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Initial stiffness and moment resistance of reinforced joint with end-plate connection

Sufang WANG, Yiyi CHEN,

《结构与土木工程前沿(英文)》 2009年 第3卷 第4期   页码 345-351 doi: 10.1007/s11709-009-0054-x

摘要: In beam-to-column joint with bolted end-plate connection, the structural details of column flange reinforced by backing plate and column web panel reinforced by supplementary plate are analyzed. The joint is divided into some basic components, and the initial stiffness of each component is obtained. Especially, the initial stiffness of reinforced components is drawn by theoretical model and finite element analysis. The initial stiffness of reinforced joint can be obtained by assembling the initial stiffness of each component. The design moment resistance of column flange reinforced by backing plate is deduced based on yield line method, and the design moment resistances of other components are deduced based on present codes. The design moment resistance of the reinforced joint is then determined by the minimum of the design moment resistances of all components. By comparison with the results of finite element calculation, it is verified that the method to calculate the initial stiffness of reinforced joint is accurate enough to be used to estimate the rigid behavior of the joint and to make parametric study.

关键词: steel structure     end-plate connection     backing plate     supplementary web plate     initial stiffness     moment resistance    

Investigation of fatigue resistance of fillet-welded tube connection details for sign support structures

Hyungjoo CHOI, Husam NAJM

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 199-214 doi: 10.1007/s11709-019-0592-9

摘要: Stiffened and unstiffened fillet-welded tube-to-transverse plate connection details are widely used for mast-arm and base-plate connections for highway sign structures. However, due to repetitive wind loads, cyclic fatigue stresses are induced and they are the primary source of failure in welded connections at these locations. The resistance of fatigue critical details has been an on-going research topic because of limited experimental results and the variability in existing fatigue testing results. The main objective of this study is to evaluate fatigue resistance of fillet-welded tube connection details by utilizing the advanced fatigue tool in ANSYS Workbench platform. Finite Element (FE) models development and model validation using existing test data was presented. The resulting fatigue resistance from FE analysis was expressed in terms of fatigue life, fatigue damage, and fatigue safety factor to determine the fatigue performance of fillet-welded connections. Existing fatigue test data was grouped to perform a synthetic analysis and then analysis results were provided to determine input data and fatigue limit for the fatigue module. The local stress level at fatigue critical locations was evaluated using a static FE model for different number of stiffeners and boundary conditions. The results of this investigation provides fatigue resistance of fillet-welded connection details in the form of fatigue life, fatigue damage and safety factor for various connection parameters and structural conditions.

关键词: fatigue     weld connections     base plate     fillet welds    

Multi-objective optimization of surface texture for the slipperswash plate interface in EHA pumps

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0704-4

摘要: Well-designed surface textures can improve the tribological properties and the efficiency of the electro-hydrostatic actuator (EHA) pump under high-speed and high-pressure conditions. This study proposes a multi-objective optimization model to obtain the arbitrarily surface textures design of the slipper/swash plate interface for improving the mechanical and volumetric efficiency of the EHA pump. The model is composed of the lubrication film model, the component dynamic model considering the spinning motion, and the multi-objective optimization model. In this way, the arbitrary-shaped surface texture with the best comprehensive effect in the EHA pump is achieved and its positive effects in the EHA pump prototype are verified. Experimental results show a reduction in wear and an improvement in mechanical and volumetric efficiency by 1.4% and 0.8%, respectively, with the textured swash plate compared with the untextured one.

关键词: electro-hydrostatic actuator     axial piston pump     slipper/swash plate interface     multi-objective optimization     surface texture    

Topology-independent end-to-end learning model for improving the voltage profile in microgrids-integrated

