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Damping characteristics of friction damped braced frame and its effectiveness in the mega-sub controlled structure system 被引量:19
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作者 连业达 张洵安 Sheldon Cherry 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2007年第2期171-181,共11页
Based on energy dissipation and structural control principle, a new structural configuration, called the megasub controlled structure (MSCS) with friction damped braces (FDBs), is first presented. Meanwhile, to ca... Based on energy dissipation and structural control principle, a new structural configuration, called the megasub controlled structure (MSCS) with friction damped braces (FDBs), is first presented. Meanwhile, to calculate the damping coefficient in the slipping state a new analytical method is proposed. The damping characteristics of one-storey friction damped braced frame (FDBF) are investigated, and the influence of the structural parameters on the energy dissipation and the practical engineering design are discussed. The nonlinear dynamic equations and the analytical model of the MSCS with FDBs are established. Three building structures with different structural configurations, which were designed with reference to the conventional mega-sub structures such as used in Tokyo City Hall, are comparatively investigated. The results illustrate that the structure presented in the paper has excellent dynamic properties and satisfactory control effectiveness. 展开更多
关键词 friction damped braces mega-sub controlled structure energy dissipation vibration control nonlinear dynamic system
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SOME RESULTS ON CONTROLLED FRAMES IN HILBERT SPACES 被引量:2
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作者 Kamran MUSAZADEH Hassan KHANDANI 《Acta Mathematica Scientia》 SCIE CSCD 2016年第3期655-665,共11页
We use two appropriate bounded invertible operators to define a controlled frame with optimal frame bounds. We characterize those operators that produces Parseval controlled frames also we state a way to construct nea... We use two appropriate bounded invertible operators to define a controlled frame with optimal frame bounds. We characterize those operators that produces Parseval controlled frames also we state a way to construct nearly Parseval controlled frames. We intro- duce a new perturbation of controlled frames to obtain new frames from a given one. Also we reduce the distance of frames by appropriate operators and produce nearly dual frames from two given frames which are not dual frames for each other. 展开更多
关键词 frameS Parseval frames dual frames controlled frames reconstruction formula PERTURBATION
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Study on semi-active control of mega-sub controlled structure by MR damper subject to random wind loads 被引量:7
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作者 Qin Xiangjun Zhang Xun'an Sheldon Cherry 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2008年第3期285-294,共10页
The recently proposed mega-sub controlled structure (MSCS), a new type of structure associated with the design and construction of super-tall buildings, has attracted the attention of designers for use in enhancing ... The recently proposed mega-sub controlled structure (MSCS), a new type of structure associated with the design and construction of super-tall buildings, has attracted the attention of designers for use in enhancing the control effectiveness in mega-frame buildings. In this paper, a dynamic equation and method to assemble parameter matrixes for a mega-sub controlled structure under random wind loads is presented. Semi-active control using magnetorheological dampers for the MSCS under random wind loads is investigated, and is compared with a corresponding system without dampers. A parametric study of the relative stiffness ratio and relative mass ratio between the mega-frame and the substructures, as well as the additional column stiffness ratio that influences the response control effectiveness of the MSCS, is discussed. The studies reveal, for the first time, that different control mechanisms exist. The results indicate that the proposed structure employing semi-active control can offer an effective control mechanism. Guidelines for selecting parameters are provided based on the analytical study. 展开更多
关键词 mega-sub controlled structure (MSCS) semi-active control magnetorheological damper relative stiffness ratio relative mass ratio additional column stiffness ratio wind load
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Stationary-frame current control strategy for transverse flux permanent-magnet machine
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作者 王建宽 崔巍 江建中 《Journal of Shanghai University(English Edition)》 CAS 2008年第2期158-162,共5页
A new stationary-frame AC current control strategy that can eliminate steady-state errors is discussed and applied to the control of transverse flux permanent-magnet machine (TFPM). Based on the principle of modulat... A new stationary-frame AC current control strategy that can eliminate steady-state errors is discussed and applied to the control of transverse flux permanent-magnet machine (TFPM). Based on the principle of modulation and demodulation, this AC controller can achieve the same frequency response characteristic as the equivalent DC controller. Validity of the TFPM control system using this current control strategy is confirmed with simulation results. 展开更多
关键词 transverse flux permanent-magnet machine (TFPM) current controller stationary frame modulation.
