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关键词

遗传算法 2

MapReduce；近似作业；时限；任务调度；掉队任务消除 1

三维构造 1

仿真器 1

优化 1

供水泵站 1

光镊；光致旋转；角动量；微纳转子 1

函数逼近能力 1

协议关系 1

各向异性腐蚀 1

同步扰动随机逼近 1

地质曲面 1

均匀流形逼近和投影 1

多源地质数据 1

大型多支承 1

安全性第一准则 1

对象跟踪 1

广义哈密尔顿—雅可比—贝尔曼方程；非线性最优控制；伽辽金逼近（Galerkin approximation）；勒让德多项式（Legendre polynomials） 1

广义近似空间 1

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Modeling of large-deflection links for compliant mechanisms

Zhonglei FENG, Yueqing YU, Wenjing WANG,

《机械工程前沿（英文）》 2010年第5卷第3期页码 294-301 doi: 10.1007/s11465-010-0019-8

摘要： The traditional pseudo-rigid-body model (PRBM) has one degree of freedom (DOF) and performs a good simulation to the tip locus of flexible links for compliant mechanisms on the basis of a parametric approximation method. In this study, a new approach of a two-DOF PRBM is proposed to simulate both the tip locus and tip deflection angle of large-deflection links for compliant mechanisms on the basis of the angular deflection approximation technique. A linear regression for the spring stiffness coefficient of the 2R PRBM using the optimization technique is presented. The advantage of the new model is well illustrated through a numerical comparison between the 1R and the 2R PRBM.

关键词： compliant mechanism pseudo-rigid-body model (PRBM) large-deflection link angular deflection approximation

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Improved prediction of pile bending moment and deflection due to adjacent braced excavation

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0961-2

摘要： Deep excavations in dense urban areas have caused damage to nearby existing structures in numerous past construction cases. Proper assessment is crucial in the initial design stages. This study develops equations to predict the existing pile bending moment and deflection produced by adjacent braced excavations. Influential parameters (i.e., the excavation geometry, diaphragm wall thickness, pile geometry, strength and small-strain stiffness of the soil, and soft clay thickness) were considered and employed in the developed equations. It is practically unfeasible to obtain measurement data; hence, artificial data for the bending moment and deflection of existing piles were produced from well-calibrated numerical analyses of hypothetical cases, using the three-dimensional finite element method. The developed equations were established through a multiple linear regression analysis of the artificial data, using the transformation technique. In addition, the three-dimensional nature of the excavation work was characterized by considering the excavation corner effect, using the plane strain ratio parameter. The estimation results of the developed equations can provide satisfactory pile bending moment and deflection data and are more accurate than those found in previous studies.

关键词： pile responses excavation prediction deflection bending moments

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New nonlinear stiffness actuator with predefined torque‒deflection profile

《机械工程前沿（英文）》 2023年第18卷第1期 doi: 10.1007/s11465-022-0721-3

摘要： A nonlinear stiffness actuator (NSA) could achieve high torque/force resolution in low stiffness range and high bandwidth in high stiffness range, both of which are beneficial for physical interaction between a robot and the environment. Currently, most of NSAs are complex and hardly used for engineering. In this paper, oriented to engineering applications, a new simple NSA was proposed, mainly including leaf springs and especially designed cams, which could perform a predefined relationship between torque and deflection. The new NSA has a compact structure, and it is lightweight, both of which are also beneficial for its practical application. An analytical methodology that maps the predefined relationship between torque and deflection to the profile of the cam was developed. The optimal parameters of the structure were given by analyzing the weight of the NSA and the mechanic characteristic of the leaf spring. Though sliding friction force is inevitable because no rollers were used in the cam-based mechanism, the sliding displacement between the cam and the leaf spring is very small, and consumption of sliding friction force is very low. Simulations of different torque‒deflection profiles were carried out to verify the accuracy and applicability of performing predefined torque‒deflection profiles. Three kinds of prototype experiments, including verification experiment of the predefined torque‒deflection profile, torque tracking experiment, and position tracking experiment under different loads, were conducted. The results prove the accuracy of performing the predefined torque‒deflection profile, the tracking performance, and the interactive performance of the new NSA.

关键词： compliant actuator nonlinear stiffness actuator nonlinear spring predefined torque−deflection profile

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Thermal deflection analysis of the solidified shell in continuous casting of slab

LIU Hongzhao, WANG Zhongmin

《机械工程前沿（英文）》 2007年第2卷第2期页码 175-179 doi: 10.1007/s11465-007-0029-3

摘要： The thermal deformation problem in the continuous casting of a slab subjected to thermal loading because of the temperature gradient along the solidified shell thickness is investigated. On the basis of the reciprocal theorem of work or Betti-Maxwell s reciprocal theorem and the superposition principle, the deflection expressions for a rectangular plate with the two opposite edges simply supported, and the other two opposite edges clamped under the action of the uniformly distributed load and nonuniform temperature field are derived respectively. The meaning of each term in the deflection expression obtained by the reciprocal theorem of work is explained. Then the practical example is given to calculate the thermal deformation and the bulging deformation of the solidified shell under three tension speeds. This research is useful for analyzing the bulging deformation in the continuous casting of a slab under the static pressure of the molten steel and the thermal loading because of the temperature gradient along the solidified shell thickness.

