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Probabilistic stability of uncertain composite plates and stochastic irregularity in their buckling modeshapes: A semi-analytical non-intrusive approach

《结构与土木工程前沿（英文）》   页码 179-190 doi: 10.1007/s11709-022-0888-z

摘要： In this study, the mechanical properties of the composite plate were considered Gaussian random fields and their effects on the buckling load and corresponding mode shapes were studied by developing a semi-analytical non-intrusive approach. The random fields were decomposed by the Karhunen−Loève method. The strains were defined based on the assumptions of the first-order and higher-order shear-deformation theories. Stochastic equations of motion were extracted using Euler–Lagrange equations. The probabilistic response space was obtained by employing the non-intrusive polynomial chaos method. Finally, the effect of spatially varying stochastic properties on the critical load of the plate and the irregularity of buckling mode shapes and their sequences were studied for the first time. Our findings showed that different shear deformation plate theories could significantly influence the reliability of thicker plates under compressive loading. It is suggested that a linear relationship exists between the mechanical properties’ variation coefficient and critical loads’ variation coefficient. Also, in modeling the plate properties as random fields, a significant stochastic irregularity is obtained in buckling mode shapes, which is crucial in practical applications.

关键词： uncertain composite plate     stochastic assume mode method     Karhunen−Loève theorem     polynomial chaos approach     plate buckling     irregularity in buckling mode shapes    

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A novel structural modification to eliminate the early coupling between bending and torsional mode shapes

Nazim Abdul NARIMAN

《结构与土木工程前沿（英文）》 2017年 第11卷 第2期   页码 131-142 doi: 10.1007/s11709-016-0376-4

摘要： In this paper, a novel structural modification approach has been adopted to eliminate the early coupling between the bending and torsional mode shapes of vibrations for a cable stayed bridge model generated using ABAQUS software. Two lateral steel beams are added to the middle span of the structure. Frequency analysis is dedicated to obtain the natural frequencies of the first eight mode shapes of vibrations before and after the structural modification approach. Numerical simulations of wind excitations are conducted for the 3D model of the cable stayed bridge with duration of 30 s supporting on real data of a strong wind from the literature. Both vertical and torsional displacements are calculated at the mid span of the deck to analyze both the bending and the torsional stiffness of the system before and after the structural modification. The results of the frequency analysis after applying lateral steel beams declared a safer structure against vertical and torsional vibrations and rarely expected flutter wind speed. Furthermore, the coupling between the vertical and torsional mode shapes has been removed to larger natural frequencies magnitudes with a high factor of safety. The novel structural approach manifested great efficiency in increasing vertical and torsional stiffness of the structure.

关键词： aeroelastic instability     structural damping     flutter wind speed     bending stiffness     torsional stiffness    

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A new meshless approach for bending analysis of thin plates with arbitrary shapes and boundary conditions

《结构与土木工程前沿（英文）》 2022年 第16卷 第1期   页码 75-85 doi: 10.1007/s11709-021-0798-5

摘要： An efficient and meshfree approach is proposed for the bending analysis of thin plates. The approach is based on the choice of a set of interior points, for each of which a basis function can be defined. Plate deflection is then approximated as the linear combination of those basis functions. Unlike traditional meshless methods, present basis functions are defined in the whole domain and satisfy the governing differential equation for plate. Therefore, no domain integration is needed, while the unknown coefficients of deflection expression could be determined through boundary conditions by using a collocation point method. Both efficiency and accuracy of the approach are shown through numerical results of plates with arbitrary shapes and boundary conditions under various loads.

关键词： plate     bending     meshless method     collocation    

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A comprehensive review of greenhouse shapes and its applications

Ravinder Kumar SAHDEV,Ashwani Kumar DHINGRA,Mahesh KUMAR

《能源前沿（英文）》 2019年 第13卷 第3期   页码 427-438 doi: 10.1007/s11708-017-0464-8

摘要： Greenhouse technology is a practical option for the production and drying of agricultural products in controlled environment. For the successful design of a greenhouse, the selection of a suitable shape and orientation is of great importance. Of various shapes of greenhouses, the even-span roof and the Quonset shape greenhouses are the most commonly used for crop cultivation and drying. The orientation of greenhouses is kept east–west for maximum utilization of solar radiations. Hybrid and modified greenhouse dryers have been proposed for drying of products. The agricultural products dried in greenhouses are found to be better in quality as compared to open sun drying because they are protected from dust, rain, insects, birds and animals. Moreover, various greenhouses shapes along with their applications have been reviewed.

