Sensitivity analysis and lightweight design for the frame of all-terrain vehicles

In order to decrease the manufacture cost of all-terrain vehicles rapidly and effectively,a finite element model for the frame structure of all-terrain vehicles is built by using pre-processing software HyperMesh. The correctness of the model is verified by computing the freedom mode of all-terrain vehicles with Optisturct solver and contrasting it with existing test results. Through applying Optistruct solver and Fatigue to analyze stress distribution,deform and fatigue life of the frame under multi-conditions,and combining with sensitivity analysis results,the lightweight project of the frame is put forward. The validity of this lightweight project is identified after analyzing the optimized frame structure intensity and the fatigue life. The lightweight result show that the frame structure is lightened 6.6063 kg. At the same time,it shows that the structure optimization efficiency and the lightweight effect are enhanced by sensitivity analysis.     

Research on Deformation Equation and Dynamic Properties of Hybrid Structure

Based on the principle of interactive analysis,the deformation equation of hybrid structure which contains rigid character value is established using the analysis of the frame - shear wall structure for reference, considering the rigid zone between concrete beam and concrete - tube, the shear deformation of concrete - tube, axial deformation of steel frames and semi - rigid connection between steel columns and concrete beams. Assuming the hybrid structure to be a continuous elastic structure with infinite degree of freedom, a free vibration equation has been built and the formula for calculating free vibration period has been deduced. The influences of various parameters to the coefficient of free vibration period relating to rigid character value are discussed according to some diagrams. It is shown that the rigid zone can lessen the free vibration period but the shear deformation of concrete - tube, axial deformation of steel frames, and the semi -rigid connection between steel columns and concrete beams can enhance the free vibration period.     

Curvature Force Method for Nonlinear Analysis of Prestressed Concrete Frame

In this paper, based on the structure characters and load applying means, a method called as curvature force method is put forward and proved in the nonlinear analysis of bonded prestressed concrete frame. Based on the nonlinear program, the simulation calculation was carried out on test results of two prestressed concrete frames by this method. The results from calculation are identical with the experiment ones. So it may be added to the methods for the nonlinear analysis of prestressed concrete frame.     

Nonlinear Analysis Technique of Refined Plastic-hinge Method for Steel Frame Structures

The refined plastic-hinge method is one of the simplified advanced analysis methods. The second order effects of the whole structure and its members, geometric imperfections and residual stress as well as the feature of semi-rigid connections can be taken into account in this method. The refined plastic-hinge method can be used in advanced analysis and design of planar steel frames, while its use in the advanced analysis of space frames needs to be developed. The technique associated with the dealing of different inelastic factors in advanced analysis of both the planar and space steel frames with practical refined plastic-hinge method and the available way to extend planar frame analysis to space frame analysis are reviewed in detail. The problems of the refined plastic-hinge method for advanced analysis are discussed in this paper.     

新型农业大棚骨架的性能分析

旨在研究复合材料光伏农业大棚的经济性和受力性能,阐明其替代钢结构大棚的可行性。运用有限元软件Midas对某光伏大棚骨架的受力性能进行分析;对光伏大棚最不利节点螺栓的承载力验算;从表面维护和骨架用材两方面进行经济性分析。结果表明:复合材料骨架大棚的杆件最大应力为27.5 k Pa,其柱顶最大位移为9.4 mm,满足相似结构的承载力和容许位移要求;最不利节点螺栓的承载力计算结果表明节点强度足够;从每栋复合材料大棚和钢结构大棚的骨架表面维护及用材两方面的经济性分析结果看,前者初期费用较后者多300元,但使用过程中不再需要追加维护费。从可持续发展的角度看,采用相同骨架的2种材料成本投入相差不大,复合材料更具有环保特点,对农业养殖或种植无不利影响。可以推断,只要结构布置合理,复合材料骨架大棚承载能力绝不输于钢骨架大棚。     

Seismic Tests and Pushover Analysis of Spatial RC Frame-Shear Wall Structures

Pseudo-static tests of three one-storey spatial RC frame-shear wall structures with floor slabs were conducted to investigate their failure modes and hysteretic behaviors. The test results were compared with those of pushover analysis. It is shown that: 1) damage of the frame beams occurs later and is less than that of the shear wall and the frame columns; 2) damage of the floor slabs under lateral loading is significant in regions close to the shear wall, and tensile stresses of slabs' steel bars in these regions are much larger; 3) in comparison with the case that the floor slabs are neglected, the maximum lateral load that a frame-shear wall structure can bear is larger in the case that the floor slabs are taken into account, and the contribution ratio of the shear wall also increases; 4) shear forces carried by the frame columns with identical cross sections and reinforcement details but located at different positions are close to each other on the whole.     

