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10 December 2010, Volume 32 Issue 6
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    Education Study
    2010, 32(6):  80-82.  doi:10.6052/1000-0879-lxysj2009-429
    Abstract ( 1187 )   PDF (406KB) ( 435 )  
    Axial force diagram for general frame can be obtained from bending-moment diagram and shear force diagram,but some axial forces can not be obtained from using the shear force diagram directly when axial force was hyper-static.Through analysising the structural features,putting forward to a new method,the method combines the characteristic of which only the pillar exists axial force when axial concentrated force acts on the pillar's joint with mechanical means.Example shows the method has spontaneous and convenient to computing. Key words: hyper-static frame; axial force; computational method.
    2010, 32(6):  73-75.  doi:10.6052/1000-0879-lxysj2009-475
    Abstract ( 752 )   PDF (578KB) ( 303 )  
    A railway tunnel in southwest china is 8.5Km .It has a complex geological condition.According to remote sensing and survey and reconnoitre in the various phase,the geological condition of the tunnel is been examined.The faultage of the tunnel and the stress of the earth and the water under the earth is been found out.So the foundation is been offered for the design and construction of the tunnel.
    Education Study
    2010, 32(6):  96-99.  doi:10.6052/1000-0879-lxysj2010-026
    Abstract ( 1576 )   PDF (861KB) ( 652 )  
    Based on the Third National structural design competition for College Students, the design and the production process of the participative work submitted by Zhejiang University are described. The proposition of current structural design competition, compared with the previous, introduced the multi-disciplinary overlapping elements with the desitination of the design and production of wind power generation power. Apart from sufficient load capacity and stiffness for sturcture, and also the greatest possible wind turbine capacity is required, so model design and production is extremely difficult. unioned the theory and the practice, The Zhejiang University participating team designed and manufactured the wind power generation tower which adapts with this session of competition test condition, and made the outstanding progress. The design mentality and the model manufacture method provided in this article have certain reference value to the structural design competition.
    2010, 32(6):  22-26.  doi:10.6052/1000-0879-lxysj2010-038
    Abstract ( 942 )   PDF (868KB) ( 706 )  

    The dynamic analysis of multibody systems is carried out in this paper based on Gauss constraint principle, for a family of multibody open loop chain structures.  Gauss constraint method is used to derive the dynamic equation of multibody chain structures, in a symbolic derivation process, and the analytic expressions of the dynamic equation are obtained in closed form. By taking the rigid and flexible structures as examples, the time used for symbolic derivation of dynamic equations is analyzed for different analysis methods and degrees of freedom. It is shown that Gauss constraint method is more suitable for symbolic derivation of dynamic equations of multibody structures compared with Lagrange's method. Furthermore, the calculation advantage of Gauss constraint method increases with the increase of degrees of freedom.

