Experimental Analysis of Bearing Capacity of Triangle Hollow Flange Beam

On the basis of Hollow Flange Beam (HFB) which is proposed by Australian researchers, a new pattern triangle hollow flange beam (THFB) is presented. According to the experimental test and finite element simulation, the failure processes of THFB and traditional I-beam under concentrated load are compared, and then the obvious differences between the failure modes of these two type beams are founded. The local buckling is easily occurred for the THFB, while overall instability is easily occurred for traditional I-beam, and THFB possesses have better bending performance and twist resistance than those of traditional I-beam. with the experiments, finite element analysis is carried out by FE software ANSYS, and the FE results agree with the test results. Based on FE models, the parameter analysis is carried out for THFB. The parameters mainly include the thickness of top flange, the width of top flange, the thickness of web and the yield strength of steel. The change rule of the bearing capacity of THFB with different parameters can be achieved by parameter analysis. Finally, based on the above results, the applicability of the calculation formula of Eurocode3 to compute the bearing capacity of THFB is discussed. The results show that it is safe and reliable to adopt the calculation formula of Eurocode3 to compute the bearing capacity of THFB, Whilst the estimation is relatively conservative.     

Computation of Natural Frequencies of a Rotating Beam

On Kane's dynamic equation,the ordinary finite element dynamic equation of a rotating beam is developed,and the apparent three dimension element matrices are obtained. Finally the natural frequencies of a rotating beam are figured out and compared with those of ordinary method.     

Experiment and FEM Analysis on the Joint of Inserted Steel Beam

A new composite structure which is composed of steel beam and concrete girder is introduced in fuel electric plant construction. With different height of concrete girders with or without anchor bar, two scale models from an actual project were designed and tested. It is shown that the maximum restraining moment of ends of steel beams is approximately 60kN*m; influence of anchor bar is little; the one with 600mm high concrete beam is damaged by shear, and the others steel beam is damaged by bending failure. Finite element models were built for supplementary analysis, and the result indicates that critical value of the height of concrete beam of different failure modes is 700mm; stiffness of shear key and thickness of floor have great influence on the structure; size of anchor bar has little influence; and width of the end of the steel beam has certain influence.     

Finite Element Analysis of Shear Behavior of Super High Strength Reinforced Concrete Beam

On the basis of testing results of shear behavior from 18 super high strength reinforced concrete restrained beams with web reinforcement, with the cube compressive strength ranging from over 100Mpa, in this paper, the nonlinear finite element analysis procedure was formulated and the analysis of the specimen tests was carried out with the parameters obtained from the experiments and improved constitutive model and failure criteria of materials. Based on the simulated shear resistance test results and practical measured data of eighteen super high strength concrete restrained beams under point load, the equation to compute the shear resistance capacity of such beams was thus obtained by regression. The analytical results agree well with those of experiments.     

Evaluation of the Energy Release Rate of Three-point-bending Beam Using Finite Element Method

Calculation of the energy release rate with finite element method (FEM ) is conducted. The concrete beam model is meshed using a method without need of considering the crack-tip singular element. Two columns of nodes, which belong to the right-and left-parts of the beam, respectively, are generated on the central line of the model and released one after another in a proper sequence. Energy release rate is evaluated based on the virtual crack closure technique. Comparison between the calculated values and theoretical values is made, which shows that they are in good agreement.     

Measurement and Analysis of Prestressed Concrete Flat Beam- Waffle Slab System During Prestressing

During the pre - stressing of the unbonded prestressed concrete wide flat beam - waffle slab system, the displacements and strains of slab and the prestressed concrete beams were site - measured and the results were analyzed. The prestressing construction was simulated by finite element program. The prestressing efficiency of the unbonded prestressed concrete wide flat beam - waffle slab system was discussed. It indicates that the prestressing efficiency was affected by the in -plane stiffness of slab.     

Study on the Key Construction Techniques about the Prestressed Transform Beam of Chongqing People''s Mansion

In order to ensure the construction quality of the massive prestressed transform beam, to prevent and control the cracking before tensioning ,the technology of casting ,methods of temperature and crack controlling are carefully analysed and theoretical calculation is carried out as well as the temperature inspection during construction ,all of which have effective results. Some prestressed construction points of transform beam are also introduced in this article, and reference advices are given at last.     