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Full-scale dynamic testing of response-controlled buildings and their components:concepts,methods,and findings 被引量:2
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作者 Kazuhiko Kasai Kazuhiro Matsuda 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第S1期167-181,共15页
A series of shake-table tests was conducted by inserting and replacing 4 different types of dampers,or by removing them in a full-scale 5-story steel frame building. The objective is to validate response-control techn... A series of shake-table tests was conducted by inserting and replacing 4 different types of dampers,or by removing them in a full-scale 5-story steel frame building. The objective is to validate response-control technologies that are increasingly adopted for major Japanese buildings without being attested to-date by a major earthquake. Test results are briefly described,and good performance of the dampers and frame demonstrated. The concepts of the full-scale building tests and various contributions are discussed. The difficulty associated with full-scale dynamic testing is explained. 展开更多
关键词 response-controlled building steel frame steel damper viscous damper oil damper viscoelastic damper
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Research on Intelligent Control of Roving Frame
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作者 王有庆 李从心 王占杭 《Journal of Donghua University(English Edition)》 EI CAS 2003年第4期141-144,共4页
A new model of roving frame FA467, which uses four frequency inverters to replace the complex mechanical transmission, is discussed. A Neuron-PID is designed to reduce the effect of various parametric variations such ... A new model of roving frame FA467, which uses four frequency inverters to replace the complex mechanical transmission, is discussed. A Neuron-PID is designed to reduce the effect of various parametric variations such as load inertia. To ensure the constant spinning tension all over the spinning process, a feedforward controller using iterative learning control algorithm is desigend to avoid disturbances caused by changes of temperature, humidity and so on. The simulation result is shown to illustrate the effectiveness of the proposed algorithm, and now the roving frame FA467 has been developed successfully. 展开更多
关键词 roving frame Neuron-PID controller iterative learning control frequency inverter
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The damage control in tibial pilon open fractures with a new external fixator delta frame
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作者 Giuseppe Rollo Andrea Pasquino +5 位作者 Paolo Pichierri Michele Bisaccia Alessandro Stasi MarcoGiaracuni Niki Cazzella Luigi Meccariello 《Journal of Acute Disease》 2017年第5期222-226,共5页
Objective: To evaluate the effectiveness of the damage control, in emergency to treat the open tibial pilon fractures with Dolphix? External Fixator Frame(CITIEFFE?, Calderara di Reno, Bologna, Italy). Methods: From J... Objective: To evaluate the effectiveness of the damage control, in emergency to treat the open tibial pilon fractures with Dolphix? External Fixator Frame(CITIEFFE?, Calderara di Reno, Bologna, Italy). Methods: From January 2017 to August 2017, at the Department of Orthopedics and Traumatology of Vito Fazzi Hospital Lecce, we treated 23 open tibial pilon fractures with Dolphix? External Fixator Frame(CITIEFFE?, Calderara di Reno, Bologna, Italy). The evaluation criteria of the case series were: the time needed to assemble the external fixator;the time taked to treat the ankle associated lesions;the time of skin healing;the ankle alignment;the subjective/objective Ovadia and Beals score;and complications. The Endpoint assessment was set at the days of the definitive surgery. Results: The results in terms of alignment, biomechanical stability of the frame, healing of soft tissue, complications were as good as the objective and subjective results according Ovadia and Beals score. Conclusion:Pilon fractures are complex and often present complications;the damage control treatment, in emergency, with Dolphix? External Fixator Frame(CITIEFFE?, Calderara di Reno, Bologna, Italy) permits a stable osteotaxis with minimal soft tissue damage and permit the repair of muscles, blood vessels and nerves with a stable bone and the soft tissue healing with vaccum therapy. 展开更多