    2010, 32(6):  106-109.  doi:10.6052/1000-0879-lxysj2010-114
    Abstract ( 2386 )   PDF (949KB) ( 675 )  
    This comprehensive and systematic introduction to the mechanics and engineering structures Master Professor Timoshenko content of academic activities and books for study and research, Professor Timoshenko and his writings provide important information for
    2010, 32(6):  33-38.  doi:10.6052/1000-0879-lxysj2010-117
    Abstract ( 1324 )   PDF (1454KB) ( 529 )  
    Based on the dynamic simulation of the arch thin shell, an optimal design model for the thickness of the constraint damping layers is proposed for minimizing structural vibration and noise with the weight constraints. The K-S function is adopted to obtain the vibration acceleration level (VAL), which is used as the evaluation parameter to measure the reduction effect of vibration and noise. The response surface methodology (RSM) is used to fit the VAL. The error testing is used to find a better response surface curve fitting, whose fitting is more accurate by narrowing the scope of the variable appropriately to adjust the errors. After using the Quadratic Programming for the optimization model, the
    first natual frequency of the structure is increased by 22.97{\%}, the VAL of the structure is reduced by 12.96{\%}, and  the whole structure sees a great improvement.
    2010, 32(6):  69-72.  doi:10.6052/1000-0879-lxysj2010-152
    Abstract ( 908 )   PDF (736KB) ( 385 )  
    The practical calculation formula for lateral buckling load of the tied-arch bridge with transverse braces in the railway passenger transport line is proposed using the Ritz approximation method. The trial displacement functions are assumed to satisfy the boundary conditions in lateral flexural torsion buckling conditions. The potential energy
    formulations for the arch bridge structure under lateral buckling conditions are determined. The critical lateral buckling load for the tied-arch bridge is deduced based on the minimal potential principle. As an example, the lateral buckling load for a tied-arch bridge in a railway passenger transport line is investigated using the proposed method. The comparison is made between the practical method and the buckling analysis of the finite element method. The result shows that the proposed method is easy to apply and can predict the critical lateral buckling load for the tied-arch bridge precisely.
    2010, 32(6):  54-59.  doi:10.6052/1000-0879-lxysj2010-155
    Abstract ( 861 )   PDF (5504KB) ( 410 )  
    In order to study the tensile failure  of rock bridge, the finite element software FEPG is used to simulate the tensile failure process of rock bridge with different angles. Under the condition of uniaxial compression, the simulation results show that for two sets of parallel pre-cracks with  same crack angle and distance, but with different inclination of rock bridge, the extension level of pre-crack is different. The bigger the inclination angle of rock bridge, the easier the rock bridge goes to tensile fracture.
    2010, 32(6):  39-42.  doi:10.6052/1000-0879-lxysj2010-163
    Abstract ( 977 )   PDF (633KB) ( 450 )  
    Based on an accurate mathematical model of the post-buckling of axially extensible rods, a numerical analysis of the post-buckling behavior of simply supported compressed FGM rods by a shooting method is presented in this paper. In the analysis, it was assumed that the material properties of the rods vary continuously as a power function of the thickness coordinate. The post-buckling characteristics curves of FGM rods under the different graded index are plotted, which are compared with the those of pure metal and ceramic material columns. The effects of the load, material gradient property and slender on the buckling deformation of beam are discussed in details.
    Education Study
    2010, 32(6):  43-48.  doi:10.6052/1000-0879-lxysj2010-188
    Abstract ( 1037 )  
    Using the results from the studies of C-Mn steel ductile fracture mechanisms and the laws of the stress-driven migration of point defects in a stress field, and with an analysis of the micro-process of ductile fracture induced by the vacancy coalescence at high temperatures, a relationship between the fracture toughness $J_{\rm IC}$ and temperature $T$ in the intermediate temperature range is derived from the vacancy concentration. Experimental data of fracture toughness of pressure vessel steels are analyzed. It is shown that there is a good agreement between the theoretical model and the experimental results.
    2010, 32(6):  27-32.  doi:10.6052/1000-0879-lxysj2010-205
    Abstract ( 965 )   PDF (990KB) ( 359 )  
    In order to study the fire behavior of large space steel structures, the buckling of steel components would be taken into consideration. In this paper, a constitutive model with buckling property of steel component is established for  finite element analysis of large space structures at high temperature. By studying the bending deformation of axially loaded steel components at various temperatures, the nominal axial stiffness of the steel components with buckling property is
    theoretically derived. Influence of slenderness ratio, initial imperfection, and critical load on the nominal axial stiffness is discussed. Using the energy balance method, the nominal axial stiffness is replaced by the equivalent stiffness. Then a bilinear stress-strain constitutive model of steel materials for steel components with buckling property is established. The model is verified by the numerical calculation.
    2010, 32(6):  49-53.  doi:10.6052/1000-0879-lxysj2010-226
    Abstract ( 914 )   PDF (7953KB) ( 270 )  

    The fatigue behavior of Low alloy steel in air and corrosion medium was studied by the fatigue tests. The S-N curves were obtained and the observations of flat surfaces and fatigue fractographs have been made. The results showed that the fatigue strength of Low alloy steel in corrosion medium was much lower than that in air. Fatigue cracks in air were initiated from the matrix of surface, while most of fatigue cracks in corrosion medium were initiated from pits. The typical feature of the fatigue crack propagation region in air was fatigue striations, while that in corrosion medium was intergranular crack characteristic. The fatigue limit in air could be predicted by empirical equation. The predicted fatigue limit was agreeable to the experimental fatigue limit.