沿海滩涂发展能源植物的潜力分析

发展生物质能源对缓解中国的矿质能源压力、减轻能源污染具有重要意义。在分析了发展生物质能源的迫切性的基础上,介绍了利用中国丰富的沿海滩涂土地资源和植物资源开发能源植物的潜力。同时,从滩涂资源的有效利用、盐生植物中能源植物的发掘和通过转基因技术提高能源植物耐盐性及改良盐生植物生产能源物质的特性等方面提出了沿海滩涂发展能源植物的资源潜力。     

Finite Element Analysis and Experimental Research on Pedestal of PC Beam for Light Railcar

In design of light railcar used freely supported beam, the cast steel pedestals will bear complex loads, which include weight, acceleration and wind, etc. Because of pedestals' peculiarity and complexity, the strength of the pedestals play an important role in safety of light railcar. So it's necessary to analyze their stress and deformation in order to insure safety of light railcar. Up to now, finite element analysis is still the most effective means. By studying cast steel pedestal with finite element method, 3-D finite element models of fixed and kinetic pedestals were built, and the loads and boundary condition of pedestals were analyzed. By means of finite element analysis software, the contact and von mises stresses were obtained and deformation were resolved. As a result of analysis, the tow of pedestal can fulfill requirement of use in light railcar, the contact stress and von mises stress are not exceeded limit stress strength of materials. There is enough static strength for the structures of pedestals. For verifying theoretical analysis result, the fatigue test was carried out, with examining the testing points locating on the pedestals, the stress and deformation data were measured. By comparing between theoretical analysis and test data, the experimental results show calculated and testing results can meet the case well which assure the reliability of finite element analysis. But in the result, there are differences in deformations of them. The reason may be that boundary conditions and loads are not same between analysis and experiment.     

石河子垦区蟠桃气候品质评价方法研究

通过建立蟠桃气候品质模型,为开展蟠桃气候品质气象认证和区域优势气候资源开发等提供技术支撑。本文以影响蟠桃品质的气候适宜性、生长期的气象条件、气象灾害及生产管理措施为主要指标,建立蟠桃气候品质评价指标及模型。以模型为基础,结合果园取样检测结果,确定2018年蟠桃气候品质评价结果为优。     

Finite Element Simulate Analysis of Small Span-to Depth Ratio Coupling Beams with Special Reiforcement

Test investigations show that the reinforcement scheme with adding diagonal and rhombic bars to traditional reinforcement in the foundation is an ideal way, for the seismic performance of small span-to depth ratio coupling beams with this scheme is better than that of traditional reinforcement. Because the regions in the small aspect ratio coupling beam belong to D-regions, in which the Bernoulli hypothesis of plane strain distribution is invalid, the traditional bending theory can not be used. This paper simulates the coupling beam through non-linear finite element analysis program, and contrasts the analysis result of the bar's stress distribution with test result. The contrast results confirm that it is a valid way to analyse the bar's stress distribution in this coupling beam through non-linear finite element analysis program.     

The Direction Characterisitic of Stress Gradient in Crack Structure and Three-Dimensional Line-type Element

Analysis is given to the direction characteristic of stress gradient in crackstructure by using three-dimensional line-type element,The purpose is considerably to reduce theoperation of computation and improve the computation precision in finite element analysis.     

Analysis on PC Box Beam Webs by Vertical Prestress in Consideration of Stress Diffusion

In order to study the stress distribution effect of the webs which is under the action of vertical prestress, pairs of forces were acted on a long and narrow rectangular thin plate, and the webs stress field under the effect of vertical prestressing was simulated, with analytical solution of vertical normal stress derived and the numerical solution obtained by the Least-square method. The parameters,λ and κ, were introduced and calculated to describe vertical stress uniformity and stress level, which shows that λand κ value are more sensitive to webs vertical reinforcement spacing. On the premise of uniformity of vertical prestress and stress level, the fitting diffusion angle of vertical prestress acting on the webs is obtained and fitted by polynomial. Vertical prestress diffusion effect of the webs was tested in bridge site and analyzed by the finite element software. The results show that the webs stress diffusion is obvious, and the stress has a good uniformity at the section of H/2 but a bad uniformity at axillary and shore up.     