关键词 TIBIAL PILON External FIXATION DELTA frame Damage control ANKLE outcomes Open fracture Soft tissue injury
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A novel dynamic frame rate control algorithm for H.264 low-bit-rate video coding
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作者 杨静 Fang Xiangzhong 《High Technology Letters》 EI CAS 2007年第1期53-57,共5页
The goal of this paper is to improve human visual perceptual quality as well as coding efficiency of H. 264 video at low bit rate conditions by adaptively adjusting the number of skipped frames. The encoding frames ar... The goal of this paper is to improve human visual perceptual quality as well as coding efficiency of H. 264 video at low bit rate conditions by adaptively adjusting the number of skipped frames. The encoding frames are selected according to the motion activity of each frame and the motion accumulation of successive frames. The motion activity analysis is based on the statistics of motion vectors and with consider- ation of the characteristics of H. 264 coding standard. A prediction model of motion accumulation is pro- posed to reduce complex computation of motion estimation. The dynamic encoding frame rate control algorithm is applied to both the frame level and the GOB (Group of Macroblocks ) level. Simulation is done to compare the performance of JM76 with the proposed frame level scheme and GOB level scheme. 展开更多
关键词 H.264 motion analysis frame rate control low-bit-rate
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Vibration analysis of maglev three-span rigid frame bridge considering magnetic force
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作者 滕延锋 滕念管 寇新建 《Journal of Southeast University(English Edition)》 EI CAS 2007年第4期571-576,共6页
The dynamic interaction between the maglev vehicle and the three-span rigid frame bridge is discussed. With the consideration of magnetic force, the interaction model is developed. Numerical simulations are performed ... The dynamic interaction between the maglev vehicle and the three-span rigid frame bridge is discussed. With the consideration of magnetic force, the interaction model is developed. Numerical simulations are performed to study the dynamic characteristics of the bridge during vehicle movement along the bridge. The results show that a reasonable value of the linear stiffness ratio of columns to beams is between 2. 0 and 3.0. The dynamic responses of the bridge are aggravated with the decrease in bending rigidity and the increase in vehicle speed and the span ratio of the bridge. It is suggested that a definite way is to control impact coefficients and acceleration in the dynamic design of the bridge. It is unsuitable to adopt the moving load model and the moving mass model in the design. The proposed results can serve in the design of high-speed maglev three-span rigid frame bridges. 展开更多
关键词 maglev transportation system three-span rigid frame bridge vertical vibration magnetic force control system
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浅谈FrameNet框架汉译时的译者术语意识 被引量:3
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作者 柴清华 李茹 由丽萍 《中国科技术语》 2016年第3期5-10,共6页
汉语框架网的建设需要参照FrameNet,因而FrameNet框架汉译是其中必要的一步。由于FrameNet框架会涉及众多"概念名称",所以在FrameNet框架汉译时,译者术语意识通过提供一定程度上的理论指导来加强控制汉语框架网的框架质量。
关键词 译者术语意识 frameNet框架汉译 框架质量控制
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Frame-layer bit allocation for multi-view video coding based on frame complexity estimation 被引量:1
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作者 严涛 安平 +3 位作者 沈礼权 李振纲 王贺 张兆杨 《Journal of Shanghai University(English Edition)》 2010年第1期50-54,共5页
Current multi-view video coding (MVC) reference model in joint video team (JVT) does not provide efficient rate control schemes. This paper presents a rate control algorithm for MVC by improving the quadratic rate... Current multi-view video coding (MVC) reference model in joint video team (JVT) does not provide efficient rate control schemes. This paper presents a rate control algorithm for MVC by improving the quadratic rate-distortion (R-D) model. We reasonably allocate bit-rate among views based on the correlation analysisl The proposed algorithm consists of three levels to control the rate bits more accurately, of which the frame layer allocates bits according to the frame complexity and the temporal activity. Extensive experiments show that the proposed algorithm can control the bit rate efficiently. 展开更多
