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Development of rocking constraint device with vertical damping capacity for three-dimensional base-isolated

《结构与土木工程前沿(英文)》 2023年 第17卷 第3期   页码 350-367 doi: 10.1007/s11709-022-0923-0

摘要: A new rocking constraint device (RCD) is developed for three-dimensional (3D) base-isolated frame structures by connecting a custom-designed cylinder pair to provide vertical damping with replaceable damping components installed outside the cylinders when the superstructure undergoes translational motion, and rocking constraint capacity when the superstructure is susceptible to rocking. Theoretical formulas for calculating the damping and rocking constraint stiffness of the RCD are proposed. Two series of sinusoidal loading tests are conducted at different loading frequencies and amplitudes to verify the damping and rocking constraint performance of the RCD. The test results show that the cylinder without orifices on its piston can provide the desired damping with a replaceable damping component, and that the RCD can effectively suppress rocking. Although the vertical stiffness of an individual cylinder is affected by the location of the replaceable damping component and loading frequency, the average vertical stiffness of the two cylinders, which determines the rocking constraint stiffness of the RCD, is independent of the two factors. Comparisons of the test and theoretical results indicate that the errors of the proposed formulas for calculating the damping and rocking constraint stiffness of the RCD do not exceed 12.9% and 11.0%, respectively.

关键词: three-dimensional isolation     rocking behavior     rocking constraint device     replaceable damping component     sinusoidal test    

Seismic retrofit of existing SRC frames using rocking walls and steel dampers

Akira WADA, Zhe QU, Shojiro MOTOYUI, Hiroyasu SAKATA

《结构与土木工程前沿(英文)》 2011年 第5卷 第3期   页码 259-266 doi: 10.1007/s11709-011-0114-x

摘要: A retrofit of an existing 11-story steel reinforced concrete frame that features the innovative use of post-tensioned rocking walls and shear steel dampers is presented. The main components of the retrofitting plan and important design considerations are described. The retrofitting system is expected to effectively control the deformation pattern of the existing structure and significantly reduce damage to the existing structure during major earthquakes.

关键词: building structure     seismic retrofit     rocking wall     steel damper    

multi-objective design method for seismic retrofitting of existing reinforced concrete frames using pin-supported rocking

Yue CHEN; Rong XU; Hao WU; Tao SHENG

《结构与土木工程前沿(英文)》 2022年 第16卷 第9期   页码 1089-1103 doi: 10.1007/s11709-022-0851-z

摘要: Over the past several decades, a variety of technical ways have been developed in seismic retrofitting of existing reinforced concrete frames (RFs). Among them, pin-supported rocking walls (PWs) have received much attentions to researchers recently. However, it is still a challenge that how to determine the stiffness demand of PWs and assign the value of the drift concentration factor (DCF) for entire systems rationally and efficiently. In this paper, a design method has been exploited for seismic retrofitting of existing RFs using PWs (RF-PWs) via a multi-objective evolutionary algorithm. Then, the method has been investigated and verified through a practical project. Finally, a parametric analysis was executed to exhibit the strengths and working mechanism of the multi-objective design method. To sum up, the findings of this investigation show that the method furnished in this paper is feasible, functional and can provide adequate information for determining the stiffness demand and the value of the DCF for PWs. Furthermore, it can be applied for the preliminary design of these kinds of structures.

关键词: pin-supported rocking wall     reinforced concrete frame     seismic retrofit     stiffness demand     drift concentration factor     multi-objective design     genetic algorithm     Pareto optimal solution    

Technology and system of constraint programming for industry production scheduling

Yarong CHEN, Zailin GUAN, Yunfang PENG, Xinyu SHAO, Muhammad HASSEB

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 455-464 doi: 10.1007/s11465-010-0106-x

摘要: The use of techniques and system of constraint programming enables the implementation of precise, flexible, efficient, and extensible scheduling systems. It has been identified as a strategic direction and dominant form for the application into planning and scheduling of industrial production. This paper systematically introduces the constraint modeling and solving technology for production scheduling problems, including various real-world industrial applications based on the Chip system of Cosytec Company. We trend of some concrete technology, such as modeling, search, constraint propagation, consistency, and optimization of constraint programming for scheduling problems. As a result of the application analysis, a generic application framework for real-life scheduling based on commercial constraint propagation (CP) systems is proposed.

