Applied Mechanics and Materials Vols. 405-408

Abstract: The article considers the influence of neutron flux on the reactor hemispherical shell protection, depending on time. Diagrams of the variations of modulus of elasticity, of strain and stress appearing during the operation of the nuclear power plant are given.

Abstract: Wind energy industry has been growing tremendously in recent years. Tubular steel towers are currently dominant supporting structures for wind turbines. With the increase of the converter capacity, there is a great demand for higher supporting towers. However, structural vibrations in extreme wind events tend to become a major concern during tower design. To study wind turbine tower dynamics, an existing tubular steel tower was tested. Vibrational frequencies and damping ratios were identified. To avoid unexpected dynamic problems, a space frame steel tower has been proposed for supporting larger wind turbines. It is a structural system that can be assembled on-site by using prefabricated beams, columns, and brace members. A typical space frame steel tower was designed in this paper. Static loading, modal and buckling analyses of the tower were presented. It is expected to introduce engineers and designers more options for wind turbine tower design.

Abstract: By the method of ANSYS finite element analysis, this paper in depth studies the affection of widened width and length of the widened beam flange joints on seismic behavior of the ultimate load and ductility performance. According to the test and failure results of finite element simulation specimen the cracking possibility of the weak link easily leading to fracture of joints is evaluated. By introducing the equivalent plastic strain index, the fracture mechanism of widened beam flange joints is analyzed theoretically. The research can provide valuable data and reference for the seismic design of steel frame joints.

Abstract: As for the study on the development regularity of slab concrete cracks under the fatigue loads with amplitude of certain values, two groups of reinforced concrete slab bridge specimen were made. The fatigue test was carried out on one group of specimen, and the corresponding static load test was carried out on another group of specimen, the experimental study on the development regularity of concrete cracks at bottom of slab were carried out. The results of the study shown that, under the fatigue loads at a certain amplitude, the development trend of cracks caused by loading at the bottom of slabs changed more under fatigue loads. The reasons caused the changes of development regularity of concrete cracks were analyzed. The experimental results has the vital significance of further research on the development regularity of concrete bridges under the action of fatigue loads.

Abstract: The paper analyzes the basic theory of prestressed concrete cable-beam structure in single span and single direction.The paper arranges reasonably the shape of cable,deduces the equation of cable. It introduces the reseach status and the importance of stability and demonstrates the basic relative theory on stability in concretely research and applies this theory on prestressed concrete cable-beam structure. It has significant prospect and is easy to put into practice .

Abstract: This paper established the theoretical equations of transfer matrix method for shear wall structures with large space at lower part to calculate natural vibration periods. The bottom structure is simplified as a hinged plane system with a complex frame and a complex shear wall, and the upper structure is simplified as a complex shear wall. Transfer matrixes between adjacent stories were established according to the fluctuated equations of complex members and equilibrium and displacement compatibility conditions. After multiplying the transfer matrix of every story, transfer matrix of the whole structure was established. Finally, the solving equation for the natural period was deduced by the boundary conditions. An example showed the feasibility and reliability of the method. In comparison with FEM, it is a convenient and universal method and is recommended for preliminary design of shear wall structures with large space at lower part.

Abstract: In this paper, the behavior of concrete-filled double skin steel tubes (CFDST) with simply supported boundary condition was analyzed by Finite Element Analysis method. The Finite Element analysis mode was established and the results have a good consistent with experimental results. The work mechanic and full range analysis of concrete filled double steel tube under lateral impact were analyzed, the results show that the damage of CFDST with simply supported boundary condition under lateral impact is in ductile manner.

Abstract: By introducing the basic concepts and designing principles of special-shaped column structure, this paper attempts to establish three finite element models (the special-shaped column structure, rectangular column structure with the equal area and rectangular column structure with the moment of inertia) by using the SAP2000. And the basic dynamic structure properties of three structures are analyzed. It’s base of the dynamic analysis for the structure. Then, the paper analyzes the elastic seismic performance under the horizontal earthquake action by using the vibration spectrum method and the elastic time-history analysis method. The results show that three models are all in the elastic steps. We compared the anti-seismic property of three models under frequent earthquake.

Abstract: This paper discusses the development of acoustic emission tomography to identify structural discontinuities in concrete. An algorithm was developed to reconstruct velocity tomographs of the interior of the material. Both theoretical analysis and experimental data were used to determine best sensor array geometry. Experiments on a concrete block with artificial fracture indicate that the technique can be used to identify structural discontinuities.

Abstract: This paper uses the finite element analysis software Ansys to model a tall building structure in three-dimensions, then analyze the modal and the response of the structure under wind and earthquake. It provides some references to the dynamic analysis of tall building structure.