Design Method for Bending Buckling of Web in Aluminum Beam

As for the local buckling of aluminum bending members, a finite element analysis of the stability of aluminum plates under bending was performed. Compared with the results of codes’ method and finite element method, the advantages and disadvantages of existing codes were discussed. Base upon the results of simulation, the relevant design formula in Code for design of steel structures (GB50017) were modified with the reference of existing foreign codes. And the design methods were proposed for buckling strength and post buckling strength of aluminum plates under in plate bending. It was found that the results of proposed methods were in high accuracy and safer condition, and suitable for the stability design of aluminum plates under in plate bending.     

Beam element end release by extra degree of freedom method

This paper develops a new method of extra degree of freedom (extra DOF) for the beam element with end release. Based on the strain matrix with extra DOFs, it derives the stiffness transformation matrix of released element, which can be applied to situations along global coordinate system or element local coordinate system. The effects of end release processing method for beams with large displacement are analyzed, and the results compared with those from other existing methods show that the extra DOF processing method has higher performance and accuracy.     

Model Analysis of Tower Crane Structure Based on ANSYS

In this paper,a complete dynamic model of the tower crane is set up by the finite element software ANSYS and then the QTZ25 tower crane model is calculated.Through comparing the results,the feasibility of this method is proven.This method is a new approach to fast and precise analysis on dynamical model of tower crane structure.     

人类围垦活动对上海崇明东滩滩涂发育的影响

由于长江口泥沙的淤积,使上海崇明东滩成为一个不断淤涨的土地资源。近50年来,崇明岛共进行了多次大规模的围垦。此项研究以近20年来的Landsat TM和ETM遥感卫星数据为主要数据源,并结合实地景观调查,对不同时期的人类围垦面积和滩涂发育面积之间的关系进行探讨。结果显示,滩涂湿地的面积在逐年变小：从1987年的19705.09 hm2 锐减到2002年的4773.08hm2,减少了75.78%;并且滩涂湿地面积的年减少率为995.47 hm2/a,比年围垦率的729.08hm2/a增加了36.54%。过度围垦后,滩面宽度变窄,自然植被破坏,影响自然促淤,淤涨速率明显减慢。随着滩涂围垦的加剧、未来海平面的上升和河流泥沙大量减少,将会导致潮滩植被进一步破坏。随着崇明东滩每年向外延伸,滩涂湿地也将会发生演替。因此,充分运用“3S技术”,探讨湿地发育和形成的机理,指导科学围垦和土地利用规划,是非常迫切也非常实用的方法。同时,还可以通过动态保护管理,进一步对围垦在经济、生态和环境上的得失作出正确的评价。     

Modal Shape Analysis Methods of Machine Structure

The iterative Lanczos-reduce method for sensitivity analysis, the Guyan condensed method and the iterative synchronous vector methods in finite element modal are studied in order to solve the dynamic characteristic of complicated machine system. The primary reasons influenced on calculation precision are pointed out. The principia of master freedom for Guyan condensed method are put forward. The calculation precision of three methods is compared with the same standard finite element model. The iterative Lanczos-reduce method for sensitivity analysis is proved to be optimum analysis and the eigenvalue of arm in work device of hydraulic excavator in finite element model is solved with iterative Lanczos-reduce method for sensitivity analysis. The theory basis is provided for reasonable choose to solve the dynamic of complicated machine structure.     

渐变刚度钢板弹簧建模方法对比

为更好地分析钢板弹簧刚度特性,对钢板弹簧建模方法进行了对比研究。依据钢板弹簧国家标准GB/T 19844-2005,针对某型渐变刚度钢板弹簧分别在有限元软件Hypermesh和多体动力学软件Adams中建立其有限元模型和离散梁模型,并进行了仿真,得到刚度特性。将仿真结果与试验值进行了比较。结果表明,在针对该钢板弹簧的刚度分析中,运用离散梁法得到的刚度特性更加接近试验值。