Deformation Analysis of Thermo Elastic Plastic on ReinforcedConcrete Structure Subjected to Fire

To investigate the mechanical behavior of reinforced concrete structure subjected to fire, the incremental thermo elastic plastic creep constitutive equations of steel and concrete in consideration of temperature and creep deformation were obtained based on different yield rules and the elastic plastic theories. The nonlinear analysis for reinforced concrete simply supported slab was carried out with consideration the variation of the mechanical properties of steel and concrete with temperature. The effectiveness and applicability of the constitutive equations were verified with the test results from relevant literature. The nonlinear analysis was employed for one bay one storey reinforced concrete frame under fire and the variation of displacement at partial nodes was analysed. It was found that the reinforced concrete structure at a high temperature would have a significant deformation. And the displacement change curves of beam column joints of reinforced concrete frame were not monotonous trend and there were inflexion points. The vertical displacement values of beam column joints were less than those at midspan of cross beam.     

A forward algorithm for prestressed construction process of large-span suspendome based on the equivalent pre-tension

To accurately simulate prestressed construction process of large-span suspendome, the initial state of construction process according to practical construction sequence is established, and the construction mechanical analysis for prestressed construction process is especially studied. Features of prestressed construction process of large-span suspendome are summarized, and the insufficiencies of the application of state variable superposition method, back analysis method, birth and death element method are analyzed. Combined with nonlinear finite element analysis method, forward algorithm for prestressed construction process based on the equivalent pre-tension is proposed, and the specific application method and procedure are given. Changzhou stadium steel roof engineering is taken as an example to verify the practicability and applicability of forward algorithm for prestressed construction process. The conclusion is that, using forward algorithm for prestressed construction process based on the equivalent pre-tension, the structure state of each construction phase can be accurately tracked, and the nonlinear contact of strut and rigid framework, interactive impact of cable force, conversion of temporary structure system, and structural geometric nonlinearity can be comprehensively considered.     

EFFECT OF SEMI-RIGID CONNECTIONS ON BEHAVIOR OF STEEL FRAME

Modeling of girder in steel frame with semi-rigid conn-ections as partially restrained beam element is proposed for elastic-plasticanalysis of steel frames with semi-rigid connections.The results whichare obtained from analyses of elasticity,plasticity and stability for steelframes with semi-rigid connections have significant effects on structuralbehavior.It is necessary to consider the influences of semi-rigid conn-ections on the analysis and design for steel frames.     

BEHAVIOR OF THE REINFORCED CONCRETE FRAME CORNER JOINTS SUBJECTED TO CLOSING LOADS

In this paper, experimental results on the tests of 15 full-scale reinforces concrete frame corner joints subjected to closing loads arereported. The primary variables are the compressive strength of eoncrete, thesteel ratio and the ratius of main bar bend. In order to investigate the stressdistributiens of the concrete in the cores of the joints, a nonlinear finiteelement analysis of the frame corner jonts is carried out. Possible damage andfailure modes of the frame corner joints are discussed herein. Based on observedand computed results, the formulae in terms of the steel ratio and the ratius ofmain bar bend and the corresponding useful recommendations are made for thedesign of the frame corner joints.     

Composite Steel- concrete Frame Beam with Reinforced Negative Bending Regions

Considering the large negative bending moment at the end of frame beam and low tensile strength of concrete,a new composite steel-concrete frame beam(CSCFB),reinforced by a T shape steel beam at the negative bending regions,was brought forward.Through two full-scale of single-layer CSCFB frame models experiment,the load-displacement curves of CSCFB and strain distribution at cross section were obtained.Compared with the ordinary composite beam,the T shape reinforcing section can enhance the beam stiffness effectively,and make it distribute reasonably.The segment flexural rigidity method is presented and validated.     

Experimental Investigation of Steel Frames with Infill Prefabricated Reinforce-Concrete Shear Walls

In order to improve seismic performance of steel frame with prefabricated reinforce-concrete infill shear walls (SFCW), the ear bar device was used in the connection between the steel frame and the infill wall. Two one-bay, two story and one-third scaled models of SFCW were tested with low cyclic load. The working performance of ear bar connection, the cracks development in infill walls and deformation performance of SFCW were investigated. And the failure mode, hysteretic behavior,stiffness degradation,deformation and ductility and energy dissipation of composite structure were analyzed. The comparison study of steel frame with prefabricated, cast-in-place and silt reinforce-concrete infill shear walls was carried out. The results show that no failure occurs in the connection between the steel frame and the infill wall because ear plates below and up the beam-to-column connections are added in the specimens, and the connection device of ear plate presents good working performance. The properly designed SFCW has good ductility.     

Finite Element Analysis of Hysteretic Behavior of PR Steel Frame-steel Plate Shear Wall

In order to investigate the seismic behavior of partially-restrained steel plate shear wall (Steel Plate Shear Wall, SPSW), the effects of partially-restrained connection on the hysteretic behavior, lateral bearing capacity, stiffness, energy dissipation of SPSW with strong and weak steel frame were simulated under low cyclic loading via equivalent strip model that had been verified by experiment. The results show that hysteretic behavior of SPSW has dual characters. The hysteretic curves of SPSW with strong surrounding steel frame become fat, and the hysteretic curves of SPSW with weak surrounding steel frame become narrow. With the increase of the bending capacity of PR connection, the hysteretic curves of SPSW become fat gradually, and the capacity of energy dissipation and lateral bearing increase. However, the effect on lateral stiffness of PR connection of SPSW with strong steel frame is higher than the one with weak steel frame.     

