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Regional seismic-damage prediction of buildings under mainshock–aftershock sequence

Xinzheng LU, Qingle CHENG, Zhen XU, Chen XIONG

《工程管理前沿（英文）》 2021年 第8卷 第1期   页码 122-134 doi: 10.1007/s42524-019-0072-x

摘要： Strong aftershocks generally occur following a significant earthquake. Aftershocks further damage buildings weakened by mainshocks. Thus, the accurate and efficient prediction of aftershock-induced damage to buildings on a regional scale is crucial for decision making for post-earthquake rescue and emergency response. A framework to predict regional seismic damage of buildings under a mainshock–aftershock (MS–AS) sequence is proposed in this study based on city-scale nonlinear time-history analysis (THA). Specifically, an MS–AS sequence-generation method is proposed to generate a potential MS–AS sequence that can account for the amplification, spectrum, duration, magnitude, and site condition of a target area. Moreover, city-scale nonlinear THA is adopted to predict building seismic damage subjected to MS–AS sequences. The accuracy and reliability of city-scale nonlinear THA for an MS–AS sequence are validated by as-recorded seismic responses of buildings and simulation results in published literature. The town of Longtoushan, which was damaged during the Ludian earthquake, is used as a case study to illustrate the detailed procedure and advantages of the proposed framework. The primary conclusions are as follows. (1) Regional seismic damage of buildings under an MS–AS sequence can be predicted reasonably and accurately by city-scale nonlinear THA. (2) An MS–AS sequence can be generated reasonably by the proposed MS–AS sequence-generation method. (3) Regional seismic damage of buildings under different MS–AS scenarios can be provided efficiently by the proposed framework, which in turn can provide a useful reference for earthquake emergency response and scientific decision making for earthquake disaster relief.

关键词： regional seismic damage prediction     city-scale nonlinear time-history analysis     mainshock–aftershock sequence     multiple degree-of-freedom (MDOF) model     2014 Ludian earthquake    

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Error analysis and optimization of a 3-degree of freedom translational Parallel Kinematic Machine

null

《机械工程前沿（英文）》 2014年 第9卷 第2期   页码 120-129 doi: 10.1007/s11465-014-0300-3

摘要：

In this paper, error modeling and analysis of a typical 3-degree of freedom translational Parallel Kinematic Machine is presented. This mechanism provides translational motion along the Cartesian X-, Y- and Z- axes. It consists of three limbs each having an arm and forearm with prismatic-revolute-revolute-revolute joints. The moving or tool platform maintains same orientation in the entire workspace due to its joint arrangement. From inverse kinematics, the joint angles for a given position of tool platform necessary for the error modeling and analysis are obtained. Error modeling is done based on the differentiation of the inverse kinematic equations. Variation of pose errors along X, Y and Z directions for a set of dimensions of the parallel kinematic machine is presented. A non-dimensional performance index, namely, global error transformation index is used to study the influence of dimensions and its corresponding global maximum pose error is reported. An attempt is made to find the optimal dimensions of the Parallel Kinematic Machine using Genetic Algorithms in MATLAB. The methodology presented and the results obtained are useful for predicting the performance capability of the Parallel Kinematic Machine under study.

关键词： translational Parallel Kinematic Machine     error modeling     global error transformation index    

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On the location of the secondary instantaneous poles in two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

《机械工程前沿（英文）》 2014年 第9卷 第1期   页码 34-40 doi: 10.1007/s11465-014-0290-1

摘要：

As the instant centers in planar mechanisms, the instantaneous poles (or instant poles, in brief) can be used for kinematic analysis in spherical mechanisms. One of the mandatory steps in this analysis is the determination of the location of these poles. This paper presents a theorem showing analytically that the locus of an unknown secondary instant pole in two-degree-of-freedom (2-DOF) spherical mechanisms is a great circle (GC). The exact location of the pole on its GC is obtained based on the configuration of the mechanism and velocity ratio of the two inputs. Moreover, using the results of the theorem, a geometrical technique is presented to determine the GC of the pole.

