检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

俄国·蒙古·中国

俄国·蒙古·中国

作者：巴德利(Baddeley j.f.)

来源：南通市图书馆图书评论

学校读者我要写书评

暂无评论

俄国·蒙古·中国

俄国·蒙古·中国

作者：巴德利(Baddeley j.f.)

来源：南通市图书馆图书评论

学校读者我要写书评

暂无评论

俄国·蒙古·中国

俄国·蒙古·中国

A LOOP DRAWBEAD RESTRAINING fORCE MODEL IN SHEET METAL DEEP DRAWING PROCESS

作者：巴德利(Baddeley j.f.)

来源：南通市图书馆图书评论

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2001年第5期14卷 380-386页

作者： Y.j. Luo, S.P. Li, j.f. Zheng, D.N. He, Y.Q. Zhang, j.L. Cheng and j. Y. jiang 1)National Mold & Die CAD Engineering Research Center, Shanghai 200030, China 2)Shanghai Volkswagen Automotive Company Ltd.(SVM), Shanghai 201805, China Shanghai jiaotong Univ. Shanghai 200030 China

In sheet metal forming, drawbeads are often used to control uneven material flow which may cause defects such as wrinkles, fracture, surface distortion and springback. Appropriate setting and adjusting the drawbead force is one of the most important pa- rameters in sheet metal forming process control. This paper derives the model of loop drawbead restraining force (DBRf) using plastic forming theory, and gives the min imum blankholding force. Experiments are carried out to verify the proposed DBRf model. The good agreement between the calculated values and experiments data justi- fies the proposed loop drawbead restraining force model.

关键词： drawbead restraining force sheet metal deep drawing

An SBfEM-Based Model for Hydraulic fracturing in Quasi-Brittle Materials

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2018年第4期31卷 416-432页

作者： f. Yao Z.j. Yang Y.j. Hu College of Civil Engineering and Architecture Zhejiang University Hangzhou 310058 China School of Civil Engineering Shaoxing University Shaoxing 312000 China

A numerical model based on the scaled boundary finite element method is devel- oped to simulate the hydraulic fracturing in concrete-like quasi-brittle materials using cohesive interface elements. The shadow domain method developed previously （Yang and Deeks in Eng fract Mech 143（4）：333 354, 2007） is extended to consider crack-width-dependent hydraulic pres- sure and cohesive traction, so that the stress intensity factors caused by both crack-face forces are semi-analytically calculated separately in the same way. The crack propagation is determined by the criterion of KI ≥ 0, and the propagation direction by the linear elastic fracture mechanics criteria. Two examples of concrete structures are modeled, and the results are in good agreement with the experimental data and others numerical results.

关键词： Scaled boundary finite element method Hydraulic fracture Cohesive crackmodel Crack propagation

Optimal use of mobile cooling units in a deep-level gold mine

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International journal of Mining Science and Technology 2020年第4期30卷 547-553页

作者： H.j.van Staden j.f.van Rensburg H.j.Groenewald Centre for Research and Continued Engineering Development North-West UniversityPretoria 0081South Africa

The South African gold mining sector remains a significant contributor to the country’s *** several challenges that hinder the realisation of South Africa’s full mineral potential,the sector’s sustainability and profitability can be enhanced through implementing operational improvement *** cooling units(MCUs)were identified as a potential focus area for operational *** are used as tertiary or in-stope cooling in hot underground *** this paper,a method was presented to characterise the performance of existing MCUs based on three key performance indicators(KPIs),namely,the wet-bulb temperature ratio(WTR),efficiency and *** strategies were then elected and implemented based on these *** implementation of this method in a South African gold mine attained a reduction in pumped water volumes,reduced operating costs through electricity cost savings and improvements in underground ventilation air temperatures.