A PRACTICAL METHOD FOR SELECTING STEEL USING COMPUTER AIDED DESIGN(CAD)SYSTEM FOR REINFORCED CONCRETE FRAME

How to select automatically the disposition of steel bar in a computer aided design(CAD)system for reinforced concrete frame structure is aproblem relatedt ot he practicality and increasing capacity of the CAD system.This paper suggests a practical method for selecting steel bar of beam in framestructure with the application of knowledge and experience of the experts forreasoning and judging.The method is convenient for calculation.The results ofcalculation are in agreement with detailing requirement and usual engineeringpractice.The method has great practical value.     

A Study on the Effect of Horizontal Strengthened Story to Super High- rise Steel Braced Frame

The Effect of horizontal strengthened story to the seismic response of super high - rise steel braced frame is analyzed in this paper through the finite element software ANSYS. By comparison of six different schemes of a 32 - story building, further research is presented on the influence of the quantity of strengthened story to the lateral stiffness, the inner force of components under earthquake and the distribution of shear force among inner tube and outer frame. According to the study, the Wuhan International Securities Mansion, which is a super high -rise steel structure, is described as verification. The response of the building is analyzed in small earthquake. The study can serve as the references of super high - rise structure with horizontal strengthened story design.     

Hysteretic Behavior of Composite Deep Beam Infilled Steel Frame

The Quasi static tests of one steel frame and two the composite deep beams infilled steel frames were carried out. The effects of the deep beams on the load capacity, ductility, hysteretic property and energy dissipation of pure steel structure were analyzed. It is found that the hysteresis curve is a straight line with the constant of the stiffness at the beginning and without residual deformation. And the hysteresis curve of specimen was full after yielding, and the skeleton curves had a clear plastic flow phase with triple linear. The lateral drifts of the beam specimens at failure were 1/25 and 1/22. The composite deep beams enhance the initial stiffness, yield load and maximum load bearing capacity of steel frame. Therefore, seismic performance of the composite deep beams is better.     

Simplified Elasto Plastic Analytical Model for Stiffened Steel Plate Shear Wall with Slits

Based on the mechanism of steel slit wall, a simplified elasto plastic analytical model which allows for nonlinear dynamic and static analysis was proposed. The parameters of simplified model related to configuration and nonlinear behavior were defined. In order to validate the simplified model, the pushover analysis of steel slit wall and a frame with steel slit wall were conducted. The results show that the load displacement curves obtained from simplified models, experiments and FEM are similar. The proposed model can fully represent the mechanism of steel slit wall, and it can correctly predict the internal forces and deformations of each member in the model.     

Capacity Design Measure in Seismic Design of RC Mega-Frame Structures

It provides several typical mega plane frame designs on condition that the variables are the combination of varying amplification factors of moment at bottom sections of ground floor columns of the minor frame on the major beams. The elastic-plastic dynamic analysis program Drain-2d+ of the plane structure is used to get elastic-plastic time-history analysis for each typical mega frame under the action of seism. The autuors obtain the information of the mechanical transmutation characteristics, the emergency of the plastic hinge and the weak point of the whole structure under the action of seism, from which the correct thinking of how to obtain the design value of amplification factors of moments at bottom sections of ground floor columns of the minor frame on the major beams is found. The reasonable design values are recommended in order to provide some suggestions for the design of the reinforced concrete mega-frame structure.     

Study on Equivalent Frame Model for Large-span Prestressed Concrete Residential Structure System

In this paper, a study is carried out on large-span prestressed concrete structure system in residence analyzed by specially - shape column equivalent frame model. Applying fiber model column-beam element and shell element, a large amount of comparative analyses about large-span prestressd concrete structure under horizontal and vertical load is carried out. The parameter of the equivalent frame is confirmed based on comparison with the result of the man-sized structural experiment. It is proved that the equivalent frame model has high efficiency and precision especially for nonlinear analysis.     

Finite Element Analysis of the Influence of Steel Strength on Beam-to-column Composite Connections

Because high material strength and composite load-bearing are emphasized in constructing members for high-rise steel frame structures, in a composite connection, steel strength has a dramatic influence on both the bearing performance and the composite action of the concrete slab. Based on a finite element analysis, we discuss the composite effect and the connection breaking mode, focusing on the performance change of the composite effect in adopting high strength steel. It can be found from the results that, along with the improvement of the steel strength, the elastic and plastic ultimate strength of the composite connection will increase, the ductility will decrease to a certain extent, and the composite effect of the concrete slab will diminish. The collapse of the concrete in a positive moment side contacting the column flange is viewed as the limiting state of the connection.