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Goryachkin’s agricultural mechanics

Vera CHINENOVA

《机械工程前沿(英文)》 2016年 第11卷 第1期   页码 87-94 doi: 10.1007/s11465-016-0378-x

摘要:

The paper contributes to the development of applied mechanics by establishing a new discipline, namely, agricultural mechanics by academician Vasilii Prohorovich Goryachkin (1868–1935) who was an apprentice of Nikolay Yegorovich Zhukovsky and a graduate of the Moscow University (current known as Moscow State University) and the Imperial Higher Technical School.

关键词: theory of mechanisms and machines     agricultural machinery engineering     agricultural mechanics    

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 623-642 doi: 10.1007/s11709-021-0726-8

摘要: In this study, gradual and sudden reduction methods were combined to simulate a progressive failure in notched composite plates using a macro mechanics approach. Using the presented method, a progressive failure is simulated based on a linear softening law prior to a catastrophic failure, and thereafter, sudden reduction methods are employed for modeling a progressive failure. This combination method significantly reduces the computational cost and is also capable of simultaneously predicting the first and last ply failures (LPFs) in composite plates. The proposed method is intended to predict the first ply failure (FPF), LPF, and dominant failure modes of carbon/epoxy and glass/epoxy notched composite plates. In addition, the effects of mechanical properties and different stacking sequences on the propagation of damage in notched composite plates were studied. The results of the presented method were compared with experimental data previously reported in the literature. By comparing the numerical and experimental data, it is revealed that the proposed method can accurately simulate the failure propagation in notched composite plates at a low computational cost.

关键词: progressive failure     notched composite plate     Hashin failure criterion     macro mechanics approach     finite element method    

航空航天技术与力学

陈士橹

《中国工程科学》 2003年 第5卷 第3期   页码 25-26

摘要:

文章论述了航空航天技术发展与力学学科发展的依存关系,讨论了力学学科间的交叉及交叉学科的产生,重点介绍了飞行力学与空气动力学、结构力学、一般力学、自动控制等学科间的关系,进而讨论了飞行力学的分支——弹性飞行器动力学。

关键词: 空气动力学     结构力学     一般力学     自动控制     飞行力学     弹性飞行器动力学    

Creep life assessment of aero-engine recuperator based on continuum damage mechanics approach

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0702-6

摘要: The creep life of an aeroengine recuperator is investigated in terms of continuum damage mechanics by using finite element simulations. The effects of the manifold wall thickness and creep properties of brazing filler metal on the operating life of the recuperator are analyzed. Results show that the crack initiates from the brazing filler metal located on the outer surface of the manifold with the wall thickness of 2 mm and propagates throughout the whole region of the brazing filler metal when the creep time reaches 34900 h. The creep life of the recuperator meets the requirement of 40000 h continuous operation when the wall thickness increases to 3.5 mm, but its total weight increases by 15%. Decreasing the minimum creep strain rate with the enhancement of the creep strength of the brazing filler metal presents an obvious effect on the creep life of the recuperator. At the same stress level, the creep rupture time of the recuperator is enhanced by 13 times if the mismatch between the minimum creep rate of the filler and base metal is reduced by 20%.

关键词: creep     life assessment     brazed joint     continuum damage mechanics     aeroengine recuperator    

Study of the mechanics of progressive collapse of FPB isolated beam-pier substructures

Jingcai ZHANG; Yong DING; Xinchun GUAN

《结构与土木工程前沿(英文)》 2022年 第16卷 第6期   页码 718-728 doi: 10.1007/s11709-022-0815-3

摘要: The horizontal stiffness of the isolated layer is reduced substantially by a friction pendulum bearing (FPB) toprotectthe structure from potential damages caused by earthquakes. However, horizontal stiffness is essential to progressive collapse resistance of structures. This paper presents a simplified model to assess the progressive collapse response of beam-pier substructure isolated by FPB. Progressive collapse resistance by flexural action of the beam and additional resistance owing to the horizontal restraining force was achieved. The influences of the equivalent radius and friction coefficient of the FPB, the applied axial force on the FPB, and span-depth ratio of the beam on the additional resistance were investigated. Simulations were conducted to verify the proposed model. The results show that progressive collapse resistance provided by horizontal restraining can be reduced as large as 46% and 88% during compressive arching action (CAA) and catenary action (CA), respectively. The equivalent radius of the FPB shows limited effect on the progressive collapse response of FPB isolated structures, but friction coefficient and applied axial force, as well as depth ratio of the beam, show significant influences on the additional progressive collapse resistance capacity. Finite element method (FEM) results are in good agreement with the result obtained by the proposed method.