关键词： greenhouse shapes     drying     solar energy     agriculture products     orientation    

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Catalyst particle shapes and pore structure engineering for hydrodesulfurization and hydrodenitrogenation

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 897-908 doi: 10.1007/s11705-021-2127-x

摘要： Catalyst particle shapes and pore structure engineering are crucial for alleviating internal diffusion limitations in the hydrodesulfurization (HDS)/hydrodenitrogenation (HDN) of gas oil. The effects of catalyst particle shapes (sphere, cylinder, trilobe, and tetralobe) and pore structures (pore diameter and porosity) on HDS/HDN performance at the particle scale are investigated via mathematical modeling. The relationship between particle shape and effectiveness factor is first established, and the specific surface areas of different catalyst particles show a positive correlation with the average HDS/HDN reaction rates. The catalyst particle shapes primarily alter the average HDS/HDN reaction rate to adjust the HDS/HDN effectiveness factor. An optimal average HDS/HDN reaction rate exists as the catalyst pore diameter and porosity increase, and this optimum value indicates a tradeoff between diffusion and reaction. In contrast to catalyst particle shapes, the catalyst pore diameter and the porosity of catalyst particles primarily alter the surface HDS/HDN reaction rate to adjust the HDS/HDN effectiveness factor. This study provides insights into the engineering of catalyst particle shapes and pore structures for improving HDS/HDN catalyst particle efficiency.

关键词： hydrodesulfurization     hydrodenitrogenation     particle shape     pore structure    

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An ANN-exhaustive-listing method for optimization of multiple building shapes and envelope properties

Yaolin LIN, Wei YANG

《能源前沿（英文）》 2021年 第15卷 第2期   页码 550-563 doi: 10.1007/s11708-019-0607-1

摘要： With increasing awareness of sustainability, demands on optimized design of building shapes with a view to maximize its thermal performance have become stronger. Current research focuses more on building envelopes than shapes, and thermal comfort of building occupants has not been considered in maximizing thermal performance in building shape optimization. This paper attempts to develop an innovative ANN (artificial neural network)-exhaustive-listing method to optimize the building shapes and envelope physical properties in achieving maximum thermal performance as measured by both thermal load and comfort hour. After verified, the developed method is applied to four different building shapes in five different climate zones in China. It is found that the building shape needs to be treated separately to achieve sufficient accuracy of prediction of thermal performance and that the ANN is an accurate technique to develop models of discomfort hour with errors of less than 1.5%. It is also found that the optimal solutions favor the smallest window-to-external surface area with triple-layer low-E windows and insulation thickness of greater than 90 mm. The merit of the developed method is that it can rapidly reach the optimal solutions for most types of building shapes with more than two objective functions and large number of design variables.

关键词： ANN (artificial neural network)     exhaustive-listing     building shape     optimization     thermal load     thermal comfort    

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Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

《结构与土木工程前沿（英文）》 2019年 第13卷 第3期   页码 542-556 doi: 10.1007/s11709-018-0496-0

摘要： The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve, leading to quick-prediction of the parameters of single circular void. In this work, mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed. A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the problem. In each iteration starting from each initial guess, the difference between the computationally obtained impedance curve and the target impedance curve has been reduced. This methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam. A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length, but not the precise location along beam-width.

关键词： piezoelectricity     impedance curve     mode shapes     inverse problem     flaw detection     curve shifting    

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Robust SVM-direct torque control of induction motor based on sliding mode controller and sliding mode

Abdelkarim AMMAR,Amor BOUREK,Abdelhamid BENAKCHA

《能源前沿（英文）》 2020年 第14卷 第4期   页码 836-849 doi: 10.1007/s11708-017-0444-z

摘要： This paper proposes a design of control and estimation strategy for induction motor based on the variable structure approach. It describes a coupling of sliding mode direct torque control (DTC) with sliding mode flux and speed observer. This algorithm uses direct torque control basics and the sliding mode approach. A robust electromagnetic torque and flux controllers are designed to overcome the conventional SVM-DTC drawbacks and to ensure fast response and full reference tracking with desired dynamic behavior and low ripple level. The sliding mode controller is used to generate reference voltages in stationary frame and give them to the controlled motor after modulation by a space vector modulation (SVM) inverter. The second aim of this paper is to design a sliding mode speed/flux observer which can improve the control performances by using a sensorless algorithm to get an accurate estimation, and consequently, increase the reliability of the system and decrease the cost of using sensors. The effectiveness of the whole composed control algorithm is investigated in different robustness tests with simulation using Matlab/Simulink and verified by real time experimental implementation based on dS pace 1104 board.