《能源前沿(英文)》 2023年 第17卷 第2期   页码 211-227 doi: 10.1007/s11708-022-0847-3

摘要: With multiple microgrids (MGs) integrated into power distribution networks in a distributed manner, the penetration of renewable energy like photovoltaic (PV) power generation surges. However, the operation of power distribution networks is challenged by the issues of multiple power flow directions and voltage security. Accordingly, an efficient voltage control strategy is needed to ensure voltage security against ever-changing operating conditions, especially when the network topology information is absent or inaccurate. In this paper, we propose a novel data-driven voltage profile improvement model, denoted as system-wide composite adaptive network (SCAN), which depends on operational data instead of network topology details in the context of power distribution networks integrated with multiple MGs. Unlike existing studies that realize topology identification and decision-making optimization in sequence, the proposed end-to-end model determines the optimal voltage control decisions in one shot. More specifically, the proposed model consists of four modules, Pre-training Network and modified interior point methods with adversarial networks (Modified IPMAN) as core modules, and discriminator generative adversarial network (Dis-GAN) and Volt convolutional neural network (Volt-CNN) as ancillary modules. In particular, the generator in SCAN is trained by the core modules in sequence so as to form an end-to-end mode from data to decision. Numerical experiments based on IEEE 33-bus and 123-bus systems have validated the effectiveness and efficiency of the proposed method.

关键词: end-to-end learning     microgrids     voltage profile improvement     generative adversarial network    

Risk evaluation for the task transfer of an aircraft maintenance program based on a multielement connection

《工程管理前沿(英文)》 doi: 10.1007/s42524-023-0282-0

摘要: This paper proposes a framework for evaluating the efficacy and suitability of maintenance programs with a focus on quantitative risk assessment in the domain of aircraft maintenance task transfer. The analysis is anchored in the principles of Maintenance Steering Group-3 (MSG-3) logic decision paradigms. The paper advances a holistic risk assessment index architecture tailored for the task transfer of maintenance programs. Utilizing the analytic network process (ANP), the study quantifies the weight interrelationships among diverse variables, incorporating expert-elicited subjective weighting. A multielement connection number-based evaluative model is employed to characterize decision-specific data, thereby facilitating the quantification of task transfer-associated risk through the appraisal of set-pair potentials. Moreover, the paper conducts a temporal risk trend analysis founded on partial connection numbers of varying orders. This analytical construct serves to streamline the process of risk assessment pertinent to maintenance program task transfer. The empirical component of this research, exemplified through a case study of the Boeing 737NG aircraft maintenance program, corroborates the methodological robustness and pragmatic applicability of the proposed framework in the quantification and analysis of mission transfer risk.

关键词: risk evaluation     maintenance steering group     analytic network process     task transfer     maintenance program    

Mouth the mirror of lungs: where does the connection lie?

null

《医学前沿(英文)》 2016年 第10卷 第4期   页码 405-409 doi: 10.1007/s11684-016-0476-5

摘要:

Periodontitis is the chronic destructive disease of the periodontium (Gums) caused by host bacterial interactions. The effect of such host bacterial interactions in oral cavity also evokes a systemic response. Numerous studies have found common mechanisms of destruction for periodontal diseases and other chronic diseases like diabetes mellitus, atherosclerosis, respiratory diseases, and adverse pregnancy outcomes. Oral colonization by respiratory pathogens appears to be a risk factor for development of respiratory diseases and oral interventions aimed at reducing oral bacterial count have resulted in reduced incidence of these reparatory illness. This reflects the importance of oral hygiene among patients with respiratory illness. This review highlights the association between periodontal diseases and respiratory diseases.

关键词: periodontitis     respiratory diseases     acute pneumonia     COPD    

Static behavior of planar intersecting CFST connection in diagrid structure

Ling LI, Xianzhong ZHAO, Ke KE

《结构与土木工程前沿(英文)》 2011年 第5卷 第3期   页码 355-365 doi: 10.1007/s11709-011-0125-7

摘要: Intersecting connection plays an important role in the new diagrid structural system for high-rise buildings. To investigate the static behavior of the intersecting connection of concrete-filled steel tubular (CFST) columns, a typical reduced-scale planner connection specimen is tested under monotonic axial compression. The failure modes, force mechanism and bearing capacity of intersecting CFST connections are analyzed further in the follow-up numerical simulation, considering influences of intersecting angle, elliptical plate and ring plate. Test and simulation results prove that, intersecting connection can develop fully plastic deformation and provide sufficient bearing capacity. Parametric analysis indicates that bearing capacity of planar intersecting CFST connection mainly depends on intersecting angle and thickness of elliptical plate, while the ring plate affects that little. Capacity estimation method for planar intersecting CFST connection is proposed basing on the capacity of the critical section which is located near intersecting center for a distance of steel tube radius, and the design suggestions is provided in the end of this paper.