关键词: friction pendulum bearing     progressive collapse     horizontal stiffness     compressive arching action     catenary action    

Advances in structural mechanics of Chinese ancient architectures

YU Maohong, ODA Yoshiya, FANG Dongping, ZHAO Junhai

《结构与土木工程前沿(英文)》 2008年 第2卷 第1期   页码 1-25 doi: 10.1007/s11709-008-0002-1

摘要: Chinese ancient architectures are valuable heritage of ancient culture of China. Many historical building have been preserved up to now. The researches on the structural mechanics of ancient architectures show the different aspects of structure and mechanics. Systematical studies on the structural mechanics of ancient architectures have been carried out at Xi’an Jiaotong University since 1982. It is related with the need of repair of some national preservation relics in Xi’an. These studies include: 1) Ancient wooden structures including three national preservation relics Arrow Tower at North City Gate, City Tower at East City Gate, and Baogao Temple in Ningbao, Zhejiang province. 2) Ancient tall masonry building, the Big Goose Pagoda and Small Goose Pagoda in Xi’an. 3) Mechanical characteristics of ancient soil under foundation and city wall; the influence of caves in and under the ancient City Wall on the stability of the wall. 4) The typical Chinese ancient building at the center of city: the Bell Tower and Drum tower. 5) The behavior of Dou-Gong and Joggle joint of Chinese ancient wooden structure. 6) The mechanical behavior of ancient soils under complex stress state. A new systematical strength theory, the unified strength theory, is used to analyze the stability of ancient city wall in Xi’an and foundation of tall pagoda built in Tang dynasty. These researches also concern differential settlements of Arrow Tower and resistance to earthquake of these historical architecture heritages. Some other studies are also introduced. This paper gives a summary of these researches. Preservation and research are nowadays an essential requirement for the famous monuments, buildings, towers and others. Our society is more and more conscious of this necessity, which involves increasing activities of restoration, and then sometimes also of repair, mechanical strengthening and seismic retrofitting. Many historical buildings have in fact problems of structural strength and stability; the need for further studies on structural mechanics and materials is definitely growing.

广义塑性力学及其运用

郑颖人,孔亮

《中国工程科学》 2005年 第7卷 第11期   页码 21-36

摘要:

分析了经典塑性力学用于岩土类材料的问题,它采用了3个不符合岩土材料变形机制的假设。从固体力学原理直接导出广义塑性位势理论,将经典塑性力学改造为更一般的塑性力学——广义塑性力学。广义塑性力学采用了塑性力学中的分量理论,能反映应力路径转折的影响,并避免了采用正交流动法则所引起的过大剪胀等不合理现象,也不会产生当前非关联流动法则中任意假定塑性势面引起的误差。给出了广义塑性力学的屈服面理论、硬化定律和应力-应变关系,并建立了考虑应力主轴旋转的广义塑性位势理论。屈服条件是状态参数,也是试验参数,只能由试验给出。应用表明,广义塑性力学可作为岩土材料的建模理论,还可应用于诸如极限分析等土力学的诸多领域,具有广阔的应用前景。

关键词: 岩土塑性力学     广义塑性力学     塑性势     屈服面     本构模型    

A computational toolbox for molecular property prediction based on quantum mechanics and quantitative

《化学科学与工程前沿(英文)》 2022年 第16卷 第2期   页码 152-167 doi: 10.1007/s11705-021-2060-z

摘要: Chemical industry is always seeking opportunities to efficiently and economically convert raw materials to commodity chemicals and higher value-added chemical-based products. The life cycles of chemical products involve the procedures of conceptual product designs, experimental investigations, sustainable manufactures through appropriate chemical processes and waste disposals. During these periods, one of the most important keys is the molecular property prediction models associating molecular structures with product properties. In this paper, a framework combining quantum mechanics and quantitative structure-property relationship is established for fast molecular property predictions, such as activity coefficient, and so forth. The workflow of framework consists of three steps. In the first step, a database is created for collections of basic molecular information; in the second step, quantum mechanics-based calculations are performed to predict quantum mechanics-based/derived molecular properties (pseudo experimental data), which are stored in a database and further provided for the developments of quantitative structure-property relationship methods for fast predictions of properties in the third step. The whole framework has been carried out within a molecular property prediction toolbox. Two case studies highlighting different aspects of the toolbox involving the predictions of heats of reaction and solid-liquid phase equilibriums are presented.

