Applied Mechanics and Materials Vols. 166-169

Abstract: For the structural optimization of transmission line of steel pipe poles,the structural mass was considered the objective of the economic optimization, the taper of shaft and then the thickness of each wall with the taper of shaft were successively regarded as the design variables, established mathematical modal of transmission line of steel-pipe pole. Various conditions of load calculation were accomplished. Themost unfavorable load condition founded were taken as the design load condition.And LIN-GO is introduced to solve some optimization problems about the design variables. From what has been analysed , it is proved using L INGO on structural optimization of transmission line of steel pipe poles Can significantly reduce the amount of steel used.

Abstract: Based on the general finite-element software ABAQUS, the FE model of 30-story SRC frame-RC core tube hybrid structure is built up. The maximum story drift angle of the structure under cyclic loading can effectively characterize the changes in storey damage. With the new achievements on damage effect factors, the relation between storey damage and component damage of various types and influence of the main design parameters on the storey damage law are analyzed. It is found that storey damage degree is more serious with the increase of stiffness character value and shear wall depth-thickness ratio, but the effects of both of them are gradually weakened and the change range of it is really small. Research will provide theoretical support on the building of hybrid structure damage model under earthquake excitation.

Abstract: In order to apply the uniaxial damage evolution equation that established with the variable of strain to the multiaxial damage quantitative analysis, this paper bases on the Hsieh-Tang-Chen four-parameter failure criterion and adopts the way of making the triaxial equivalent strain combining with the uniaxial damage evolution equation to analyze and deduce the uniaxial damage evolution equation of SRHSHPC, and which is expanded to multiaxial condition as well. A function considered triaxial stress state and a related correction value are suggested, then, improving the damage evolution equation from triaxial to multiaxial form, finally proposing the multiaxial damage statistic constitutive equation for concrete, taking numerical simulation with the complete decoupling method and the result shows that the model is effective.

Abstract: Applying FEM Analysis Software to the analysis that under the conditions of webs with inclinations of 15°，20°，25°，30°，35°，40°, the girders appear mid-span transformation, the concrete stress of the base plate and the stress of the steel webs at the fulcrum. The results of the research show that the increase of the inclination of the web can facilitate the anti-torsion performance of the composite box girders.

Abstract: A macroscopic finite element model and a microscopic one were set up respectively to simulate SRC frame with two bays and three stories under cyclic loading, by comparing the simulation and test results, the authors find that the results obtained from the two finite methods have few differences, and each of them can satisfy the demands of engineering, but the principles established in simulation process were different. The macroscopic finite element model was established by very few elements and the results data were obtained easily and quickly, however, it just attain some macroscopic mechanics data (axial force, bending moment and shearing force etc.). The microscopic finite element model involves complex modeling principle, not only needs more time for dealing with the geometry model, gridding and boundary conditions and so on, but also limited by professional knowledge, which make users establish a correct model hardly. The comparison shows that macroscopic finite element method has many advantages in engineering fields.

Abstract: A new method tracing the load-deflection equilibrium path of a truss with doubly nonlinearity is proposed. The total global stiffness matrix equation has been formulated in terms of nodal coordinates, iteration formulations has been written through adopting a single control coordinate, so that an new method tracing the load-deflection equilibrium path has been proposed. Analysis results of Star dome truss and Schwedeler dome truss have shown that the proposed method is stable numerically, quick in convergence, high in degree of accuracy and easy in use. The proposed method can be used for large-scale truss structure.

Abstract: Elastic-plastic properties of composite materials are an important part of the study on micromechanics. Based on the plastic strain of matrix, the elastic-plastic constitutive model of composite materials is presented in this paper, while considering the influence of the transient flexibility matrix on the flexibility matrix. In comparison with the experimental results, theoretical analysis of the presented model is validated.

Abstract: This paper discusses results of experiments on blind bolted end plate joints to concrete-filled thin-walled steel tubular (CFTST) columns. Four exterior joints to CFTST columns subjected to cyclic loadings. A feature of this novel joint is the use of the blind bolts and extensions to these bolts into the concrete-filled square steel tubular column. Failure modes, moment-rotation hysteretic curves and energy consumption of the connections were analyzed. Further, the connection rigidity and ductility were also elevated by present specifications. The test results showed that the end plate type and the steel tube thickness affect the seismic behaviour of the typed blind bolted end plate joints. The proposed joint has reasonable strength, stiffness and ductility by taking reasonable end plate type, steel tube thickness and blind bolt anchorage; its ultimate connection rotation satisfies the ductility design requirements, and could be reliably and safety used in low-layer or multi-layer composite frames.

Abstract: In the current specification of the pressure ratio limit requirement is not specific, not fully consider the impact of seismic design of frame column ductility of other factors. According to the influencing factors of column ductility analysis, reached standard of axial pressure ratio limit values in most cases are conservative, may be appropriate to do the relaxation adjustment conclusion.

Abstract: This paper describes the results of a furnace test conducted on two-way concrete slab with clamped edges. The details of clamped support condition, arrangement of reinforcement, position of displacement transducers and thermocouple trees are described. Detailed experimental data in the form of describing slab cracking, the temperature distributions within the slab, vertical deflections and horizontal displacements are presented. The experimental results show that the temperature distribution along the slab depth was nonlinear and the temperature gradients in the slab were large. Extensive cracks occurred on the top surface of the slab and formed in an elliptical pattern. It is shown that two-way concrete slab with clamped edges has good fire resistance.