关键词： spherical mechanisms     instantaneous poles     great circle     angular velocity    

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Stiffness of a 3-degree of freedom translational parallel kinematic machine

null

《机械工程前沿（英文）》 2014年 第9卷 第3期   页码 233-241 doi: 10.1007/s11465-014-0312-z

摘要：

In this paper, a typical 3-degree of freedom (3-DOF) translational parallel kinematic machine (PKM) is studied and analyzed whose tool platform has only translations along X-, Y- and Z-axes. It consists of three limbs, each of which have arm and forearm with prismatic-revolute-revolute-revolute (PRRR) joints. Inverse kinematics analysis is carried out to find the slider coordinates and joint angles for a given position of tool platform. Stiffness modeling is done based on the compliance matrices of arm and forearm of each limb. Using the stiffness modeling the variations of minimum and maximum translational stiffness in the workspace are analyzed. For various architectural parameters of the 3-DOF PKM the tendency of variations on the minimum and maximum stiffness over the entire workspace is studied; and also the deflections of the tool platform along X, Y, and Z directions with respect to various forces are presented.

关键词： 3-DOF translational PKM     inverse kinematics     stiffness modeling     translational stiffness    

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Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism

Jialun YANG, Feng GAO,

《机械工程前沿（英文）》 2009年 第4卷 第4期   页码 379-385 doi: 10.1007/s11465-009-0075-0

摘要： Singularity analysis plays an important role in the design of robots, especially for parallel robots. In this paper, the direct and inverse kinematics of an orthogonal spherical two-degree-of-freedom parallel mechanism is proposed based on the modified Euler angles. All the singular poses of the mechanism are achieved through the direct kinematic analysis. Self-motions, which are different from the general spherical 5 parallel mechanisms, are also discussed. Singularity loci in the joint space and Cartesian space are plotted according to the Jacobin of the mechanism. Result shows that the singularity loci at the joint space are two circles and one line, whereas at the Cartesian space are a circle.

关键词： 2-DOF orthogonal spherical parallel mechanism     singularity loci     self-motions    

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A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

《机械工程前沿（英文）》 2014年 第9卷 第4期   页码 344-353 doi: 10.1007/s11465-014-0320-z

摘要：

This paper is a detailed exploration of instantaneous poles for a class of two-degree-of-freedom (two-DOF) spherical mechanisms (SMs) with seven links or bars. For two-DOF SMs, the secondary instantaneous poles (the ones which cannot be found by direct inspection) must lie on the specified great circles. For many of these mechanisms, however, some of these great circles cannot be obtained by a direct application of Aronhold-Kennedy theorem. This paper presents geometrical and analytical techniques to locate these unknown great circles for three topologies of seven-bar two-DOF SMs.

关键词： spherical mechanisms     instantaneous poles     Aronhold-Kennedy theorem     great circles     pencil of meridian    

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PRESS-based EFOR algorithm for the dynamic parametrical modeling of nonlinear MDOF systems

Haopeng LIU, Yunpeng ZHU, Zhong LUO, Qingkai HAN

《机械工程前沿（英文）》 2018年 第13卷 第3期   页码 390-400 doi: 10.1007/s11465-017-0459-5

摘要：

In response to the identification problem concerning multi-degree of freedom (MDOF) nonlinear systems, this study presents the extended forward orthogonal regression (EFOR) based on predicted residual sums of squares (PRESS) to construct a nonlinear dynamic parametrical model. The proposed parametrical model is based on the non-linear autoregressive with exogenous inputs (NARX) model and aims to explicitly reveal the physical design parameters of the system. The PRESS-based EFOR algorithm is proposed to identify such a model for MDOF systems. By using the algorithm, we built a common-structured model based on the fundamental concept of evaluating its generalization capability through cross-validation. The resulting model aims to prevent over-fitting with poor generalization performance caused by the average error reduction ratio (AERR)-based EFOR algorithm. Then, a functional relationship is established between the coefficients of the terms and the design parameters of the unified model. Moreover, a 5-DOF nonlinear system is taken as a case to illustrate the modeling of the proposed algorithm. Finally, a dynamic parametrical model of a cantilever beam is constructed from experimental data. Results indicate that the dynamic parametrical model of nonlinear systems, which depends on the PRESS-based EFOR, can accurately predict the output response, thus providing a theoretical basis for the optimal design of modeling methods for MDOF nonlinear systems.