关键词： s reciprocal loading deflection expression reciprocal opposite

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Instantaneous deflection of light-weight concrete slabs

Behnam VAKHSHOURI, Shami NEJADI

《结构与土木工程前沿（英文）》 2017年第11卷第4期页码 412-423 doi: 10.1007/s11709-017-0416-8

摘要： Construction loading before the age of 28 d can have the most significant effects on the slabs, especially for multi-story structures. The changing properties of the young concrete complicate the prediction of serviceability design requirements also. An experimental investigation is performed on four simply supported Light-Weight Concrete (LWC) one-way slabs subjected to immediate loading at 14 d. Effects of aggregate type, loading levels and cracking moment together with the influences of ultimate moment capacity and service moment on the instantaneous deflection of slabs are studied. Comparison of the obtained results with predictions of existing models in the literature shows considerable differences between the recorded and estimated instantaneous deflection of LWC slabs. Based on sensitivity analysis of the effective parameters, a new equation is proposed and verified to predict the instantaneous deflection of LWC slabs subjected to loading at the age of 14 d.

关键词： instantaneous deflection light-weight concrete expanded polystyrene effective moment of inertia cracking moment moment capacity service moment

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A case study on sample average approximation method for stochastic supply chain network design problem

Yuan WANG, Ruyan SHOU, Loo Hay LEE, Ek Peng CHEW

《工程管理前沿（英文）》 2017年第4卷第3期页码 338-347 doi: 10.15302/J-FEM-2017032

摘要： This study aims to solve a typical long-term strategic decision problem on supply chain network design with consideration to uncertain demands. Existing methods for these problems are either deterministic or limited in scale. We analyze the impact of uncertainty on demand based on actual large data from industrial companies. Deterministic equivalent model with nonanticipativity constraints, branch-and-fix coordination, sample average approximation (SAA) with Bayesian bootstrap, and Latin hypercube sampling were adopted to analyze stochastic demands. A computational study of supply chain network with front-ends in Europe and back-ends in Asia is presented to highlight the importance of stochastic factors in these problems and the efficiency of our proposed solution approach.

关键词： supply chain network stochastic demand sampling average approximation Bayesian bootstrap Latin hypercube sampling

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大型多支承回转窑托轮偏斜接触有限元分析

李学军,张美阳,褚福磊

《中国工程科学》 2007年第9卷第12期页码 16-20

摘要：

针对回转窑托轮偏斜对接触区应力分布的影响，运用赫兹接触理论，推导出托轮与滚圈最大接触应力比与托轮偏斜角的关系；采用有限元方法计算某支承结构托轮平行与呈最大偏斜角时的接触问题，得到支承部件接触应力和等效应力应变分布情况，并得出滚圈和托轮的危险易损部位；为回转窑的轴向调控提供了有效的理论依据。

关键词：大型多支承托轮偏斜接触应力有限元

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analysis of thin-walled box continuous girder with variable cross-sections in considering effect of large deflection

Yuji CHEN, Qizhi LUO,

《结构与土木工程前沿（英文）》 2009年第3卷第4期页码 352-356 doi: 10.1007/s11709-009-0057-7

摘要： In order to study the mechanics behavior of a thin-walled box continuous girder with variable cross-sections, using potential variation theories, considering the effect of shear lag of flange’s stress and the nonlinear geometry of vertical displacement, and evolving five generalized displacements with the spline function, the large deflection problem of the thin-walled box continuous girder with variable cross-section was transformed to a nonlinear algebraic equation, which was solved using the Newton-Raphon iterative method. The results of the calculation show that different shear lag warp functions to the cantilever, top and bottom plate should be taken to analyze the mechanics behavior of the thin-walled box continuous girder reliably. The thin-walled box continuous girder with variable cross-sections has more reasonable stress state and is more adaptable for the longitudinal change of internal forces than that with equal cross-sections. The effect of large deflection on the stress and displacement of the thin-walled box continuous girder with variable cross-sections depends on the values of the load.

关键词： thin-walled box girder with variable cross-sections potential variational theory shear lag large deflection problem

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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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Shape reconstruction of parallelogram flaw

ZHENG Gangfeng, WU Bin, HE Cunfu

《机械工程前沿（英文）》 2008年第3卷第1期页码 17-22 doi: 10.1007/s11465-008-0015-4

摘要： To reconstruct the shape of the scatterer in elastic media, the authors deduce the Born approximation solution of the two-dimensional scattering problem, which includes the shape factor that embodies all information about the shape of the scatterer. Accordingly, the change in the shape of the scatterer only necessitates the number of the corresponding new shape factors. For a parallelogram void in a long Al rod, its shape factor can be obtained. In view of the definition of a characteristic function, the shape factor has a corresponding integral representation. Obviously, the shape factor can be considered as a Fourier transform of the characteristic function, which is reconstructed from the inverse Fourier transform. The integral equation is considered as the basic equation to reconstruct the shape of the scatterer. The identification of the geometrical character of a flaw is then given by the two dimensional inverse Born approximation in a low-frequency range. For the parallelogram void, a theoretical calculating identification is performed. At the same time, the numerical results are obtained by the finite element method.