关键词 multi-view video coding (MVC) rate control bit-allocation rate-distortion model correlation analysis frame complexity
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Voice Control for an Industrial Robot as a Combination of Various Robotic Assembly Process Models 被引量:1
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作者 Svitlana Maksymova Rami Matarneh +1 位作者 Vyacheslav V. Lyashenko Nataliya V. Belova 《Journal of Computer and Communications》 2017年第11期1-15,共15页
Models for the design of assembly processes are considered. Various models for the voice control of an industrial robot are considered: a logical model, semantic networks, a frame model and Petri nets. It is shown tha... Models for the design of assembly processes are considered. Various models for the voice control of an industrial robot are considered: a logical model, semantic networks, a frame model and Petri nets. It is shown that this set of models allows describing the process of designing the technological process for an industrial robot. The logical model of the technological process allows you to define logical relationships. A model based on semantic networks describes the relationship between assembly units in a detail. This allows you to determine the order and method of registration, as well as the mutual orientation of assembly units in the product. The frame model provides the ability to streamline the execution of the build process. A model based on Petri nets allows one to describe the type and sequence of technological transitions. Based on the proposed models, a method of voice control for an industrial robot is developed. The basic principles of voice control for an industrial robot are considered. 展开更多
关键词 Robot VOICE control frame MODEL PETRI NETS Logic MODEL SEMANTIC NETS Robotic Assembly Processes
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Control Effects and Material Parameters of Piezoelectric Smart Moment Controllers
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作者 王军武 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2004年第2期64-66,共3页
The control using piezoelectric smart moment (PSM) controllers for seismically excited structures was studied.The radical principle of PSM controller was introduced firstly and then the different formulae of control s... The control using piezoelectric smart moment (PSM) controllers for seismically excited structures was studied.The radical principle of PSM controller was introduced firstly and then the different formulae of control shear force for different structures were derived with the stiffness ratio of columns taken into consideration.With the active control algorithm based on the theory of modern optimal control,this study proposes a simulative computation on the frame structure and mill structure respectively,and the results indicate that the installation of this smart controller with proper parameters can significantly reduce seismic responses of different structures. The optimal parameters of the damper can be identified through a parameter study. 展开更多
关键词 piezoelectric smart moment controller smart moment controller frame structure mill structure earthquake response active control
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An Improvement of MPEG-4 Rate Control Algorithm
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作者 鲁照华 李华 刘继兴 《Transactions of Tianjin University》 EI CAS 2005年第1期40-43,共4页