    2010, 32(6):  124-125.  doi:10.6052/1000-0879-lxysj2010-299
    Abstract ( 853 )   PDF (458KB) ( 340 )  
    This paper analyses the original, structure, algorithm and related mechanical meaning of the computational problems of steelyard equilibrium in Shu Xue Yao. Furthermore, it shows that in late 17th century the Chinese mathematicians' cognition about the computational problems of lever equilibrium was deepened.
    2010, 32(6):  13-17.  doi:10.6052/1000-0879-lxysj2009-181
    Abstract ( 991 )   PDF (903KB) ( 541 )  

    The transport of different petroleum products through a single pipeline is known as batch transfer, which is the most common method in product transportation. A certain amount of mixing between products is called interface contamination. In order to ensure the quality of the products being transported, the mixing volume and the position of the mixing zone should be accurately predicted. This paper estimates the mixing volumes by using a two-dimensional model of convection-diffusion equation, which  is solved by a two step method to obtain numerical solutions in laminar flow and turbulent flow, as  a comparatively effective method. The results show that the mixing volume in turbulent flow is smaller than that in laminar flow, the distribution of the mean concentration in the cross section changes with time, and  the diffusion coefficient influences the mixing volume in turbulent flow.

    Education Study
    2010, 32(6):  76-77.  doi:10.6052/1000-0879-lxysj2009-450
    Abstract ( 887 )   PDF (556KB) ( 329 )  
    2010, 32(6):  78-79.  doi:10.6052/1000-0879-lxysj2009-377
    Abstract ( 1135 )   PDF (474KB) ( 425 )  
    2010, 32(6):  91-93.  doi:10.6052/1000-0879-lxysj2009-455
    Abstract ( 959 )   PDF (1192KB) ( 422 )  
    Essence course of structure modeling designing is introduced. Relationship of training of applied Talents in civil engineering with structure modeling competition is discussed. Based on it, the training system of applied talents is brought forward in some ways, such as strengthening practice course system, innovating content of courses, setting opening practice projects, etc. Some examples are introduced to attest the training system. Some results are drawn for craft brothers of other institutes.
    2010, 32(6):  88-90.  doi:10.6052/1000-0879-lxysj2010-024
    Abstract ( 1142 )   PDF (936KB) ( 511 )  
    The experiment aim to analyze the mechanic properties of paper members was done with pole and belt made by lead paper, It shows that there is a elastic liner segment in the stress-strain curve and the elasticity modulus are separated from one another but mainly between 200MPa~400MPa. The property cure of the paper belt is nonlinear. The large ultimate strain is between 0.015-0.025.The state of bonding has an significant effect on Ultimate Tensile Strain of the belt. The experiment result is helpful to the optimum design of paper structures.
    2010, 32(6):  83-84.  doi:10.6052/1000-0879-lxysj2009-300
    Abstract ( 877 )   PDF (394KB) ( 362 )  
    2010, 32(6):  100-101.  doi:10.6052/1000-0879-lxysj2009-135
    Abstract ( 1421 )   PDF (397KB) ( 1179 )  
    The bending strain proposition of both sides fixed supports beam under temperature change is a typical example of teaching “the qualitative structural mechanics”. Explained through this proposition's statement, had demonstrated the basic concept and the utilization technique of qualitative structural mechanics. These were helpful to the student understanding and grasping the basic principle and the method of the qualitative structural mechanics
    2010, 32(6):  8-12.  doi:10.6052/1000-0879-lxysj2010-087
    Abstract ( 861 )   PDF (1068KB) ( 332 )  