关键词： MDOF     dynamic parametrical model     NARX model     PRESS-based EFOR     cantilever beam    

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三自由度混合磁轴承无模型自适应控制系统 Article

Ye YUAN, Yu-kun SUN, Qian-wen XIANG, Yong-hong HUANG, Zhi-ying ZHU

《信息与电子工程前沿（英文）》 2017年 第18卷 第12期   页码 2035-2045 doi: 10.1631/FITEE.1700324

摘要： 由于气隙磁场分布不均以及未建模动态性，数学模型不再适用于磁力轴承系统。基于错误数学模型的系统控制会表现出低响应和高颤动。为解决这一问题，本文提出一种三自由度混合磁轴承无模型自适应控制系统。该控制系统仅与控制电流和轴承的平衡位置有关。其参数估计算法的设计与模型无关，直接基于输入和输出数据的伪偏导数。本文通过不同直径的辅助轴承分析了三自由度混合磁轴承转子悬浮区域,以及通过两种不同的操作系统具体分析无模型自适应控制系统的可行性。模拟和实验结果表明，该三自由度混合磁轴承无模型自适应控制系统具有响应速度快，稳态误差小，和稳定性好等优势。

关键词： 模型自适应控制；混合磁轴承；非线性区域；快速响应；高稳定性    

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Development of dimensionless P-I diagram for curved SCS sandwich shell subjected to uniformly distributed blast pressure

Yonghui WANG, Ximei ZHAI

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1432-1445 doi: 10.1007/s11709-019-0566-y

摘要： The curved steel-concrete-steel (SCS) sandwich shell was recently proposed to resist blast loading and it showed better blast resistant performance as compared to flat SCS sandwich shell via developing compressive force along the shell. In this paper, a dimensionless Pressure-Impulse (P-I) diagram was constructed as a convenient tool to predict the damage level of curved SCS sandwich shell subjected to uniformly distributed blast loading. The curved SCS sandwich shell was equivalent to a single-degree-of-freedom (SDOF) system and the equation of motion was established by employing the Lagrange’s equation. To construct the dimensionless P-I diagram, the energy balance method was utilized to yield the pressure and impulse asymptotes and the responses in the dynamic response regime were obtained via employing the SDOF method. Then, the finite element method was employed to validate the developed dimensionless P-I diagram. Finally, the procedures of using the constructed dimensionless P-I diagram to quickly conduct the blast resistant design of curved SCS sandwich shell were presented.

关键词： blast loading     curved steel-concrete-steel sandwich shell     Pressure-Impulse diagram     single-degree-of-freedom method     finite element analysis    

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Analysis of synergy degree and its influencing factors in hydropower EPC project management

Jiwei ZHU, Hua GAO, Jiangrui WANG

《工程管理前沿（英文）》 2021年 第8卷 第3期   页码 402-411 doi: 10.1007/s42524-020-0098-0

摘要： The use of engineering procurement construction (EPC) mode is currently a trend in hydropower engineering construction. The clarification of the internal relationship between hydropower EPC projects and the realization of synergy has great significance in improving management efficiency and implementation effect. In this work, a three-dimensional system and a system model of hydropower EPC project management synergy are constructed. The mechanism and factors that influence the degree of management synergy are analyzed on the basis of management synergy theory. Furthermore, the evaluation index system and the degree of synergy model are established, and grey relational analysis is utilized to identify the key factors that affect the synergy degree. Thus, this study aims to facilitate the hydropower EPC project management synergy, provide a quantitative method for synergy degree evaluation, and propose corresponding promotion strategies. Results show that the order degree of each subsystem presents a steady upward trend. Specifically, the order degree of the subsystem at the trial operation stage is low, which is the major restriction on the further improvement of the synergy degree of EPC project management. The key factors in improving the synergy level of hydropower EPC project management are mainly concentrated in the information and organization synergy subsystems, including the construction degree of information platform, the performance of functions, the timeliness of information transfer, and the functions of the information platform.