关键词: diagrid structure     concrete-filled steel tube     planar intersecting connection     experimental research     mechanism analysis    

On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate

Hui Ching FAN, Hong Sen YAN

《机械工程前沿(英文)》 2012年 第7卷 第1期   页码 5-15 doi: 10.1007/s11465-012-0310-y

摘要:

Without modifying the cam contour, a cam mechanism with a variable input speed trajectory offers an alternative solution to flexibly achieve kinematic and dynamic characteristics, and then decrease the follower’s residual vibration. Firstly, the speed trajectory of cam is derived by employing Bezier curve, and motion continuity conditions are investigated. Then the motion characteristics between the plate cam and its roller follower are derived. To analyze the residual vibration, a single degree of freedom dynamic model of the elastic cam-follower system is introduced. Based on the motion equation derived from the dynamic model, the residual vibration of the follower is yielded. The design procedure to improve the kinematic and dynamic motion characteristics is presented and two design examples with discussions are provided. Finally, the simulations of the kinematic and dynamic models by ADAMS are carried out and verified that the design models as well as the performances of the mechanism are feasible.

关键词: cam mechanism     variable input speed     kinematic design     dynamic design     optimal design    

An innovative model for predicting the displacement and rotation of column-tree moment connection under

Mohammad Ali NAGHSH, Aydin SHISHEGARAN, Behnam KARAMI, Timon RABCZUK, Arshia SHISHEGARAN, Hamed TAGHAVIZADEH, Mehdi MORADI

《结构与土木工程前沿(英文)》 2021年 第15卷 第1期   页码 194-212 doi: 10.1007/s11709-020-0688-2

摘要: In this study, we carried out nonlinear finite element simulations to predict the performance of a column-tree moment connection (CTMC) under fire and static loads. We also conducted a detailed parameter study based on five input variables, including the applied temperature, number of flange bolts, number of web bolts, length of the beam, and applied static loads. The first variable is changed among seven levels, whereas the other variables are changed among three levels. Employing the Taguchi method for variables 2–5 and their levels, 9 samples were designed for the parameter study, where each sample was exposed to 7 different temperatures yielding 63 outputs. The related variables for each output are imported for the training and testing of different surrogate models. These surrogate models include a multiple linear regression (MLR), multiple Ln equation regression (MLnER), an adaptive network-based fuzzy inference system (ANFIS), and gene expression programming (GEP). 44 samples were used for training randomly while the remaining samples were employed for testing. We show that GEP outperforms MLR, MLnER, and ANFIS. The results indicate that the rotation and deflection of the CTMC depend on the temperature. In addition, the fire resistance increases with a decrease in the beam length; thus, a shorter beam can increase the fire resistance of the building. The numbers of flanges and web bolts slightly affect the rotation and displacement of the CTMCs at temperatures of above 400°C.

关键词: column-tree moment connection     Finite element model     parametric study     fire     regression models     gene expression programming    

Frequencies of circular plate with concentric ring and elastic edge support

null

《机械工程前沿(英文)》 2014年 第9卷 第2期   页码 168-176 doi: 10.1007/s11465-014-0299-5

摘要:

Exact solutions for the flexural vibrations of circular plates having elastic edge conditions along with rigid concentric ring support have been presented in this paper. Values of frequency parameter for the considered circular plate are computed for different sets of values of elastic rotational and translation restraints and the radius of internal rigid ring support. The results for the first three modes of plate vibrations are computed and are presented in tabular form. The effects of rotational and linear restraints and the radius of the rigid ring support on the vibration behavior of circular plates are studied over a wide range of non-dimensional parametric values. The values of the exact frequency parameter presented in this paper for varying values of restraint parameters and the radius of the rigid ring support can better serve in design and as benchmark solutions to validate the numerical methods obtained by using other methods of solution.