关键词： induction motor     direct torque control (DTC)     space vector modulation (SVM)     sliding mode control (SMC)     sliding mode observer (SMO)     dS1104    

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基于双重分组和密钥计数的并行认证模式

黄玉划,胡爱群,宋宇波

《中国工程科学》 2004年 第6卷 第7期   页码 70-74

摘要：

由于CBC－MAC模式不可并行处理，提出了一种基于双重分组的并行认证模式(PKCB)。PKCB模式同并行认证模式PMAC相比，安全性和速率都有显著提高，PKCB认证模式与CTR（计数器）加密模式结合可构成分组密码算法的一种全工作模式。在此基础上提出了一种基于密钥计数的并行认证模式（KCTR－MAC）。KCTR－MAC模式安全性比PMAC模式高得多，而速率未降低，KCTR－MAC认证模式和CTR加密模式结合也可构成分组密码算法的一种全工作模式（2CTR），2CTR模式的综合性能不亚于标准模式CCM（CTR with CBC－MAC），是一种安全快速的实用模式。

关键词： 认证模式     CBC－MAC模式     PMAC模式     CTR模式     CCM模式    

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Experimental investigation of evolutive mode-I and mode-II fracture behavior of fiber-reinforced cemented

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 256-270 doi: 10.1007/s11709-022-0924-z

摘要： The curing temperature-dependent cement hydration causes the nonlinear evolution of fracture behavior and properties of fiber-reinforced cemented paste backfill (CPB) and thus influences the stability of mine backfill materials in deep mines. Therefore, the coupled effect of curing temperature (20, 35, and 45 °C) and cement hydration at different curing times (3, 7, and 28 d) on the mode-I and mode-II fracture behavior and properties of fiber-reinforced CPB is investigated. A comprehensive experimental testing program consisting of semicircular bend tests, direct shear tests, measurement of volumetric water content and matric suction, TG/DTG tests, and SEM observation is carried out. The results show that the coupled thermochemical effect results in strongly nonlinear development of pre- and post-peak behavior of fiber-reinforced CPB. Moreover, the results discover a positive linear correlation between fracture toughness and shear strength parameters and also reveal the vital role played by matric suction in the formation of fracture toughness. Furthermore, predictive functions are developed to estimate the coupled thermochemical effect on the development of KIc and KIIc. Therefore, the findings and the developed mathematical tools have the potential to promote the successful application of fiber-reinforced CPB technology in deep underground mines.

关键词： fiber reinforcement     cemented paste backfill     fracture behavior     underground mine     cement hydration    

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复杂形状的扩展目标联合跟踪与分类 Research Articles

王丽萍,占荣辉,黄源,张军,庄钊文

《信息与电子工程前沿（英文）》 2021年 第22卷 第6期   页码 839-861 doi: 10.1631/FITEE.2000061

摘要： 本文解决具有复杂形状的单扩展目标联合跟踪与分类（joint tracking and classification, JTC）问题。为描述复杂形状，首先利用随机超曲面模型（random hypersurface model, RHM）将空间扩展状态建模为星凸形状，并将其作为目标分类的特征信息。利用两个向量对目标状态建模，以减轻高维状态空间和严重非线性观测模型对目标状态估计的影响，并利用归一化傅立叶描述子的欧氏距离度量获得类别概率更新的解析解。因此，该方法被称为“JTC-RHM方法”。此外，为解决检测不确定和杂波情况下的单扩展目标JTC问题，将所提JTC-RHM方法整合到Bernoulli滤波框架中，提出JTC-RHM-Ber滤波算法。特别地，推导了该滤波算法的递推表达式。仿真结果表明：（1）与基于随机矩阵模型的JTC算法相比，所提JTC-RHM方法能更准确地对不同形状、相似大小的目标进行分类；（2）与基于星凸RHM的扩展目标跟踪算法相比，所提算法对目标状态性能估计更优；（3）所提JTC-RHM-Ber滤波算法在状态检测和估计方面具有良好性能，能够正确地实现目标分类。

关键词： 扩展目标；傅里叶描述子；联合跟踪与分类；随机超曲面模型；伯努利滤波器    

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An adaptive sliding mode control technology for weld seam tracking

Jie LIU,Youmin HU,Bo WU,Kaibo ZHOU,Mingfeng GE

《机械工程前沿（英文）》 2015年 第10卷 第1期   页码 95-101 doi: 10.1007/s11465-015-0332-3

摘要：

A novel adaptive sliding mode control algorithm is derived to deal with seam tracking control problem of welding robotic manipulator, during the process of large-scale structure component welding. The proposed algorithm does not require the precise dynamic model, and is more practical. Its robustness is verified by the Lyapunov stability theory. The analytical results show that the proposed algorithm enables better high-precision tracking performance with chattering-free than traditional sliding mode control algorithm under various disturbances.