关键词: molecular property     quantum mechanics     quantitative structure-property relationship     heat of reaction     solid-liquid phase equilibrium    

钱学森与力学

谈庆明

《中国工程科学》 2001年 第3卷 第10期   页码 1-6

摘要:

介绍了钱学森先生在近代力学和技术科学发展中的贡献,特别是介绍了他为实现超声速飞行和火箭技术在一系列关键问题上所做的贡献。在研究过程中他不断开创出工程控制论、物理力学和喷气推进学等新的技术科学,从而促进了航空航天技术的飞跃发展。我们要学习体现在他身上的超前意识和务实精神,学习、理解并大力开展他所倡导的技术科学的研究工作。

关键词: 钱学森     力学     技术科学    

Analysis of actuating mechanics characteristics for a flexible miniature robot system

YU Lianzhi, YAN Guozheng, MA Guanying, ZAN Peng

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 66-70 doi: 10.1007/s11465-008-0006-5

摘要: Based on the inchworm movement, a miniature endoscope inspection robot system with a flexible structure is designed. The system is actuated by a pneumatic rubber actuator with three degrees of freedom, and it holds its position by air chambers. The actuating mechanics characteristics of the robot are analyzed. An electro-pneumatic pressure system is designed to control the motion of the robot. Results of the calculation and experiments are consistent, and the robot system can move smoothly in a soft tube.

关键词: calculation     consistent     endoscope inspection     electro-pneumatic     miniature endoscope    

矿山岩体力学及工程的研究进展与展望

谢和平

《中国工程科学》 2003年 第5卷 第3期   页码 31-38

摘要:

文章针对采矿工程的实际问题,综述了矿山岩体力学理论与应用的研究进展,主要内容包括矿山岩体力学的损伤研究与应用、矿山岩体力学的分形研究与应用和矿山岩体力学损伤与分形研究的工程应用;讨论了矿山岩体力学今后的研究方向,即深部开采带来的工程灾害防治、开采方法选择的科学问题与关键技术措施。

关键词: 矿山岩体力学     研究现状     展望    

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

《农业科学与工程前沿(英文)》 2023年 第10卷 第4期   页码 503-509 doi: 10.15302/J-FASE-2023528

摘要:

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

关键词: GREEN     AGRICULTURAL     PROMOTE     POLLUTION     SOURCE     DEVELOPMENT     POINT     STRENGTHENING     CONTROL    

我国农业生产的发展方向:从机械化到智慧化

罗锡文,廖娟,臧英,区颖刚,汪沛

《中国工程科学》 2022年 第24卷 第1期   页码 46-54 doi: 10.15302/J-SSCAE-2022.01.005

摘要:

“谁来种地,怎样种地”是中国和全世界农业生产面临的共同问题。改革开放以来,我国农业生产的机械化水平已显著提高;而农业生产智慧化是今后社会发展的必然趋势,将以智能装备为基础,以数据和知识为核心要素,使现代科学技术与农业深度融合,实现农业生产全过程的数字化感知、智能化决策、精准化作业和智慧化管理,进一步大幅提高劳动生产率、土地产出率和资源利用率。本文以水稻生产为例介绍了我国农业生产的发展现状,分析了我国农业生产向智慧化生产转变的必要性,总结了我国农业生产向智慧化发展面临的机遇与挑战,据此提出了我国农业生产的发展方向和发展路线。为促进我国农业生产方式从机械化向智慧化转变,本文提出了加强农机装备研发和创新体系建设、加强农机推广体系建设、加强农机社会化服务体系建设、加快智慧农业示范区建设等对策建议。