关键词: constraint programming     production scheduling     constraint propagation     search     consistency     optimization    

Efficient detection methods for amplify-and-forward relay-aided device-to-device systems with full-rate Article

Kang-li ZHANG, Cong ZHANG, Fang-lin GU, Jian WANG

《信息与电子工程前沿(英文)》 2017年 第18卷 第6期   页码 788-795 doi: 10.1631/FITEE.1700018

摘要: 中继辅助设备到设备通信是下一代蜂窝网络中一项极具潜力的技术。研究了适用于配置多天线的放大转发中继辅助设备到设备通信系统的不同传输方案。为了解决基于全速率空时块码传输方案的传统最大似然检测算法复杂度高的问题,文中提出两种低复杂度检测方法,分别为采用最大似然合并算法的检测方法和采用联合条件最大似然检测器的检测方法。特别是,所提的基于联合条件最大似然检测器的检测方法,能够通过牺牲一定的存储空间换取较好的并行处理能力。仿真结果表明:针对采用全速率空时块码传输方案提出的两种检测方法,能够获得与传统最大似然检测方法近乎相同的误符号率,但所提检测方法复杂度更低;同时,采用基于全速率空时块码的传输方案比复用传输方案具有更优的误码性能。仿真结果还进一步验证了对所提检测方法的分集增益分析。

关键词: 设备到设备通信;中继;检测;全速率空时块码    

Recent development in low-constraint fracture toughness testing for structural integrity assessment of

Jidong KANG, James A. GIANETTO, William R. TYSON

《机械工程前沿(英文)》 2018年 第13卷 第4期   页码 546-553 doi: 10.1007/s11465-018-0501-2

摘要:

Fracture toughness measurement is an integral part of structural integrity assessment of pipelines. Traditionally, a single-edge-notched bend (SE(B)) specimen with a deep crack is recommended in many existing pipeline structural integrity assessment procedures. Such a test provides high constraint and therefore conservative fracture toughness results. However, for girth welds in service, defects are usually subjected to primarily tensile loading where the constraint is usually much lower than in the three-point bend case. Moreover, there is increasing use of strain-based design of pipelines that allows applied strains above yield. Low-constraint toughness tests represent more realistic loading conditions for girth weld defects, and the corresponding increased toughness can minimize unnecessary conservatism in assessments. In this review, we present recent developments in low-constraint fracture toughness testing, specifically using single-edge-notched tension specimens, SENT or SE(T). We focus our review on the test procedure development and automation, round-robin test results and some common concerns such as the effect of crack tip, crack size monitoring techniques, and testing at low temperatures. Examples are also given of the integration of fracture toughness data from SE(T) tests into structural integrity assessment.

关键词: fracture toughness     constraint effect     single-edge-notched tension test     pipeline     structural integrity assessment    

Design method and verification of a hybrid prosthetic mechanism with energy-damper clutchable device