关键词: circular plate     frequency     elastic edge     rigid ring     mode switching    

一种端到端语音合成中的高效解码自注意力网络 Research Article

赵伟1,2,许力1,2

《信息与电子工程前沿(英文)》 2022年 第23卷 第7期   页码 1127-1138 doi: 10.1631/FITEE.2100501

摘要: 自注意力网络由于其并行结构和强大的序列建模能力,被广泛应用于语音合成(TTS)领域。然而,当使用自回归解码方法进行端到端语音合成时,由于序列长度的二次复杂性,其推理速度相对较慢。当部署设备未配备图形处理器(GPU)时,该效率问题更加严重。为解决该问题,提出一种高效解码自注意力网络(EDSA)作为替代。通过一个动态规划解码过程,有效加速TTS模型推理,使其具有线性计算复杂度。基于普通话和英文数据集的实验结果表明,所提EDSA模型在中央处理器(CPU)和GPU上的推理速度分别提高720%和50%,而性能几乎相同。因此,在GPU资源有限的情况下,该方法可使此类模型的部署更加容易。此外,所提模型在域外语言处理上可能比基线Transformer TTS性能更好。

关键词: 高效解码;端到端;自注意力网络;语音合成    

Simulation of grid connection and maximum power point tracking control of brushless doubly-fed generator

Hicham SERHOUD, Djilani BENATTOUS

《能源前沿(英文)》 2013年 第7卷 第3期   页码 380-387 doi: 10.1007/s11708-013-0252-z

摘要: In this paper, based on the analysis of the mathematical model in a common synchronous reference frame of the brushless doubly-fed generator (BDFG), the grid connection strategy and maximum energy extraction control were both analyzed. Besides, the transient simulation of no-load model and generation model of the BDFG have been developed on the MATLAB/Simulink platform. The test results during cutting-in grid confirmed the good dynamic performance of grid synchronization and effective power control approach for the BDFG-based variable speed wind turbines.

关键词: brushless doubly-fed generator (BDFG)     modeling     grid connection control     back-to-back pulse-width modulation (PWM) converter     wind power generation    

Comparison on End-of-Life strategies of WEEE in China based on LCA

Bin Lu, Xiaolong Song, Jianxin Yang, Dong Yang

《环境科学与工程前沿(英文)》 2017年 第11卷 第5期 doi: 10.1007/s11783-017-0994-7

摘要: As the Electrical and Electronic Equipment (EEE) are upgraded more frequently in China, a large quantity of Waste Electrical and Electronic Equipment (WEEE) was and will be generated. It becomes an urgent issue to develop and adopt an effective End-of-Life (EoL) strategy for EEE in order to balance the resource recovery and environmental impacts. In an EoL strategy hierarchy for EEE, reuse strategy is usually deemed to be prior to materials recovery and other strategies. But in practice, the advantages and disadvantages of different strategies are always context-dependent. Therefore, main EoL strategies for EEE in China need to be evaluated in environment and resources aspects from the life cycle perspective. In this study, the obsolete refrigerator and Power Supply Unit (PSU) of desktop PC are both taken as the target products. Life Cycle Assessment (LCA) is applied to assess the environmental impacts of different EoL scenarios in China: Unit Reuse Scenario (URS), Component Reuse Scenario (CRS) and Materials Recovery Scenario (MRS). The LCA results show that the EoL strategies hierarchy is reasonable for the part of computer, but not necessarily suitable for obsolete refrigerators. When the policy makers promote or demote one EoL strategy especially reuse, it is necessary to take subsequent impacts into consideration.

关键词: End-of-Life     Waste electrical and electronic equipment     Life cycle assessment     Reuse    

Effect of eccentricity in reinforced concrete beam-column-slab connection under cyclic loading

Rooh ULLAH, Amjad NASEER, Muhammad FAHIM, Mohammad ASHRAF, Eid BADSHAH

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 390-398 doi: 10.1007/s11709-021-0690-3

