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Geometrical nonlinear deformation model and its experimental study on bimorph giant magnetostrictive

LIU Wei, JIA Zhenyuan, WANG Fuji, ZHANG Yongshun, GUO Dongming

《机械工程前沿(英文)》 2008年 第3卷 第3期   页码 313-317 doi: 10.1007/s11465-008-0048-8

摘要: The geometrical nonlinearity of a giant magnetostrictive thin film (GMF) can be clearly detected under the magnetostriction effect. Thus, using geometrical linear elastic theory to describe the strain, stress, and constitutive relationship of GMF is inaccurate. According to nonlinear elastic theory, a nonlinear deformation model of the bimorph GMF is established based on assumptions that the magnetostriction effect is equivalent to the effect of body force loaded on the GMF. With Taylor series method, the numerical solution is deduced. Experiments on TbDyFe/Polyimide (PI)/SmFe and TbDyFe/Cu/SmFe are then conducted to verify the proposed model, respectively. Results indicate that the nonlinear deflection curve model is in good conformity with the experimental data.

关键词: magnetostrictive     nonlinear     magnetostriction     inaccurate     geometrical nonlinearity    

Implementation of total Lagrangian formulation for the elasto-plastic analysis of plane steel frames exposed to fire

Bing XIA, Yuching WU, Zhanfei HUANG

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 257-266 doi: 10.1007/s11709-012-0163-9

摘要: In this paper, the co-rotational total Lagrangian forms of finite element formulations are derived to perform elasto-plastic analysis for plane steel frames that either experience increasing external loading at ambient temperature or constant external loading at elevated temperatures. Geometric nonlinearities and thermal-expansion effects are considered. A series of programs were developed based on these formulations. To verify the accuracy and efficiency of the nonlinear finite element programs, numerical benchmark tests were performed, and the results from these tests are in a good agreement with the literature. The effects of the nonlinear terms of the stiffness matrices on the computational results were investigated in detail. It was also demonstrated that the influence of geometric nonlinearities on the incremental steps of the finite element analysis for plane steel frames in the presence of fire is limited.

关键词: co-rotational     total Lagrangian     geometrical nonlinearity     fire     elasto-plastic    

Nanopositioning and Nonlinearity Compensation for Step Imprint Lithography Tool

LU Bing-heng, LIU Hong-zhong, DING Yu-cheng, WANG Li, QIU Zhi-hui

《机械工程前沿(英文)》 2006年 第1卷 第1期   页码 6-13 doi: 10.1007/s11465-005-0003-x

摘要:

In this paper, the motion mode and nanopositioning accuracy in the step imprinting lithography process are presented, and the positioning errors different from the traditional errors, such as the gap error existing in the hinges of the stage structure and the random error produced during the process of the stage position adjustment, are analyzed. To avoid and eliminate these nonlinearity errors, radial basis function proportional integral derivative and position control algorithms are introduced into the macroand microdriving processes, respectively. The innovation of this driving method is that the motion locus is monotone, nonoscillatory, and a multistep approaching target, which eliminates the root of the random error by single direction driving mode and avoids the backlash error through preloading function. Driving experiments of different motion ranges prove that this nonlinearity compensation is very effective and the positioning accuracy during the step imprinting process can be improved up to 10 nm.

关键词: different     nonoscillatory     nonlinearity     integral derivative     positioning    

Application and evaluation of optical distance measurements in geometrical quality testing of microgears

Albert ALBERS, Duotai PAN, Leif MARXEN, Claudia BECKE,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 261-269 doi: 10.1007/s11465-010-0100-3

摘要: Microgears are increasingly important in industry. Compared to normal gears, the quality assurance of microgears needs more accurately measured data and simple but feasible measurement methods because of their dimension particula

关键词: microgear     optical distance measurement     profile deviation     CWL sensor     micromechanical technology (MMT)    

The role of geometrical features in the architectural-structural interaction: Some case studies of the

Maryam ZANDIYEHVAKILI, Isa HOJAT, Mehdi MAHMUDI

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 716-724 doi: 10.1007/s11709-018-0508-0

摘要: This research aims to enhance the interaction between a structure and its architectural form. Having a qualitative approach, the present work discovers some successfully used geometrical features of the Iranian ancient architecture in terms of the architectural-structural interaction. We define four qualitative criteria for this assessment, i.e., construction-ability, cost effectiveness, participation of the structure in fulfillment of the visual, and functional-semantic needs of the architectural form. For this purpose, two case studies including the Jamé Mosque of Isfahan and the Soltaniyeh building are investigated. The outcomes of this research help designers to not only design efficient structures by adapting non-load bearing elements with the general form of the structure, but also meet concepts such as the unity or perfectionism in the structure.