《机械工程前沿(英文)》 2021年 第16卷 第4期   页码 747-764 doi: 10.1007/s11465-021-0644-4

摘要: Transfemoral amputees (TAs) have difficulty in mobility during walking, such as restricted movement of lower extremity and body instability, yet few transfemoral prostheses have explored human-like multiple motion characteristics by simple structures to fit the kinesiology, biomechanics, and stability of human lower extremity. In this work, the configurations of transfemoral prosthetic mechanism are synthesized in terms of human lower-extremity kinesiology. A hybrid transfemoral prosthetic (HTP) mechanism with multigait functions is proposed to recover the gait functions of TAs. The kinematic and mechanical performances of the designed parallel mechanism are analyzed to verify their feasibility in transfemoral prosthetic mechanism. Inspired by motion–energy coupling relationship of the knee, a wearable energy-damper clutched device that can provide energy in knee stance flexion to facilitate the leg off from the ground and can impede the leg’s swing velocity for the next stance phase is proposed. Its co-operation with the springs in the prismatic pairs enables the prosthetic mechanism to have the energy recycling ability under the gait rhythm of the knee joint. Results demonstrate that the designed HTP mechanism can replace the motion functions of the knee and ankle to realize its multimode gait and effectively decrease the peak power of actuators from 94.74 to 137.05 W while maintaining a good mechanical adaptive stability.

关键词: hybrid transfemoral prosthetic mechanism     energy recycling     wearable mechanical clutched device     mechanical adaptive stability    

Research on constraint-based virtual assembly technologies

YANG Rundang, WU Dianliang, FAN Xiumin, YAN Juanqi

《机械工程前沿(英文)》 2007年 第2卷 第2期   页码 243-249 doi: 10.1007/s11465-007-0043-5

摘要: To realize a constraint-based virtual assembly operation, the unified representations of the assembly constraint, the equivalent relation between the constraint and the degree of freedom (DOF), and the movement DOF reduction in a virtual environment are proposed. Several algorithms about the constraint treatment are submitted. First, the automatic recognition algorithm based on the assembly relation is used to determine the position and orientation relation between two geometry elements of constraint whether they meet the given errors. Second, to satisfy the new constraint, according to the positing solving algorithm, the position and orientation of an active part are modified with minimal adjustment after the part has satisfied the affirmed constraints. Finally, the algorithm of movement navigation based on the generalized coordinate system is put forward, and the part movement is guided. These algorithms have been applied to the integrated virtual assembly environment (IVAE) system. Experiments have indicated that these algorithms have well supported constraint treatments in the IVAE and realized the closer combination of the virtual and the real assembly processes.

关键词: movement DOF     recognition algorithm     assembly     orientation     combination    

Topology optimization of transient problem with maximum dynamic response constraint using SOAR scheme

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 593-606 doi: 10.1007/s11465-021-0636-4

摘要: This paper proposes a novel method for the continuum topology optimization of transient vibration problem with maximum dynamic response constraint. An aggregated index in the form of an integral function is presented to cope with the maximum response constraint in the time domain. The density filter solid isotropic material with penalization method combined with threshold projection is developed. The sensitivities of the proposed index with respect to design variables are conducted. To reduce computational cost, the second-order Arnoldi reduction (SOAR) scheme is employed in transient analysis. Influences of aggregate parameter, duration of loading period, interval time, and number of basis vectors in the SOAR scheme on the final designs are discussed through typical examples while unambiguous configuration can be achieved. Through comparison with the corresponding static response from the final designs, the optimized results clearly demonstrate that the transient effects cannot be ignored in structural topology optimization.

关键词: topology optimization     solid isotropic material with penalization     transient response     aggregation function     second-order Arnoldi reduction    

Experiment and optimal design of a collection device for a residual plastic film baler

Qi NIU,Xuegeng CHEN,Chao JI,Jie WU

《农业科学与工程前沿(英文)》 2015年 第2卷 第4期   页码 347-354 doi: 10.15302/J-FASE-2015077

摘要: It is imperative to carry out research on residual plastic film collection technology to solve the serious problem of farmland pollution. The residual plastic film baler was designed as a package for film strip collection, cleaning and baling. The collection device is a core component of the baler. Response surface analysis was used in this study to optimize the structure and working parameters for improving the collection efficiency of residual film and the impurity of film package. The results show that the factors affecting the collection rate of residual film and the impurity of the film package are the speed ratio ( ) between the trash removal roller and eccentric collection mechanism, the number ( ) and the mounting angle ( ) of spring teeth in the same revolution plane. For the collection rate, the importance of the three factors are in the order, . Meanwhile, for the impurity, the importance of three factors are in the order, . When the speed ratio, the mounting angle and the number of spring teeth was set at 1.6°, 45°, and 8°, respectively, the collection rate of residual film was 88.9% and the impurity of residual film package was 14.2% for the baler.

