Applied Mechanics and Materials Vols. 94-96

Abstract: A finite element method was developed to reveal the thermal characteristics of concrete with a cooling pipe, and the influence of cooling pipe on thermal field was calculated by the coupled fluid flow and solid heat transfer method. Temperature distribution along the pipeline was calculated and the mean Nusselt numbers on each section in the cooling pipe also were obtained. Numerical results show that the flow field and the temperature distribution were very complexly and the heat transfer was severely attenuated in the bend position, the outboard temperature of pipe was higher than the inboard temperature. In addition, in order to study the effect of the cooling pipe on thermal distribution, the temperature of different positions at the hydration time were compared with the no cooling results. The present results could be helpful to predict the temperature cracks in structure engineering.

Abstract: With the increase of the height, the lateral stiffness of high-rise buildings decreased. The high and flexible structures would have large movement when they are suffered lateral forces arising from earthquakes and winds. In order to investigate the influence mechanisms on dynamic behaviors of three-towers-connected high-rise building that caused by connection stiffness, various finite element models with different connection location and number are established and the dynamic properties are analyzed by finite element software ADINA. The results show that the influences of connection stiffness on structural natural cycle are obvious, and the impacts on displacement and acceleration response are minor.

Abstract: Concrete is a typical kind of rate sensitive material. In this paper, the concrete specimens were tested in the SHPB experiment system. Based on H-J-C constitutive model, the SHPB experiment was simulated by LS-DANY. The stress-strain curves which were gat from numerical simulation in the LS-DANY were compared with the stress-strain curves which were gat from SHPB. The results showed that the H-J-C constitutive could simulate the dynamic characteristics of concrete both under room temperature. The result also showed that the concrete was strain rate sensitive. Based on the numerical simulation, the stress wave in the SHPB system was studied. The research of the numerical simulation showed that the stress waves tended to become stable after several oscillations in the incident bar. At the same time, stress wave of elements in r=0 (The distance of elements to the axis was 0) were bigger than the stress wave of r=0.5R (The distance to the axis was 0.5R) and r=R (The distance to the axis was R).

Abstract: The structure of eccentric degenerated 3-D shell element of thin-wall steel tube concrete composite structure and the connection with 3-D block isoparametric element has been discussed using finite element method. Without considering the intensity limit of delamination damage of the two materials, an integrated stiffness matrix is formed with the combination of stiffness matrix of steel-wall shell element and that of concrete spatial block element. In order to make the superposition rule may be used at the joint of 8-node curved shell element and 20-node block element, an eccentric 8-node shell element is constructed.

Abstract: Abstract: Confined masonry with tie columns and ring-beams was adopted during the reconstruction in the rural and suburban areas in Sichuan Province after the 2008 Wenchuan Earthquake. Based on the results of the sample tests of building material such as clay brick, cement mortar, steel and concrete in reconstruction and the analysis on the characteristics and features using Solid65 elements in ANSYS, the shear property of joints in masonry structures under different vertical load (σ∕fm) is numerically simulated. Comparing the experimental results with the numerical ones, the proposed values for the shear transfer coefficients for open and closed crack of Solid65 elements for simulating masonry structures are given. The seismic performance of confined masonry walls (strengthened by tie column and ring-beam, etc.) and unconfined masonry walls with different stress condition (σ∕fm) under low cyclic load are discussed. Results show that, under monotonic loading, confined masonry walls have better performance for displacement and load corresponding to the occurrence of the first crack as well as for the ultimate load and ductility, although the energy dissipating ability of unconfined walls under low cyclic loading increases with vertical load (σ∕fm) at low stress level. The results demonstrate that confined walls are greatly enhanced by strengthening measures such as tie column and ring-beams.

Abstract: Many heterotypic steel frames with special-shaped are used in the concert of Changsha. It causes difficulties to the construction technology. Based on the characteristic, It is studied the construction process, then put forward the subsection lifting technique, applied energy analysis method for lifting point and used finite element analysis for supporting system. At the same time, it is used measuring robot 3d positioning method and elaborated the operation points, At last, it is analyzed the welding technology. All of these provide guarantee to the smooth construction.

Abstract: Nonlinear buckling analysis method using the finite element with application to Long-Span Steel Truss was studied is this paper. The finite element model of long-span complex steel truss hoisting was established and nonlinear buckling analysis of long-span complex steel truss hoisting for two hoisting points schemes was accomplished. The eigenvalues, eigenvalue buckling modes and nonlinear buckling analysis of two hoisting point’s scheme were analyzed. The results indicate that, the nonlinear buckling analysis method using the finite element is applicable approach to study the hoisting buckling problem, the buckling will be not occurring under hoisting stage only with gravity loads. The force status of long-span complex steel truss is improved under more hoisting point’s scheme and the lateral stability is strengthened.

Abstract: This paper presents an investigation of ultimate strength of square CFT stub columns with compact sections. The beneficial composite action between the steel tube and the filled concrete is taken into account and a new analytical model for predicting the axial capacity of square CFT stub columns with compact sections is proposed. Experimental results of 89 axially loaded square CFT stub columns published in the literature are then used to verify the proposed strength model. Results show that the proposed strength model provides a direct, compact, and efficient representation of the ultimate strength of square CFT stub columns made with not only normal strength but also with high strength steel tubes and concrete.

Abstract: Based on a prototype of a Concrete Filled Steel Tubular(CFST) column (D=1.2m, t=24mm) used in a practical engineering, specimens length-diameter ratio of which is 3:1 are designed to conduct the uniaxial compression experiment according to three scales which are 1:2.4, 1:3.6 and 1:4.8. FE model is established to simulate the loading process by means of finite element software ABAQUS. The study shows that the bearing capacity of test is much higher than the value calculated according to codes. It’s about 7% higher than the design bearing capacity calculated according to code CECE28:90. The outer steel tubes of CFST columns used in engineering are generally processed by wrapping and welding. The welding zone is easily to yield firstly when the CFST columns are under uniaxial compression, which can change the compression bearing state of the cross section to bias compression. As a result, the bearing capacity of the CFST columns would decrease to some extend.

Abstract: Flexural-torsional buckling of the beam in steel frame with reduced beam section (RBS) connections is analyzed. Base on the analysis of flexural-torsional buckling of the RBS beam under different loads using energy method, the critical moment calculation formula of ordinary beam is modified, and the critical moment calculation formula of RBS beam is presented. Moreover law of the RBS beam critical moment varying with cut sizes and location is discussed when compared to the critical moment of the uniform beam. The results show that: reduction has great effect on flexural-torsional buckling of RBS beam, critical moment of the RBS beam obviously decreases as compared with ordinary uniform beam, but single cut parameter has small effect on changes in critical moment; the effect of reduction on beam stiffness decreases as beam span increases.