    The meshless method for unsteady flow involving large-scale moving boundaries is studied in this paper. A criterion for whether the point is to be deleted is established, the cloud is rebuilt by a filling method, and the state of the new point is calculated by a linear interpolation method, which serves as the local reestablishment of cloud for dealing with large scale moving points. The algorithm for solving ALE equations based on the meshless method is developed. On the basis of clouds, the spatial derivatives are approximated by using local least-squares curve fitting and the numerical flux is calculated with HLLC scheme, and a multistage Runge-Kutta algorithm is used to advance the equation in time. As an example, a moving piston is simulated, and the numerical results agree well with exact results.  In addition, the flow of airflow passing through a static column and the flow of a column moving in the static flow are simulated and compared with each other, and results indicate  that the method is valid.

    2010, 32(6):  60-63.  doi:10.6052/1000-0879-lxysj2009-171
    Abstract ( 860 )   PDF (688KB) ( 364 )  
    The paper studies the relations between the load acting on the simulative steel plate of stanchion and the ground
    sedimentations. The test determines the bearing safety of the ground. Based on the similarity criterion of the proportional reduction plate  the pneumatic impact tests were carried on. The test results can be used for studying and judging the bearing capacity of support plate acting on the ground and implementing a new impact method for simulating the equipment spot.
    2010, 32(6):  18-21.  doi:10.6052/1000-0879-lxysj2009-477
    Abstract ( 1111 )   PDF (5781KB) ( 354 )  
    Numerical hypervelocity impact experiments were carried out for spacecraft typical Whipple shield with lava simulated
    meteoroids. It is shown that during the hypervelocity impact, the damage on the back plate is manifested by the concentration of energy, and it  becomes more and more severe with the increase of impact velocity. The debris of the front plate also is an important damage element of the back plate, and the pits made by the debris are deep and big.
    Around the mechanics
    2010, 32(6):  1-7.  doi:10.6052/1000-0879-lxysj2010-437
    Abstract ( 1426 )   PDF (1944KB) ( 695 )  
    This paper will review the multi-physical fields coupled properties measurement technology and device for electromagnetic functional materials. It will be introduced how to measure the physical and mechanical properties including electric/magnetic hysteresis, butterfly curve, electrostriction/magnetostriction, stress-strain curve and magnetoelectric effect and so on under muti-physical fields coupled conditions. Then, new phenomena under under muti-physical fields coupled conditions for electromangetic functional materials will be described, which include electric hysteresis under the multi-axial electric field and biaxial mechanical loading, domain switch rule in crack tip, magnetic-induced pseudoelasticity, magnetostriction ``drop'' and so on. It has improtant meaning for understanding the deformation and fracture mechanism under coupled field for electromagnetic functional material and structure.
    2010, 32(6):  102-105.  doi:10.6052/1000-0879-lxysj2009-520
    Abstract ( 938 )   PDF (802KB) ( 392 )  
    Mechanics is one of the earliest developed subjects of physics in our country. Although symbol is not the main body of research during the process of the development of mechanics, it exerts crucial influence in all of the physics-related articles. As the knowledge of physics in western countries spread into China from late Ming dynasty to Qing dynasty, the use of symbols entered new era. This essay focuses on the use of the characters and symbols in articles translated by mathematician Li shanlan in late Qingdynasty and by western missionary Ding Weiliang. On the basis of the comparision and analasis of the articles, this essay will furthermore make a summary and then make some simple probe into it.
    2010, 32(6):  64-68.  doi:10.6052/1000-0879-lxysj2009-272
    Abstract ( 1162 )   PDF (783KB) ( 526 )  
    The finite element model is built up for the spanning pipeline composed of steel pipe and concrete lay by ANSYS software. The PIPE59 element, MATRIX27 element and COMBIN40 element are used to simulate coriolis force and centrifugal force due to internal flowing, and contact between the pipeline and sea bed. The displacements, stresses and natural frequencies of the pipeline are calculated with various span lengths. Then the model is verified by comparing with CAM and DNV engineering codes. The results identify that the ANSYS software can be used to simulate the response of the near-bed pipeline with internal and external flow. The method of building model should be used to engineering easily.