关键词： hydropower project     EPC mode     synergy degree model     grey relational analysis    

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An assessment of surrogate fuel using Bayesian multiple kernel learning model in sight of sooting tendency

《能源前沿（英文）》 2022年 第16卷 第2期   页码 277-291 doi: 10.1007/s11708-021-0731-6

摘要： An integrated and systematic database of sooting tendency with more than 190 kinds of fuels was obtained through a series of experimental investigations. The laser-induced incandescence (LII) method was used to acquire the 2D distribution of soot volume fraction, and an apparatus-independent yield sooting index (YSI) was experimentally obtained. Based on the database, a novel predicting model of YSI values for surrogate fuels was proposed with the application of a machine learning method, named the Bayesian multiple kernel learning (BMKL) model. A high correlation coefficient (0.986) between measured YSIs and predicted values with the BMKL model was obtained, indicating that the BMKL model had a reliable and accurate predictive capacity for YSI values of surrogate fuels. The BMKL model provides an accurate and low-cost approach to assess surrogate performances of diesel, jet fuel, and biodiesel in terms of sooting tendency. Particularly, this model is one of the first attempts to predict the sooting tendencies of surrogate fuels that concurrently contain hydrocarbon and oxygenated components and shows a satisfying matching level. During surrogate formulation, the BMKL model can be used to shrink the surrogate candidate list in terms of sooting tendency and ensure the optimal surrogate has a satisfying matching level of soot behaviors. Due to the high accuracy and resolution of YSI prediction, the BMKL model is also capable of providing distinguishing information of sooting tendency for surrogate design.

关键词： sooting tendency     yield sooting index     Bayesian multiple kernel learning     surrogate assessment     surrogate formulation    

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二自由度精确解耦离散复矢量永磁同步电机电流控制器 None

Meng WANG, Jia-qiang YANG, Xiang ZHANG, Chang-sheng ZHU

《信息与电子工程前沿（英文）》 2018年 第19卷 第4期   页码 569-581 doi: 10.1631/FITEE.1601390

摘要： 电流控制器性能对永磁同步电机驱动的影响至关重要，然而，在数字处理器中采用传统的连续域电流控制器不能使系统达到完全解耦，这使得电流控制器性能会随电机转速而变化。为提高电流控制器性能，提出一种利用精确离散复矢量模型在离散域直接设计电流控制器的方法。首先，针对变流器输出电压和电机反电势的不同特性推导出永磁同步电机的精确离散模型。然后，根据该模型设计出三阶形式精确解耦二自由度电流控制器，该控制器在配置系统闭环极点时自由度更高。针对两种不同的对消零极点位置选取方案，借助复矢量根轨迹和灵敏度函数对其抗干扰性和参数敏感度进行考察，结果表明两种方案各有优势。最后，在2.5 kW永磁同步电机实验台上验证了所提电流控制器设计方法的有效性。

关键词： 永磁同步电机；离散电流控制器；复矢量    

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Iterative finite element model of nonlinear viscoplastic analyses for blended granular porous media

WU Yuching, ZHU Cimian

《结构与土木工程前沿（英文）》 2007年 第1卷 第4期   页码 464-473 doi: 10.1007/s11709-007-0063-6

摘要： The iterative finite element model, in which an element is used to represent a single particle, is generated to analyze the global behavior of multiple-material aggregates of materially nonlinear viscoplastic particles. The genera

关键词： nonlinear viscoplastic     iterative     behavior     multiple-material    

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六自由度光栅干涉仪中的无偏溯源角表达法 Research Article