关键词: residual film     collection device     collection rate of residual film     impurity of film package     optimization     baler    

Fast removal of ocular artifacts from electroencephalogram signals using spatial constraint independent

Bang-hua YANG,Liang-fei HE,Lin LIN,Qian WANG

《信息与电子工程前沿(英文)》 2015年 第16卷 第6期   页码 486-496 doi: 10.1631/FITEE.1400299

摘要: Ocular artifacts cause the main interfering signals within electroencephalogram (EEG) signal measurements. An adaptive filter based on reference signals from an electrooculogram (EOG) can reduce ocular interference, but collecting EOG signals during a long-term EEG recording is inconvenient and uncomfortable for the subject. To remove ocular artifacts from EEG in brain-computer interfaces (BCIs), a method named spatial constraint independent component analysis based recursive least squares (SCICA-RLS) is proposed. The method consists of two stages. In the first stage, independent component analysis (ICA) is used to decompose multiple EEG channels into an equal number of independent components (ICs). Ocular ICs are identified by an automatic artifact detection method based on kurtosis. Then empirical mode decomposition (EMD) is employed to remove any cerebral activity from the identified ocular ICs to obtain exact artifact ICs. In the second stage, first, SCICA applies exact artifact ICs obtained in the first stage as a constraint to extract artifact ICs from the given EEG signal. These extracted ICs are called spatial constraint ICs (SC-ICs). Then the RLS based adaptive filter uses SC-ICs as reference signals to reduce interference, which avoids the need for parallel EOG recordings. In addition, the proposed method has the ability of fast computation as it is not necessary for SCICA to identify all ICs like ICA. Based on the EEG data recorded from seven subjects, the new approach can lead to average classification accuracies of 3.3% and 12.6% higher than those of the standard ICA and raw EEG, respectively. In addition, the proposed method has 83.5% and 83.8% reduction in time-consumption compared with the standard ICA and ICA-RLS, respectively, which demonstrates a better and faster OA reduction.

关键词: Ocular artifacts     Electroencephalogram (EEG)     Electrooculogram (EOG)     Brain-computer interface (BCI)     Spatial constraint independent component analysis based recursive least squares (SCICA-RLS)    

A novel flow electrode capacitive deionization device with spindle-shaped desalting chamber

《环境科学与工程前沿(英文)》 2023年 第18卷 第4期 doi: 10.1007/s11783-024-1800-y

摘要:

● A spindle-shaped influent chamber was designed and equipped in FCDI system.

关键词: Spindle-shaped chamber     Desalination performance     Flow electrode capacitive deionization    

工程监理委托代理关系中激励约束与参与约束的研究

秦旋

《中国工程科学》 2007年 第9卷 第4期   页码 45-49

摘要:

基于委托-代理理论对工程监理委托-代理关系中的激励约束与参与约束进行若干拓展研究,与参 与约束(IR)相比,激励相容约束(IC)更为重要,一个机制不满足激励约束,那将是一个无效机制。业主想要 提高工程监理制度的运作效率,就必须通过相应的激励措施诱使工程师努力工作,使“道德风险”得以抑制, 为我国工程监理制度的健康发展提供了有益的启示。

关键词: 工程监理     业主     工程师     委托代理     激励相容约束     参与约束    

Enhancing power generation of piezoelectric bimorph device through geometrical optimization

