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Buckling analysis of super-long rock-socketed filling piles in soft soil area by element free Galerkin method

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Journal of Central South University of Technology 2007年第6期14卷 858-863页

作者：邹新军赵明华刘光栋 Institute of Geotechnical Engineering Hunan University

In order to discuss the buckling stability of super-long rock-socketed filling piles widely used in bridge engineering in soft soil area such as Dongting Lake, the second stability type was adopted instead of traditional first type, and a newly invented numerical analysis method, i.e. the element-free Galerkin method (EFGM), was introduced to consider the non-concordant deformation and nonlinearity of the pile-soil interface. Then, based on the nonlinear elastic-ideal plastic pile-soil interface model, a nonlinear iterative algorithm was given to analyze the pile-soil interaction, and a program for buckling analysis of piles by the EFGM (PBAP-EFGM) and arc length method was worked out as well. The application results in an engineering example show that, the shape of pile top load-settlement curve obtained by the program agrees well with the measured one, of which the difference may be caused mainly by those uncertain factors such as possible initial defects of pile shaft and the eccentric loading during the test process. However, the calculated critical load is very close with the measured ultimate load of the test pile, and the corresponding relative error is only 5.6%, far better than the calculated values by linear and nonlinear incremental buckling analysis (with a greater relative error of 37.0% and 15.4% respectively), which also verifies the rationality and feasibility of the present method.

关键词： super-long rock-socketed filling pile buckling analysis element free Galerkin method critical load

WEIGHTED SOLUTION OF SMALL-DEFLECTION BUCKLING EQUATION OF THIN SHELL

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Applied Mathematics and Mechanics(English Edition) 2001年第12期22卷 1404-1409页

作者：王宗利王熙郝文华 Department of Engineering Mechanics Shanghai Jiaotong University Shanghai P R China

Based on small-deflection buckling equation, a weighted solution for critical load is presented. Usually, it is very difficult to solve the equation for general problems, especially those with complicated boundary conditions, Axisymmetric problem was studied as an example. Influencing factors were found from the equation and averaged as the buckling load by introducing weights. To determine those weights, some special known results were applied. This method solves general complicated problems by using the solutions of special simple problems, simplifies the solving procedure and expands the scope of solvable problem. Compared with numerical solution, it also has fine precision.

关键词： shell buckling critical load weighted average

A NEW APPROACH TO PREDICTING INTERFACIAL CRACK GROWTH

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Applied Mathematics and Mechanics(English Edition) 1997年第1期18卷 37-44页

作者：胡互让吴承平 Department of Mechanical Aerospace and Manufacturing Engineering Syracuse University Syracuse U.S.A. Chongqing Jiaotong Institute Chongqing P.R. China

A new approach, called β=0 approach is presented for use in the prediction ofinlerfocial crack growth. This approach is a kind of transformation. It transforms anoscillatory stress field to a nonoscillatory case by adjusting the elastic constants of thematerials involved. The interface toughness locus is also changed according to the newmaterial properties. It is shown that this approach will predict the exact same criticalload as interfacial fracture mechanics does. Finally several examples are presented toshow how to enforce β=0 while keeping the energy release rate unchanged.

关键词： interfacial crack crack growth β=0 approach critical load

Geometrical nonlinear stability analyses of cable-truss domes

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Journal of Zhejiang University Science 2003年第3期4卷 317-323页

作者：高博青卢群鑫董石麟 DepartmentofCivilEngineering ZhejiangUniversityHangzhou310027China

The nonlinear finite element method is used to analyze the geometrical nonlinear stability of cable truss domes with different cable distributions. The results indicate that the critical load increases evidently when cables, especially diagonal cables, are distributed in the structure. The critical loads of the structure at different rise span ratios are also discussed in this paper. It was shown that the effect of the tensional cable is more evident at small rise span ratio. The buckling of the structure is characterized by a global collapse at small rise span ratio; that the torsional buckling of the radial truss occurs at big rise span ratio; and that at proper rise span ratio, the global collapse and the lateral buckling of the truss occur nearly simultaneously.

关键词： Cable truss dome Geometrical nonlinear stability analysis Parameter analysis Cable distribution critical load

Evaluation of Interfacial Adhesion Property for Thin Hard Films with Fuzzy Method

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Journal of Wuhan University of Technology(Materials Science) 2010年第5期25卷 829-831页

作者：朱强 School of Mechanical Engineering Zhengzhou University

According to nanoscratch results for the TiN film, an evaluation method for interfacial fracture toughness of thin hard films is presented with fuzzy concepts, which can account for such influential factors in scratch test as surface roughness and material imperfection. Based on configuration changes in scratching curves, the parameters RV and RF are defined as the relative ratios of tip vertical displacement and of friction coefficinet. Fuzzy features of the scratching curves are analyzed carefully. The critical load is deduced from fuzzy logic operations and used to calculate the value of interfacial fracture toughness. With this method, the interfacial fracture toughness of TiN/HSS is evaluated approximately as 4.18 MPam^1/2. Results show that the method is valid and can benefit the interfacial adhesion property investigation for thin hard films.