Frame skipping in low bit video coding could significantly reduce the visual quality of reconstructed video. At the same time, if the complexity of the video sequence remains high for a long period, then driving up th... Frame skipping in low bit video coding could significantly reduce the visual quality of reconstructed video. At the same time, if the complexity of the video sequence remains high for a long period, then driving up the long term average bit rate, the only resort of MPEG-4 Q2 rate control algorithm results in using a high quantization scale, which shows a poor visual quality of the reconstructed video. This paper analyzes the main causes of frame skipping in current MPEG-4 frame rate control scheme, and presents a new rate control algorithm based on the quadratic R-D model over a CBR channel. Key features of the present work are: 1) the bits allocated to each P-frame or B-frame are in proportion to its distance from the end of this GOP, i.e. more bits are allocated to the frames that are nearer to their reference Ⅰ-frame; 2) the target buffer level is changeable in the GOP, at the end of each GOP(five P-frames or B-frames), the target buffer level is linearly reduced from 1/2 to 1/4 of buffer size, to other frames, the target buffer level is set to 1/2 of buffer size; 3) a selective and judicious use of the reduced resolution mode, in addition to a modulation of the quantization scale parameter, is to control the average long term bit rate. Experimental results with different video sequences of varied complexity, encoded at low bit rates show better efficacy of the proposed algorithm than MPEG-4 Q2 rate control scheme, and the experimental results also show that the improved algorithm has significantly reduced the number of frame skipping, increased the overall PSNR, and improved the perceptual quality. 展开更多
关键词 MPEG-4 rate control reduced resolution frame skipping bit allocation
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Active Vibration Control of Rotating Machines with Active Machine Foot Mounts on Soft Foundations Based on a 3D-Model
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作者 Ulrich Werner 《Journal of Applied Mathematics and Physics》 2021年第1期57-87,共31页
The paper presents a simplified 3D-model for active vibration control of rotating machines with active machine foot mounts on soft foundations, considering static and moment unbalance. After the model is mathematical ... The paper presents a simplified 3D-model for active vibration control of rotating machines with active machine foot mounts on soft foundations, considering static and moment unbalance. After the model is mathematical described in the time domain, it is transferred into the Fourier domain, where the frequencies response functions regarding bearing housing vibrations, foundation vibrations and actuator forces are derived. Afterwards, the mathematical coherences are described in the Laplace domain and a worst case procedure is presented to analyze the vibration stability. For special controller structures in combination with certain feedback strategies, a calculation method is shown, where the controller parameters can be directly implemented into the stiffness matrix, damping matrix and mass matrix. Additionally a numerical example is presented, where the vibration stability and the frequency response functions are analyzed. 展开更多
关键词 Active Vibration control Rotating Machines Actuators Steel frame Foundation
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Error Resilient Video Communication Based on Picture Level Adaptive Frame / Field Coding
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作者 徐巍炜 周凡 陈耀武 《Journal of Donghua University(English Edition)》 EI CAS 2013年第2期103-109,共7页
Packet loss protection method based on picture level adaptive frame /field coding (PAFF)was presented. Firstly,the end-to-end rate-distortion analysis for PAFF on the current frame was performed. Secondly,in order to ... Packet loss protection method based on picture level adaptive frame /field coding (PAFF)was presented. Firstly,the end-to-end rate-distortion analysis for PAFF on the current frame was performed. Secondly,in order to evaluate the severity of error propagation in the following frames,the error propagation intensity and human visual quality sensitivity of different areas were taken into consideration. It was followed by the quantification of relative importance. Finally,the proper coding mode was chosen utilizing an unequal comparison procedure. The simulation results show that the proposed method can improve peak signal-to-noise ratio (PSNR) up to 0. 9 dB and 1. 6 dB comparing with the field only and the dispersed flexible macro-block ordering (FMO)only methods respectively. 展开更多