关键词： weld seam tracking     welding robotic manipulator     adaptive control     sliding mode control    

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Relative vibration identification of cutter and workpiece based on improved bidimensional empirical mode

Jiasheng LI, Xingzhan LI, Wei WEI, Pinkuan LIU

《机械工程前沿（英文）》 2020年 第15卷 第2期   页码 227-239 doi: 10.1007/s11465-020-0587-1

摘要： In the process of cutting, the relative vibration between the cutter and the workpiece has an important effect on the surface topography. In this study, the bidimensional empirical mode decomposition (BEMD) method is used to identify such effect. According to Riesz transform theory, a type of isotropic monogenic signal is proposed. The boundary data is extended on the basis of a similarity principle that deals with serious boundary effect problem. The decomposition examples show that the improved BEMD can effectively solve the problem of boundary effect and decompose the original machined surface topography at multiple scales. The characteristic surface topography representing the relative vibration between the cutter and the workpiece through feature identification is selected. In addition, the spatial spectrum analysis of the extracted profile is carried out. The decimal part of the frequency ratio that has an important effect on the shape of the contour can be accurately identified through contour extraction and spatial spectrum analysis. The decomposition results of simulation and experimental surface morphology demonstrate the validity of the improved BEMD algorithm in realizing the relative vibration identification between the cutter and the workpiece.

关键词： bidimensional empirical mode decomposition     spatial spectrum analysis     boundary effect     vibration identification     surface topography    

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Exploration of interconnected factory mode: Haier Jiaozhou Air Conditioner Interconnected Factory

Yunjie ZHOU

《工程管理前沿（英文）》 2017年 第4卷 第4期   页码 500-503 doi: 10.15302/J-FEM-2017105

关键词： interconnected factory mode     user-centered     mass customization     interconnection    

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Gained switching-based fuzzy sliding mode control for a discrete-time underactuated robotic system with

Hui LI, Ruiqin LI, Jianwei ZHANG

《机械工程前沿（英文）》 2021年 第16卷 第2期   页码 353-362 doi: 10.1007/s11465-020-0620-4

摘要： This study proposes a gained switching-based discrete-time sliding mode control method to address the chattering issue in disturbed discrete-time systems, which suffer from various unknown uncertainties. Through the new structure of the designed reaching law, the proposed method can effectively increase the convergence speed while guaranteeing chattering-free control. The performance of controlling underactuated robotic systems can be further improved by the adoption of fuzzy logic to perform adaptive online hyper-parameter tuning. In addition, an underactuated robotic system with uncertainties is studied to validate the effectiveness of the proposed reaching law. Results reveal the dynamic performance and robustness of the proposed reaching law in the studied system and prove the proposed method’s superiority over other state-of-the-art methods.

关键词： sliding-mode control     robot control     discrete-time uncertain systems     fuzzy logic    

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标题 作者 时间 类型 操作

Probabilistic stability of uncertain composite plates and stochastic irregularity in their buckling modeshapes: A semi-analytical non-intrusive approach

期刊论文

A novel structural modification to eliminate the early coupling between bending and torsional mode shapes

Nazim Abdul NARIMAN

期刊论文

A new meshless approach for bending analysis of thin plates with arbitrary shapes and boundary conditions

期刊论文

A comprehensive review of greenhouse shapes and its applications

Ravinder Kumar SAHDEV,Ashwani Kumar DHINGRA,Mahesh KUMAR

期刊论文

Catalyst particle shapes and pore structure engineering for hydrodesulfurization and hydrodenitrogenation

期刊论文

An ANN-exhaustive-listing method for optimization of multiple building shapes and envelope properties

Yaolin LIN, Wei YANG

期刊论文

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

期刊论文

Robust SVM-direct torque control of induction motor based on sliding mode controller and sliding mode

Abdelkarim AMMAR,Amor BOUREK,Abdelhamid BENAKCHA

期刊论文

基于双重分组和密钥计数的并行认证模式

黄玉划,胡爱群,宋宇波

期刊论文

Experimental investigation of evolutive mode-I and mode-II fracture behavior of fiber-reinforced cemented

期刊论文

复杂形状的扩展目标联合跟踪与分类

王丽萍,占荣辉,黄源,张军,庄钊文

期刊论文

An adaptive sliding mode control technology for weld seam tracking

Jie LIU,Youmin HU,Bo WU,Kaibo ZHOU,Mingfeng GE

期刊论文

Relative vibration identification of cutter and workpiece based on improved bidimensional empirical mode

Jiasheng LI, Xingzhan LI, Wei WEI, Pinkuan LIU

期刊论文

Exploration of interconnected factory mode: Haier Jiaozhou Air Conditioner Interconnected Factory

Yunjie ZHOU

期刊论文

Gained switching-based fuzzy sliding mode control for a discrete-time underactuated robotic system with

Hui LI, Ruiqin LI, Jianwei ZHANG

期刊论文