关键词： Mobile cooling units Optimisation Mine cooling performance Electricity cost savings Spot cooling

Boundary discontinuous fourier analysis of thick beams with clamped and simply supported edges via CUf

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Aeronautics 2017年第5期30卷 1708-1718页

作者： f.G.CANALES j.L.MANTARI faculty of Mechanical Engineering Universidad de Ingenieriay Tecnologia ( UTEC) Lima 15063 Peru Department of Mechanical Engineering University of New Mexieo Albuquerque 87131 USA

This paper presents an analytical solution for static analysis of thick rectangular beams with different boundary conditions. Carrera＇s Unified formulation（CUf） is used in order to consider shear deformation theories of arbitrary order. The novelty of the present work is that a boundary discontinuous fourier approach is used to consider clamped boundary conditions in the analytical solution, unlike Navier-type solutions which are restricted to simply supported *** equations are obtained by employing the principle of virtual work. The numerical accuracy of results is ascertained by studying the convergence of the solution and comparing the results to those of a 3D finite element solution. Beams subjected to bending due to a uniform pressure load and subjected to torsion due to opposite linear forces are considered. Overall, accurate results close to those of 3D finite element solutions are obtained, which can be used to validate finite element results or other approximate methods.

关键词： Analytical solution Beam Clamped fourier Unified formulation

New Nanocomposite Materials by Incorporation of Nanocrystalline TiO_2 Particles into Polyaniline Conductive films

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2014年第5期30卷 449-454页

作者： f.j.f.liciano O.C.Monteiro Department of Chemistry and Biochemistry and CQB Faculty of SciencesUniversity of LisbonCampo Grande1749-016 LisbonPortugal

This work is focused on the combination of two building-blocks, nanocrystalline TiO2 particles and polyaniline conductive films （PAni）. The preparation of new nanostructured composite materials, displaying electron- and proton-conductive properties, to be used for the fabrication of new and superior energy storage devices was envisaged. The semiconducting TiO2 nanoparticles were obtained by means of a hydrothermal route. The PAni films were prepared on glassy carbon electrodes by electrochemical polymerization, under potential dynamic conditions. After characterization by X-ray diffraction, transmission electron microscopy or scanning electron microscopy and electrochemical techniques, the nanocrystalline particles were immobilized in the polymer matrix. The incorporation of the TiO2 was achieved using two distinct approaches： during the polymer growth or by deposition over previously prepared PAni films. The results demonstrate that the PAni morphology depends on the experimental conditions used during the polymer growth. After TiO2 immobilization, the best electrochemical response was obtained for the nanocomposite structure produced through the TiO2 incorporation after the PAni film synthesis. The modified electrodes were structurally and morphologically characterized and their electro-catalytic activity towards the hydrogen evolution reaction was analyzed. A new electrochemical performance related with the oxidation of molecular hydrogen entrapped in the PAni-TiO2 matrix was observed for the modified electrode after TiO2 incorporation. This behavior can be directly associated with the synergetic combination of the TiO2 and PAni, and is dependent on the amount of the semiconductor.

关键词： PolyaniHne (PAni) Nanosized TiO2 Nanocomposites Hydrogen trapping

Vibrational behavior of isotropic plate structures in contact with a bounded fluid via unified formulation

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Aeronautics 2019年第4期32卷 921-937页

作者： f.G.CANALES j.L.MANTARI faculty of Mechanical Engineering Instituto de Investigación en Ingeniería Naval(IDIIN)Universidad Nacional de Ingenieria(UNI) Department of Mechanical Engineering University of New Mexico

This paper presents an analytical solution for free vibration analysis of thick rectangular isotropic plates coupled with a bounded fluid for various boundary conditions. In order to consider displacement theories of an arbitrary order, the Carrera Unified formulation(CUf) is used. The eigenvalue problem is obtained by using the energy functional, considering plate and fluid kinetic energies as well as the potential energy of the plate. The Ritz method is used to evaluate the displacement variables, and the functions used in the Ritz series can be adjusted to consider any of the classical boundary conditions. The convergence of the solution is analyzed, and a validation of results considering open literature and 3D finite element software is performed. Parametric studies are carried out to obtain natural frequencies as a function of the side-to-thickness ratio, plate aspect ratio, fluid domain size, plate boundary conditions, and fluid-solid density ratio. Pressure and velocity in the fluid domain are evaluated in order to establish the consistency of the *** results for thick plates are obtained with a much lower computational cost compared to that of 3D finite element solutions.

关键词： Added mass fluid-structure interaction Plate Ritz method Unified formulation Vibration