关键词 error resilience field coding adaptive frame/field coding human visual system error control coding
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Frame complexity optimized selection for H.264/AVC video coding
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作者 Tian Ling Sun Yu +1 位作者 Zhou Yimin Sun Shixin 《High Technology Letters》 EI CAS 2011年第4期383-387,共5页
To improve the coding performance of H.264/AVC, this paper proposes a rate control scheme composed of a novel flame complexity optimized selection and a quantization parameter (QP) value computation approach. First,... To improve the coding performance of H.264/AVC, this paper proposes a rate control scheme composed of a novel flame complexity optimized selection and a quantization parameter (QP) value computation approach. First, it extracts the frame coding complexity from two rate distortion models, and then introduces five statistic modes to estimate the frame coding complexity. An optimal mode is selected according to the coding efficiency. Finally the paper presents a novel QP calculation method for the H.264/AVC rate control. Experimental results show that the proposed algorithra outperforms the algorithm integrated in the 3M model in obtaining precise frame coding complexity, achieving robust buffer control and improving coding quality. And the improving visual quality is high up to 0.90dB for CIF sequences. 展开更多
关键词 frame coding complexity rate control H.264/AVC RD model
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Unknown constrained mechanisms operation based on dynamic interactive control
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作者 Hesheng Wang Bohan Yang Weidong Chen 《CAAI Transactions on Intelligence Technology》 2016年第3期259-271,共13页
In order to operate various constrained mechanisms with assistive robot manipulators, an interactive control algorithm is proposed in this paper. This method decouples motion and force control in the constrained frame... In order to operate various constrained mechanisms with assistive robot manipulators, an interactive control algorithm is proposed in this paper. This method decouples motion and force control in the constrained frame, and modifies the motion velocity online. Firstly, the constrained frame is determined online according to previous motion direction; then the selection matrix is adjusted dynamically, the constrained motion direction is chosen as the driving-axis. Consequently, the driving-axis and non-driving-axis are decoupled; finally, velocity control and impedance control are implied on above axes respectively. The selecting threshold for driving-axis is also varying dynamically to fit different constrained mechanism. Door-opening experiments are conducted to verify the performance of the proposed method. 展开更多
关键词 Unknown constrained mechanism Selection matrix Constrained frame Robot manipulator Impedance control
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中国减污降碳生态环境标准体系研究
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作者 谭玉菲 王宗爽 +3 位作者 赵国华 李艳萍 江梅 武雪芳 《环境污染与防治》 CAS CSCD 北大核心 2024年第9期1340-1345,1371,共7页
中国现行生态环境标准体系以减污治污为核心,与降碳联系不紧密,支撑碳排放权交易、温室气体排放和监测、减污降碳协同控制技术指南等标准缺乏,难以有效支撑美丽中国建设和“双碳”目标实现。为此,在分析国际温室气体和环境污染物协同管... 中国现行生态环境标准体系以减污治污为核心,与降碳联系不紧密,支撑碳排放权交易、温室气体排放和监测、减污降碳协同控制技术指南等标准缺乏,难以有效支撑美丽中国建设和“双碳”目标实现。为此,在分析国际温室气体和环境污染物协同管控政策标准基础上,结合中国减污降碳管理需求,采用分类层次结构及综合标准化法,构建了支撑“市场+行政”温室气体管理模式的减污降碳生态环境标准体系框架。建议提前对计划纳入碳市场的行业制定配额核算核查等相关碳排放权交易标准,对其他行业研究制定协同控制温室气体的污染物排放标准,并制定相关配套标准支撑全链条减污降碳协同管控。 展开更多
关键词 减污降碳 应对气候变化 温室气体 标准体系 框架结构
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预应变SMA⁃TMD对钢框架结构抗震性能影响研究
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作者 姜子钦 刘澜涛 +2 位作者 黄浩宇 王伟 韩伟 《建筑结构》 北大核心 2024年第20期48-52,128,共6页
针对钢结构在地震激励下加速度响应过大的问题,介绍了一种将形状记忆合金(SMA)应用到调谐质量阻尼器(TMD)装置中的解决方案,利用SMA的特性实现有效的自复位和稳定的阻尼,将预应变SMA棒应用到TMD中,提高装置的阻尼性能。通过试验测试及... 针对钢结构在地震激励下加速度响应过大的问题,介绍了一种将形状记忆合金(SMA)应用到调谐质量阻尼器(TMD)装置中的解决方案,利用SMA的特性实现有效的自复位和稳定的阻尼,将预应变SMA棒应用到TMD中,提高装置的阻尼性能。通过试验测试及有限元模拟,研究安装施加预应变SMA-TMD的钢框架抗震性能。结果表明:预应变SMA棒不仅有助于自复位,而且还能大大提高SMA-TMD的等效黏滞阻尼比;经过优化的SMA-TMD装置可以大大降低钢框架的地震动响应,并加快地震能量消耗。 展开更多
关键词 钢框架 形状记忆合金 调谐质量阻尼器 预应变 振动与控制 抗震性能
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