关键词： interfacial adhesion thin hard films critical load fuzzy evaluation

THE BUCKLED STATES OF ANNULAR SANDWICH PLATES

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Applied Mathematics and Mechanics(English Edition) 1992年第7期13卷 623-628页

作者：何录武程昌钧 Department of Mechanics Lanzhou University Lanzhou

In this paper, the axisymmetric buckled states of an annular sandwich plate ( Reissner-type sandwich plate) with the clamped inner edge which is subjected to a uniform radial compressive thrust at the clamped outer edge are studied. Firstly, the basic equation of the buckled problem is derived. Secondly, the critical loads for some parameters are obtained by using the shooting method. Finally, we discuss the existence of the buckled slates in the vicinity of the critical loads and obtain the asymptotic expansions of the buckled states.

关键词： sandwich plate shooting method critical load buckled state

RESEARCH ON IMPERFECTION SENSITIVE REGION OF SINGLE-LAYER LATTICED DOMES

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Transactions of Nanjing University of Aeronautics and Astronautics 2006年第4期23卷 243-249页

作者：唐敢王法武南京航空航天大学航空宇航学院

The concept of the imperfection sensitive region is given. The advanced stochastic imperfection method is used to research the imperfection sensitive region of single-layer latticed domes. Taking a K6 single-layer latticed dome with a diameter of 50 m as an example, its imperfection sensitive region is made up of the first 12 kinds of joints. The influence of the imperfections of support joints on the stability of the K6 single-layer latticed dome is negligible. Influences of the joint imperfections of the main rib and the secondary rib on the structural stability are similar. The initial deviations of these joints all greatly lower the critical load of the dome. Results show that the method can analyze the structural imperfection sensitive region quantitatively and accurately.

关键词： imperfection single-layer latticed dome imperfection sensitive region advanced stochastic imperfection method critical load

Analytic Solution of Elasto-Plastic Stress in Infinite Slope under Uniform load

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China Ocean Engineering 1999年第2期14卷 197-208页

作者： Wang, NX Gu, L Nanjing Hydraul Res Inst Geotech Engn Dept Nanjing 210024 Peoples R China Lianyungang Port Author Plan & Stat Dept Lianyungang 222046 Peoples R China

According to the Mohr-Coulomb yield criterion, the stress field of the infinite slope is derived under a vertical uniform load q on the top of the slope. It is indicated that elastic and elasto-plastic states would occur in the slope. When q is smaller than the critical load, q(p), the slope is in the elastic state. If q equals q(p), the slope is in the critical state, and the plastic deformation would occur along the critical angle. With the increase of q, the plastic zone would extend, and the slope is in the elasto-plastic State. If q equals limit load, the slope is in the limit equilibrium state. The slope may be divided into three zones. Some charts of the critical angle, the critical and limit load coefficients are presented in this paper.

关键词： elasto-plastic stress critical load limit load infinite slope uniform load

load shedding scheme for the two-area system with linear quadratic regulator

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Frontiers in Energy 2013年第1期7卷 90-102页

作者： D. TYAGI Ashwani KUMAR Saurabh CHANANA Department of Electrical Engineering National Institute of Technology Kurukshetra 136119 India

The power system is prone to many emergency conditions which may lead to emergency state of operation with decay in the system frequency. The dramatic change in the frequency can result in cascaded failure of the system. In order to avoid power system collapse, load shedding （LS） schemes are adopted with the optimal amount of load shed. This paper proposed a methodology in a two-area thermal-thermal system for finding the required amount of load to be shed for setting the frequency of the system within minimum allowable limits. The LS steps have been obtained based on the rate of change of frequency with the increase in load in steps. A systematic study has been conducted for three scenarios： the scheme with a conventional integral controller; the scheme with a linear quadratic regulator （LQR）; and the scheme with an LQR and superconducting magnetic energy storage devices （SMES）. A comparison of the results has been presented on the two-area system.

关键词： critical load frequency response load shed- ding (LS) multi-area system rate of change of frequency linear quadratic regulator (LQR) superconducting magnetic energy storage devices (SMES)