Action NECHIBVUTE,Albert CHAWANDA,Pearson LUHANGA

《能源前沿(英文)》 2015年 第9卷 第2期   页码 246-246 doi: 10.1007/s11708-015-0360-z

Behaviour of self-centring shear walls——A state of the art review

《结构与土木工程前沿(英文)》 2023年 第17卷 第1期   页码 53-77 doi: 10.1007/s11709-022-0850-0

摘要: The application of unbonded post-tensioning (PT) in structural walls has led to the development of advanced self-centring (rocking) shear wall systems that has significant advantages, including accelerated construction due to the incorporation of prefabricated elements and segmental construction for different materials (e.g., concrete, masonry, and timber), reduced residual drifts, and little damage upon extreme seismic and wind loads. Concrete, masonry, and timber are often used for the construction of unbonded PT structural wall systems. Despite extensive research since the 1980s, there are no well-established design guidelines available on the shear wall configuration with the required energy dissipation system, joint’s locations and acceptance criteria for shear sliding, confinement, seismic performance factors, PT loss, PT force range and residual drifts of shear walls subjected to lateral loads. In this research a comprehensive state-of-the-art literature review was performed on self-centring shear wall system. An extensive study was carried out to collect a database of 100 concrete, masonry, and self-centring shear wall tests from the literature. The established database was then used to review shear walls’ configurations, material, and components to benchmark requirements applicable for design purposes. The behaviour of concrete, masonry and timber shear walls were compared and critically analysed. The general behaviour, force-displacement performance of the walls, ductility, and seismic response factors, were critically reviewed and analysed for different self-centring wall systems to understand the effect of different parameters including configurations of the walls, material used for construction of the wall (concrete, masonry, timber) and axial stress ratio. The outcome of this research can be used to better understand the behaviour of self-centring wall system in order to develop design guidelines for such walls.

关键词: self-centring shear walls     rocking walls     energy dissipation     seismic performance factors     PT loss     residual drift    

标题 作者 时间 类型 操作

Development of rocking constraint device with vertical damping capacity for three-dimensional base-isolated

期刊论文

Seismic retrofit of existing SRC frames using rocking walls and steel dampers

Akira WADA, Zhe QU, Shojiro MOTOYUI, Hiroyasu SAKATA

期刊论文

multi-objective design method for seismic retrofitting of existing reinforced concrete frames using pin-supported rocking

Yue CHEN; Rong XU; Hao WU; Tao SHENG

期刊论文

Technology and system of constraint programming for industry production scheduling

Yarong CHEN, Zailin GUAN, Yunfang PENG, Xinyu SHAO, Muhammad HASSEB

期刊论文

Efficient detection methods for amplify-and-forward relay-aided device-to-device systems with full-rate

Kang-li ZHANG, Cong ZHANG, Fang-lin GU, Jian WANG

期刊论文

Recent development in low-constraint fracture toughness testing for structural integrity assessment of

Jidong KANG, James A. GIANETTO, William R. TYSON

期刊论文

Design method and verification of a hybrid prosthetic mechanism with energy-damper clutchable device

期刊论文

Research on constraint-based virtual assembly technologies

YANG Rundang, WU Dianliang, FAN Xiumin, YAN Juanqi

期刊论文

Topology optimization of transient problem with maximum dynamic response constraint using SOAR scheme

期刊论文

Experiment and optimal design of a collection device for a residual plastic film baler

Qi NIU,Xuegeng CHEN,Chao JI,Jie WU

期刊论文

Fast removal of ocular artifacts from electroencephalogram signals using spatial constraint independent

Bang-hua YANG,Liang-fei HE,Lin LIN,Qian WANG

期刊论文

A novel flow electrode capacitive deionization device with spindle-shaped desalting chamber

期刊论文

工程监理委托代理关系中激励约束与参与约束的研究

秦旋

期刊论文

Enhancing power generation of piezoelectric bimorph device through geometrical optimization

Action NECHIBVUTE,Albert CHAWANDA,Pearson LUHANGA

期刊论文

Behaviour of self-centring shear walls——A state of the art review

期刊论文