关键词: 农业生产     水稻生产     农业机械化     信息技术     智能农机     农业生产智慧化    

A regularization scheme for explicit level-set XFEM topology optimization

Markus J. GEISS, Jorge L. BARRERA, Narasimha BODDETI, Kurt MAUTE

《机械工程前沿(英文)》 2019年 第14卷 第2期   页码 153-170 doi: 10.1007/s11465-019-0533-2

摘要: Regularization of the level-set (LS) field is a critical part of LS-based topology optimization (TO) approaches. Traditionally this is achieved by advancing the LS field through the solution of a Hamilton-Jacobi equation combined with a reinitialization scheme. This approach, however, may limit the maximum step size and introduces discontinuities in the design process. Alternatively, energy functionals and intermediate LS value penalizations have been proposed. This paper introduces a novel LS regularization approach based on a signed distance field (SDF) which is applicable to explicit LS-based TO. The SDF is obtained using the heat method (HM) and is reconstructed for every design in the optimization process. The governing equations of the HM, as well as the ones describing the physical response of the system of interest, are discretized by the extended finite element method (XFEM). Numerical examples for problems modeled by linear elasticity, nonlinear hyperelasticity and the incompressible Navier-Stokes equations in two and three dimensions are presented to show the applicability of the proposed scheme to a broad range of design optimization problems.

关键词: level-set regularization     explicit level-sets     XFEM     CutFEM     topology optimization     heat method     signed distance field     nonlinear structural mechanics     fluid mechanics    

装备与信息协同促进现代智慧农业发展研究

韩佳伟,朱文颖,张博,赵春江,杨信廷

《中国工程科学》 2022年 第24卷 第1期   页码 55-63 doi: 10.15302/J-SSCAE-2022.01.007

摘要:

农业机械装备是现代农业发展的物质基础、农业机械化发展的重要标志,新一代信息技术驱动农业机械装备智能化转型升级;基于装备与信息技术协同的智慧农业成为现代农业发展的新趋势,对提高农业生产效率、推动农业机械优质高效发展具有积极意义。本文对比分析了国内外智慧农业的研究现状,梳理了我国农业机械装备、农业信息技术的研究进展与趋势;在剖析我国现代智慧农业发展需求并前瞻发展价值的基础上,提出重点工程发展建议:农业生态系统监测网络新基建工程、国家农业大数据中心及运行机制构建工程、智能农机装备研发应用工程、农业信息服务示范工程、果蔬商品化处理智能感控技术与装备研发示范工程。研究认为,立足国情加大农业科技创新投入并优化结构、建立农业“产学研”创新联盟、完善农业科技创新激励政策,可为引导现代智慧农业发展提供坚实保障。

关键词: 农业装备     农业信息化     农业信息服务     智能农机     新基建    

标题 作者 时间 类型 操作

Goryachkin’s agricultural mechanics

Vera CHINENOVA

期刊论文

Progressive failure analysis of notched composite plate by utilizing macro mechanics approach

期刊论文

航空航天技术与力学

陈士橹

期刊论文

Creep life assessment of aero-engine recuperator based on continuum damage mechanics approach

期刊论文

Study of the mechanics of progressive collapse of FPB isolated beam-pier substructures

Jingcai ZHANG; Yong DING; Xinchun GUAN

期刊论文

Advances in structural mechanics of Chinese ancient architectures

YU Maohong, ODA Yoshiya, FANG Dongping, ZHAO Junhai

期刊论文

广义塑性力学及其运用

郑颖人,孔亮

期刊论文

A computational toolbox for molecular property prediction based on quantum mechanics and quantitative

期刊论文

钱学森与力学

谈庆明

期刊论文

Analysis of actuating mechanics characteristics for a flexible miniature robot system

YU Lianzhi, YAN Guozheng, MA Guanying, ZAN Peng

期刊论文

矿山岩体力学及工程的研究进展与展望

谢和平

期刊论文

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

期刊论文

我国农业生产的发展方向:从机械化到智慧化

罗锡文,廖娟,臧英,区颖刚,汪沛

期刊论文

A regularization scheme for explicit level-set XFEM topology optimization

Markus J. GEISS, Jorge L. BARRERA, Narasimha BODDETI, Kurt MAUTE

期刊论文

装备与信息协同促进现代智慧农业发展研究

韩佳伟,朱文颖,张博,赵春江,杨信廷

期刊论文