摘要: Beam–column connections are one of the most critical elements of reinforced concrete structures, especially in seismically active regions, and have been extensively evaluated experimentally and numerically. However, very limited experimental studies about eccentric reinforced concrete connections including the effect of connected slabs are available. This study presents the experimental results of two half-scale eccentric beam-column-slab connections subjected to quasi-static cyclic loading. The horizontal eccentricity ( ) is maintained at 12.5% and 25% of column width ( ) for specimens 1 and 2, respectively. The damage pattern, performance levels, displacement ductility ( ), energy dissipation, and connection strength and stiffness are compared for both specimens, and the effect of eccentricity is evaluated. It is concluded that the eccentricity has no significant effect on the lateral load carrying capacity; however, the overall strength degradation increases with the increase in eccentricity. Similarly, the elastic stiffness of specimen 2 decreased by 14% as the eccentricity increased from 12.5% to 25%; however, the eccentricity had no significant effect on the overall stiffness degradation. decreased by 43%, and the energy dissipation capacity decreased by 40% in specimen 2 with higher eccentricity. The story drifts corresponding to the performance levels of the life safety (LS) and collapse prevention (CP) were found to be 28% lesser in specimen 2 than in specimen 1.

关键词: corner connection     eccentricity     strength degradation     stiffness degradation     energy dissipation     performance levels    

Linear ultrasonic motor using quadrate plate transducer

Jiamei JIN, Chunsheng ZHAO

《机械工程前沿(英文)》 2009年 第4卷 第1期   页码 88-91 doi: 10.1007/s11465-009-0016-y

摘要: A linear ultrasonic motor using a quadrate plate transducer was developed for precision positioning. This motor consists of two pairs of Pb(Zr,Ti)O piezoelectric ceramic elements, which are piezoelectrically excited into the second-bending mode of the motor stator’s neutral surface in two orthogonal directions, on which the tops of four projections move along an elliptical trajectory, which in turn drives a contacted slider into linear motion via frictional forces. The coincident frequency of the stator is easily obtained for its coincident characteristic dimension in two orthogonal directions. The performance characteristics achieved by the motor are: 1) a maximum linear speed of more than 60 mm/s; 2) a stroke of more than150 mm; 3) a driving force of more than 5.0 N; and 4) a response time of about 2 ms.

关键词: ultrasonic motor     quadrate plate     coincident frequency     alternant contact    

标题 作者 时间 类型 操作

Initial stiffness and moment resistance of reinforced joint with end-plate connection

Sufang WANG, Yiyi CHEN,

期刊论文

Investigation of fatigue resistance of fillet-welded tube connection details for sign support structures

Hyungjoo CHOI, Husam NAJM

期刊论文

Multi-objective optimization of surface texture for the slipperswash plate interface in EHA pumps

期刊论文

Topology-independent end-to-end learning model for improving the voltage profile in microgrids-integrated

期刊论文

Risk evaluation for the task transfer of an aircraft maintenance program based on a multielement connection

期刊论文

Mouth the mirror of lungs: where does the connection lie?

null

期刊论文

Static behavior of planar intersecting CFST connection in diagrid structure

Ling LI, Xianzhong ZHAO, Ke KE

期刊论文

On the improvement design of dynamic characteristics for the roller follower of a variable-speed plate

Hui Ching FAN, Hong Sen YAN

期刊论文

An innovative model for predicting the displacement and rotation of column-tree moment connection under

Mohammad Ali NAGHSH, Aydin SHISHEGARAN, Behnam KARAMI, Timon RABCZUK, Arshia SHISHEGARAN, Hamed TAGHAVIZADEH, Mehdi MORADI

期刊论文

Frequencies of circular plate with concentric ring and elastic edge support

null

期刊论文

一种端到端语音合成中的高效解码自注意力网络

赵伟1,2,许力1,2

期刊论文

Simulation of grid connection and maximum power point tracking control of brushless doubly-fed generator

Hicham SERHOUD, Djilani BENATTOUS

期刊论文

Comparison on End-of-Life strategies of WEEE in China based on LCA

Bin Lu, Xiaolong Song, Jianxin Yang, Dong Yang

期刊论文

Effect of eccentricity in reinforced concrete beam-column-slab connection under cyclic loading

Rooh ULLAH, Amjad NASEER, Muhammad FAHIM, Mohammad ASHRAF, Eid BADSHAH

期刊论文

Linear ultrasonic motor using quadrate plate transducer

Jiamei JIN, Chunsheng ZHAO

期刊论文