关键词： approximation scatterer scattering problem information inverse

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广义近似空间与粗糙分类代数

刘永红

《中国工程科学》 2006年第8卷第3期页码 39-48

摘要：

提出了广义近似空间、粗近似公理、干扰集公理、粗糙集的分类原则、粗选原则、不确定偶集原则、精选原则、对策分类、量子逻辑分类、bit量子对称分类、不可比集、bit空间集、协议关系、粗糙集函数、粗糙分类代数和粗糙单代数等基本概念，并提出了一个猜想；展示了一些新观点；基于协议关系构造了粗糙商代数和粗糙子代数，给出了回避-归并算法及算例。

关键词：广义近似空间粗糙集粗糙分类代数协议关系粗糙单代数粗糙商代数粗糙子代数

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连续非线性最优控制问题的勒让德—伽辽金逼近方法 Article

Xue-song CHEN

《信息与电子工程前沿（英文）》 2017年第18卷第10期页码 1479-1487 doi: 10.1631/FITEE.1601101

摘要：该方法基于伽辽金逼近理论（Galerkin approximation）求解广义哈密尔顿—雅可比—贝尔曼（Hamilton-Jacobi-Bellman, GHJB）方程。

关键词：广义哈密尔顿—雅可比—贝尔曼方程；非线性最优控制；伽辽金逼近（Galerkin approximation）；勒让德多项式（Legendre polynomials）

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粘贴玻璃钢加固混凝土组合梁挠度研究

段敬民,钱永久,曾宪桃

《中国工程科学》 2004年第6卷第10期页码 79-82

摘要：

将一定几何尺寸的玻璃钢板粘贴在混凝土梁的受拉区，能有效地提高混凝土梁的抗弯承载能力和混凝土梁的横向刚度。通过解析的方法，分别考虑组合梁在3种不同受力状态下，对玻璃钢板中拉力进行解析，得到了组合梁在不同载荷作用下的挠度表达式。

关键词：粘贴加固玻璃钢混凝土组合梁挠度

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满足MapReduce环境下近似处理的时限要求 Article

Ming-hao HU, Chang-jian WANG, Yu-xing PENG

《信息与电子工程前沿（英文）》 2017年第18卷第11期页码 1754-1772 doi: 10.1631/FITEE.1601056

摘要：为了向大数据分析提供实时结果，在现今的生产环境中满足MapReduce作业的时限要求是非常关键的。许多研究致力于解决时限要求的问题，目前存在两种代表性的方法。第一种是分配适量资源以在时限前完成整个作业，在时限紧迫或资源受限时，该方法会错过时限；另一种是在时限约束下运行预数据量的样本，该方法能满足时限但无法使数据量最大化。在本文中，我们提出一个时限–导向的任务调度方法来解决上述问题，称为“Dart”。给定具体的时限和可用资源量时，Dart使用基于历史数据和作业运行状态的迭代估计法准确预测作业完成时间。基于时间预测，Dart法采用接近–修改算法做出动态调度决策，在满足时限的情况下将可处理数据量最大化并消除掉队任务。同时Dart法可有效地避免任务失败和数据倾斜，防止其性能受影响。在包含64个虚拟机的集群上使用OpenCloud和Facebook的工作负载对Dart法进行评估。结果表明Dart法在时限紧迫和资源受限情况下能有效满足时限并将处理数据量最大化。

关键词： MapReduce；近似作业；时限；任务调度；掉队任务消除

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工程饱和介质中漩涡光的调制不稳定性 Review

D.G. Pires, N.M. Litchinitser

《工程（英文）》 2022年第17卷第10期页码 31-43 doi: 10.1016/j.eng.2022.04.022

摘要：

光束在水下环境、雾、云或生物组织等混浊介质中的传播在科学和技术中有着越来越重要的应用，包括生物成像、水下和自由空间通信技术。虽然这些应用在传统上依赖于常规的线性偏振高斯光束，但光具有许多未被发掘的自由度，如自旋角动量（SAM）和轨道角动量（OAM）。本文提出了具有“旋转”自由度的复杂光束在工程化非线性胶体介质中的非线性光-物质相互作用。利用变分法和摄动法，我们考虑了非圆柱光学涡旋、椭圆光学涡旋和高阶贝塞尔光束在时间上的积分（HOBBIT），来预测这些光束演化的动力学行为和稳定性。这些结果可应用于许多强散射环境下涉及光透射的情况。

关键词： Optical vortex Orbital angular momentum Modulation instability Turbid media