关键词: architectural-structural interaction     geometrical features     structure     architectural form     Iranian ancient architecture    

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

Contact of surfaces and contact characteristics of offset surfaces

CAO Lixin, GONG Hu, LIU Jian

《机械工程前沿(英文)》 2008年 第3卷 第3期   页码 318-324 doi: 10.1007/s11465-008-0067-5

摘要: Based on differential geometry, the contact problems of two surfaces are discussed in this paper. The relationship between the contact status of two surfaces and that of offset surfaces are also analyzed. For a 5-axis NC machining, some research such as optimization of cutter location and calculation of the geometrical cusp height are important. The research results indicate that the relative normal curvature is an important geometrical invariant for describing the contact state of two surfaces. For point contact two surfaces, the calculation equation for the second order remained error is given. For line contact two surfaces, the condition of the second order line contact is that the principal directions and curvatures of the two surfaces are the same along the contact curve. If two surfaces keep the second order line contact, their two offset surfaces will also keep the second order line contact, and their third order remained errors are also uniform with that of the two offset surfaces.

关键词: relative     important geometrical     relationship     geometrical invariant     calculation    

Contribution of black carbon to nonlinearity of sorption and desorption of acetochlor on sediment

Jianqiu LIU, Yaobin ZHANG, Hong CHEN, Yazhi ZHAO, Xie QUAN

《环境科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 69-74 doi: 10.1007/s11783-008-0076-y

摘要: In order to investigate the contribution of various black carbon (BC) contents to nonlinearity of sorption and desorption isotherms for acetochlor on sediment, equilibrium sorption and desorption isotherms were determined to measure sorption and desorption of acetochlor in sediment amended with various amounts of BC. In this paper, two types of BC referred to as BC400 and BC500 were prepared at 400°C and 500°C, respectively. Higher preparation temperature facilitated the formation of micropores on BC to enhance its sorption capacity. Increase of the BC content obviously increased the sorption amount and reduced the desorption amount for acetochlor. When the BC500 contents in total organic carbon (TOC) increased from 0 to 60%, Freundlich sorption coefficient ( ) increased from 4.07 to 35.74, and desorption hysteresis became gradually obvious. When the content of BC in TOC was lower than 23%, the sorption isotherm had a significant linear correlation ( = 0.05). In case of desorption, a significant nonlinear change could be observed when the content of BC was up to 13%. Increase of BC content in the sediment would result in shifting the sorption-desorption isotherms from linearity to nonlinearity, which indicated that contribution of BC to nonlinear adsorption fraction became gradually remarkable.

关键词: black carbon (BC)     sorption     desorption     sediment    

Analysis of suitable geometrical parameters for designing a tendon-driven under-actuated mechanical finger

Francesco PENTA,Cesare ROSSI,Sergio SAVINO

《机械工程前沿(英文)》 2016年 第11卷 第2期   页码 184-194 doi: 10.1007/s11465-016-0385-y

摘要:

This study aims to optimize the geometrical parameters of an under-actuated mechanical finger by conducting a theoretical analysis of these parameters. The finger is actuated by a flexion tendon and an extension tendon. The considered parameters are the tendon guide positions with respect to the hinges. By applying such an optimization, the correct kinematical and dynamical behavior of the closing cycle of the finger can be obtained. The results of this study are useful for avoiding the snap-through and the single joint hyperflexion, which are the two breakdowns most frequently observed during experimentation on prototypes. Diagrams are established to identify the optimum values for the tendon guides position of a finger with specified dimensions. The findings of this study can serve as guide for future finger design.

关键词: tendon-driven fingers     mechanical finger design     under-actuated mechanical systems    

Finite element analysis of creep for plane steel frames in fire

Hui ZHU, Yuching WU

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 297-307 doi: 10.1007/s11709-012-0162-x