常笛1,2,胡鹏程1,2,谭久彬1,2

《信息与电子工程前沿（英文）》 2021年 第22卷 第12期   页码 1551-1684 doi: 10.1631/FITEE.2000432

摘要： 光栅姿态角表达方法是六自由度光栅干涉测量的重要课题，但仅有少量相关研究。目前，广泛用于航空航天、导航和机器人领域的导航角（roll-pitch-yaw）被引入六自由度光栅干涉测量领域。然而，因导航角存在固有旋转顺序，在描述绕多个测量轴的复杂旋转时会引起溯源偏差，且该偏差随光栅偏摆角度增加而增大，并不符合干涉系统中的精确定义。基于机器人领域的融合角（fused angles）表达法，本文提出“无偏溯源角（fused-like angles）”表达法，因无偏溯源角不会引起溯源偏差，更加符合光栅干涉仪中的定义，从而更适合六自由度测量。提出的无偏溯源角已应用于六自由度光栅干涉的运动模型和解耦算法研究。

关键词： 无偏溯源角；光栅干涉仪；六自由度测量；角度表达方法    

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论正态云模型的普适性

李德毅,刘常昱

《中国工程科学》 2004年 第6卷 第8期   页码 28-34

摘要：

分布函数是分析随机现象的重要工具，正态分布是最重要的概率分布，在自然科学和社会科学中应用广泛；隶属函数是模糊集合的基石，正态隶属函数也有广泛的应用。但是，精确确定一个模糊概念的隶属函数已经成为模糊学应用的瓶颈。云模型把随机性和模糊性结合起来，用数字特征熵，揭示随机性与模糊性的关联性，并用来表示一个定性概念的粒度。正态云模型通过期望、熵和超熵构成的特定结构发生器，生成定性概念的定量转换值，体现概念的不确定性。这种特定结构不但放宽了形成正态分布的前提条件，而且把精确确定隶属函数放宽到构造正态隶属度分布的期望函数，因而更具有普遍适用性，更简单、直接地完成了定性与定量之间的相互转换过程。

关键词： 正态分布函数     隶属度     正态云模型     概念粒度     普适性    

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标题 作者 时间 类型 操作

Regional seismic-damage prediction of buildings under mainshock–aftershock sequence

Xinzheng LU, Qingle CHENG, Zhen XU, Chen XIONG

期刊论文

Error analysis and optimization of a 3-degree of freedom translational Parallel Kinematic Machine

null

期刊论文

On the location of the secondary instantaneous poles in two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

期刊论文

Stiffness of a 3-degree of freedom translational parallel kinematic machine

null

期刊论文

Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism

Jialun YANG, Feng GAO,

期刊论文

A survey of instantaneous poles for a class of two-degree-of-freedom spherical mechanisms

Soheil ZARKANDI

期刊论文

PRESS-based EFOR algorithm for the dynamic parametrical modeling of nonlinear MDOF systems

Haopeng LIU, Yunpeng ZHU, Zhong LUO, Qingkai HAN

期刊论文

三自由度混合磁轴承无模型自适应控制系统

Ye YUAN, Yu-kun SUN, Qian-wen XIANG, Yong-hong HUANG, Zhi-ying ZHU

期刊论文

Development of dimensionless P-I diagram for curved SCS sandwich shell subjected to uniformly distributed blast pressure

Yonghui WANG, Ximei ZHAI

期刊论文

Analysis of synergy degree and its influencing factors in hydropower EPC project management

Jiwei ZHU, Hua GAO, Jiangrui WANG

期刊论文

An assessment of surrogate fuel using Bayesian multiple kernel learning model in sight of sooting tendency

期刊论文

二自由度精确解耦离散复矢量永磁同步电机电流控制器

Meng WANG, Jia-qiang YANG, Xiang ZHANG, Chang-sheng ZHU

期刊论文

Iterative finite element model of nonlinear viscoplastic analyses for blended granular porous media

WU Yuching, ZHU Cimian

期刊论文

六自由度光栅干涉仪中的无偏溯源角表达法

常笛1,2,胡鹏程1,2,谭久彬1,2

期刊论文

论正态云模型的普适性

李德毅,刘常昱

期刊论文