Advanced Materials Research Vols. 243-249

Abstract: Because of saving material, tapered element is widely used in practical engineering. But the calculation of tapered element is very complicated due to its different section forms. By comparing and analyzing the traits and limitations of traditional calculation methods, a new model which is suitable for any tapered element with variable sections was proposed. On the basis of energy method, the model was deduced by a given displacement function. And then through using quadratic polynomial instead of the complex moment of inertia, elastic stiffness matrix of any element with tapered beam member and equivalent nodal load under different kinds of loads were obtained. This method reduces the number of element and degree of free in structure calculation and is relatively simple in theory. The results are compared with two classical examples and ANSYS’s. It shows that the proposed method has good precision in the solution of tapered members.

Abstract: The light-duty steel structure residential demonstration project is analyzed by mode-superposition response spectrum method, the elastic and elastic-plastic time-history analysis, push-over analysis, which used the finite element software ETABS and PKPM. The safety is assessed. The seismic behavior of this structural system is analyzed under different site classification, design characteristic and seismic intensity, and is compared with the ordinary steel structure, concrete structure, masonry structure. The results show that, this structural system can meet the current codes under frequent and rare earthquake action. But the column has a surplus stable stress values. And it is suitable for application in large areas in China. In high intensity areas and compared with the different structure system, it shows that the lateral has the main effect on this structure.

Abstract: The hysteretic performances of steel beam-to-column connections using martensite shape memory alloy (SMA) rods were studied by the experiments. Before the connection test, the material test of Ni-Ti SMA was carried out for the verification of shape memory effect. Meanwhile, the other two type connections (ANGLE and A3) were also tested for comparison. The results showed that connections with SMA rods have excellent energy dissipation capacity, and no strength degradation even subjected to relative rotation of 0.04 rad. It was found that connections with SMA rods possess the higher stiffness and strength than the ANGLE connection, and better ductility than the A3 connection by comparing their hysteretic curves. Large residual deformations of SMA rods can be recovered by application of heat. Retests were performed using heat-straightened rods in the connections, and nearly identical hysteretic behavior was observed as in the case of initial testing.

Abstract: This paper presents a new structural system reliability calculation method with artificial neural network adopt by the sample’s weighting and the artificial neural network, which can greatly reduce calculation work. Firstly, according to the reliability theory of total probability, with the concept of sample’s weighting coefficient, the minimum sample size can be obtained according to the numerical characteristic values of random variables and the minor sample t-distribution estimation under a certain expected value. And then, the optimize artificial neural network is set up with the limited training samples based on the analysis result of sample’s weighting coefficient, which has a highly nonlinear mapping relationship between the efficacy and response of the structural system reliability Analysis. By making use of the generalization capability of optimize artificial neural network, sufficient system response value is gained at random. Meanwhile, the weight coefficients of the random sample combinations are determined using the Bayes formula, and different sample combinations are taken as the input for system analysis. According to one-to-one mapping of system by artificial neural network between the input sample combination and the output coefficient, the reliability index of system can be calculated. At last the method provides a new attempt for S structural system reliability analysis and prove to be feasible and effective for practical experience in complex system, which not only makes the artificial neural network calculation more effective based on sample’s weighting coefficient, also makes full use of the merit of artificial neural network instead of the performance function.

Abstract: In deep water, the dynamic characteristics of bridge piers will be changed. Using the numerical analysis method and the finite element software ANSYS, this paper analyzed the influence of the dynamic characteristics of the pier under different depth of water. At the same time, compared with the analytical method, we found that the results between two methods are consistent. But to the complex structure, the numerical analysis method would be superior.

Abstract: The cold-formed thin-walled tube has been widely applied in high seismic fortification intensity region and post-seismic reconstruction area because of light quality, high strength and small deformation. But the connection mode and mechanical properties of beam-column connections still need further study. According to the "strong column and weak beam" seismic design principle and the thinking of control the position of plastic hinge, adding haunch slabs at the end of beam to reduce the number of repeated welding and avoid brittle fracture. Through the low cyclic loading experiment, four beam-column connections with welded haunch under different axial compression ratios have been studied, and connection’s hysteretic performance, energy-dissipating capacity, bearing capacity, rigidity and failure mode have been discussed. The result shows that: 1) the ultimate bearing capacity of connection with welded haunch is much great, and the energy dissipation capacity is very well, which can make this connection to absorb and consume great energy in earthquake. This connection can meet the need of seismic design very well. 2) The connection with welded haunch experiences much cycling time, has long yield platform after yield, has great cumulative energy-dissipating capacity and well ductility. 3) the final destruction of connection with welded haunch is caused by the beam’s local buckling. And the yield surface is almost located at the outside of connections. 4) The axial compression ratios has great effect on the hysteretic performance, bearing capacity and stiffness degradation for the connection with welded haunch.

Abstract: The triangular plate has widely application in the manipulation of the pr angular plate will often have error. In the former solutions, it is very hard to find one kind of simple and common way to solve the equation of deflection curve of the triangular plate. Under uniform load function, this paper uses the reciprocal theorem method to discuss the bending question of triangular plate with the unfixed hypotenuse and fixed side as well as the other side with simple supported, and the unfixed hypotenuse as well as two fixed sides. Thus the method has overcome complicated calculating process appeared in the classical theory, solved the limitations with difficulties to certain questions and established new way to solved the bending question of triangular plate. In the process of calculating, it will take specific proportion, applying the mixed variables method, carrying the calculation on the Matlab platform, and comparing it with the ANSYS finite element analysis result, to prove the result is correct. Thus the paper gives the equation of deflection curve and the graphs which can be employed in the actual project application. Therefore, the paper has certain theoretical value and project significance.

Abstract: In order to compare the initial and improved Hertz-damp model, the dynamic equations of collision system were established based on Hertz-damp model and mode superposition method. Hertz-damp model can account for the influence of the nonlinear contact stiffness as well as the energy loss during structural pounding. The results analysis show that the initial model have the same simulation results with the improved model initial model when the restitution coefficient or the contact stiffness large enough. For typical concrete structural pounding, the initial model is available.

Abstract: Based on the fact that building material strength degeneration rules in domestic and overseas are different under the high-temperature fire, with the program ANSYS, the temperature stress distribution of cross-section is obtained and the two results are compared according to stress analysis of numerical simulation on the axial compression steel reinforced concrete column (ACSRCC) under high-temperature fire. Based on the conversion principle of different materials stress and the superposition principle, the numerical calculation method on cross-section stress of ACSRCC under high-temperature fire is proposed, and the calculated results agree with simulation data well. The influences of the concrete coverage thickness and other factors on ACSRCC mechanical properties under high-temperature fire are also discussed in the paper.

Abstract: "cadre design of the foundation ",which is up to the national standard of the People's Republic of China , gives the principle of cadre design of reinforced concrete. With the principle of the standardized structure design given in the literature, the specific calculative formula is deduced. During the formula deduction process, there exits some obvious conceptual errors, which lead to problems in the calculation formula of the design of foundation structure. Analysis the problems in design of reinforced concrete of below-wall strip foundation and under-columniation independent foundation, point out the cause of the problems and detrude the accurate calculative methods of these cadre design. Via the calculative examples, compare the difference of calculative results and the results of original method, prove that the accurate calculative methods are consist with the theory analysis.