摘要: Steel is widely used for the construction of bridges, buildings, towers, and other structures because of its great strength, light weight, ductility, and ease of fabrication, but the cost of fireproofing is a major disadvantage. Therefore, the resistance of a steel structure to fire is a significant subject for modern society. In the past, for simplification, creep behavior was not taken into account in research on the resistance of a steel structure to fire. However, it was demonstrated that the effect of creep is considerable at temperatures that commonly reach 600°C and should not be neglected in this context. In this paper, a co-rotational total Lagrangian finite element formulation is derived, and the corresponding numerical model is developed to study the creep behavior of plane steel frames in fire conditions. The geometric nonlinearity, material nonlinearity, high temperature creep, and temperature rate of change are taken into account. To verify the accuracy and efficiency of the numerical model, four prototypical numerical examples are analyzed using this model, and the results show very good agreement with the solutions in the literature. Next, the numerical model is used to analyze the creep behavior of the plane steel frames under decreasing temperatures. The results indicate that the effect of creep is negligible at temperatures lower than 500°C and is considerable at temperatures higher than 500°C. In addition, the heating rate is a critical factor in the failure point of the steel frames. Furthermore, it is demonstrated that the deflection at the midpoint of the steel beam, considering creep behavior, is approximately 13% larger than for the situation in which creep is ignored. At temperatures higher than 500°C, the deformed steel member may recover approximately 20% of the total deflection. The application of the numerical model proposed in this paper is greatly beneficial to the steel industry for creep analysis, and the numerical results make a significant contribution to the understanding of resistance and protection for steel structures against disastrous fires.

关键词: creep     plane steel frame     fire     finite element method     geometric nonlinearity    

Optimal dome design considering member-related design constraints

Tugrul TALASLIOGLU

《结构与土木工程前沿(英文)》 2019年 第13卷 第5期   页码 1150-1170 doi: 10.1007/s11709-019-0543-5

摘要: This study proposes to optimize the design of geometrically nonlinear dome structures. A new Multi-objective Optimization Algorithm named Pareto Archived Genetic Algorithm (PAGA), which has an ability of integrating the nonlinear structural analysis with the provisions of American Petroleum Institute specification is employed to optimize the design of ellipse and sphere-shaped dome configurations. Thus, it is possible to investigate how the qualities of optimal designations vary considering the shape, size, and topology-related design variables. Furthermore, the computing efficiency of PAGA is evaluated considering six multi-objective optimization algorithms and eight quality measuring indicators. It is shown that PAGA has a capability of both exploring an increased number of pareto solutions and predicting a pareto front with a higher convergence degree. Moreover, the inclusion of shape-related design variables leads to a decrease in both the weights of dome structures and their load-carrying capacities. However, the designer easily determines the most requested optimal design through the archiving feature of PAGA. Thus, it is also demonstrated that the proposed optimal design procedure increases the correctness degree in the evaluation of optimal dome designs through the tradeoff analysis. Consequently, PAGA is recommended as an optimization tool for the design optimization of geometrically nonlinear dome structures.

关键词: dome structure     geometric nonlinearity     multi-objective optimization     API RP2A-LRFD    

Shape optimization of aluminium alloy spherical reticulated shells considering nonlinearities

Wei LIU; Lishu XU; Shaojun ZHU; Lijuan LI; Feng LIU; Zhe XIONG

《结构与土木工程前沿(英文)》 2022年 第16卷 第12期   页码 1565-1580 doi: 10.1007/s11709-022-0867-4

摘要: This study proposes a shape optimization method for K6 aluminum alloy spherical reticulated shells with gusset joints, considering geometric, material, and joint stiffness nonlinearities. The optimization procedure adopts a genetic algorithm in which the elastoplastic non-linear buckling load is selected as the objective function to be maximized. By confinement of the adjustment range of the controlling points, optimization results have enabled a path toward achieving a larger elastoplastic non-linear buckling load without changing the macroscopic shape of the structure. A numerical example is provided to demonstrate the effectiveness of the proposed method. In addition, the variation in structural performance during optimization is illustrated. Through parametric analysis, practical design tables containing the parameters of the optimized shape are obtained for aluminum alloy spherical shells with common geometric parameters. To explore the effect of material nonlinearity, the optimal shapes obtained based on considering and not considering material non-linear objective functions, the elastoplastic and elastic non-linear buckling loads, are compared.

关键词: shape optimization     aluminum alloy     spherical reticulated shell     non-linear buckling     material nonlinearity     genetic algorithm    

Experimental and numerical study on microcrack detection using contact nonlinear acoustics

Xiaojia CHEN, Yuanlin WANG

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 137-141 doi: 10.1007/s11709-009-0028-z

摘要: This paper introduces a non-classical nonlinear acoustic theory for microcrack detection in materials, comparing contact nonlinearity with material nonlinearity. The paper’s main work concentrates on the experimental and numerical verification of the effectivity of contact nonlinear acoustic detection by using the contact nonlinear parameter , which can be represented by the ratio of the second-harmonic amplitude to the square of the first-harmonic amplitude. Both experiments and numerical tests are performed. The results show that is sensitive to the initiation of microcracks and varies with the development of the microcracks. The numerical test illustrates the decline of when microcracks penetrate each other.

