用于结构的优化设计。 相似文献