关键词: microcrack detection     contact nonlinearity     numerical analysis    

A brief review on nonlinear modeling methods and applications of compliant mechanisms

Guangbo HAO,Jingjun YU,Haiyang LI

《机械工程前沿(英文)》 2016年 第11卷 第2期   页码 119-128 doi: 10.1007/s11465-016-0387-9

摘要:

Compliant mechanisms (CMs) have become one of the most popular research themes in mechanisms and robotics because of their merits. This paper aims to provide a brief systematic review on the advances of nonlinear static modeling approaches and the applications of CMs to promote interdisciplinary/multidisciplinary development for associated theories and other new applications. It also predicts likely future directions of applications and theory development.

关键词: compliant mechanisms     modelling     nonlinearity     applications     review    

Kinematical synthesis of an inversion of the double linked fourbar for morphing wing applications

J. AGUIRREBEITIA, R. AVILéS, I. FERNáNDEZ, M. ABASOLO

《机械工程前沿(英文)》 2013年 第8卷 第1期   页码 17-32 doi: 10.1007/s11465-013-0364-5

摘要:

This paper presents the kinematical features of an inversion of the double linked fourbar for morphing wing purposes. The structure of the mechanism is obtained using structural synthesis concepts, from an initial conceptual schematic. Then, kinematic characteristics as instant center of rotation, lock positions, dead point positions and uncertainty positions are derived for this mechanism in order to face the last step, the dimensional synthesis; in this sense, two kinds of dimensional synthesis are arranged to guide the wing along two positions, and to fulfill with the second one some aerodynamic and minimum actuation energy related issues.

关键词: morphing wing     structural synthesis     dimensional synthesis     geometrical kinematics    

标题 作者 时间 类型 操作

Geometrical nonlinear deformation model and its experimental study on bimorph giant magnetostrictive

LIU Wei, JIA Zhenyuan, WANG Fuji, ZHANG Yongshun, GUO Dongming

期刊论文

Implementation of total Lagrangian formulation for the elasto-plastic analysis of plane steel frames exposed to fire

Bing XIA, Yuching WU, Zhanfei HUANG

期刊论文

Nanopositioning and Nonlinearity Compensation for Step Imprint Lithography Tool

LU Bing-heng, LIU Hong-zhong, DING Yu-cheng, WANG Li, QIU Zhi-hui

期刊论文

Application and evaluation of optical distance measurements in geometrical quality testing of microgears

Albert ALBERS, Duotai PAN, Leif MARXEN, Claudia BECKE,

期刊论文

The role of geometrical features in the architectural-structural interaction: Some case studies of the

Maryam ZANDIYEHVAKILI, Isa HOJAT, Mehdi MAHMUDI

期刊论文

Enhancing power generation of piezoelectric bimorph device through geometrical optimization

Action NECHIBVUTE,Albert CHAWANDA,Pearson LUHANGA

期刊论文

Contact of surfaces and contact characteristics of offset surfaces

CAO Lixin, GONG Hu, LIU Jian

期刊论文

Contribution of black carbon to nonlinearity of sorption and desorption of acetochlor on sediment

Jianqiu LIU, Yaobin ZHANG, Hong CHEN, Yazhi ZHAO, Xie QUAN

期刊论文

Analysis of suitable geometrical parameters for designing a tendon-driven under-actuated mechanical finger

Francesco PENTA,Cesare ROSSI,Sergio SAVINO

期刊论文

Finite element analysis of creep for plane steel frames in fire

Hui ZHU, Yuching WU

期刊论文

Optimal dome design considering member-related design constraints

Tugrul TALASLIOGLU

期刊论文

Shape optimization of aluminium alloy spherical reticulated shells considering nonlinearities

Wei LIU; Lishu XU; Shaojun ZHU; Lijuan LI; Feng LIU; Zhe XIONG

期刊论文

Experimental and numerical study on microcrack detection using contact nonlinear acoustics

Xiaojia CHEN, Yuanlin WANG

期刊论文

A brief review on nonlinear modeling methods and applications of compliant mechanisms

Guangbo HAO,Jingjun YU,Haiyang LI

期刊论文

Kinematical synthesis of an inversion of the double linked fourbar for morphing wing applications

J. AGUIRREBEITIA, R. AVILéS, I. FERNáNDEZ, M. ABASOLO

期刊论文