Advanced Materials Research Vols. 594-597

Abstract: Building a whole vessel model ,and make use of FLUENT to calculate the resistance and surface pressure of the vessel in a certain speed . Compile a user-defined function, in which the numerical wave channel has been developed, thus the surface pressure was calculated in two kinds of special conditions, hogging and sagging, and then by using of the Fluid-solid coupling method, the surface pressure was exported to ANSYS.The method uses a same hull model in the flow field and the structure calculation process, avoiding the loss and distortion of information in the previous model transformation , and the calculated results can analyze more accurately the stress and deformation of the hull. The results for performance assessment of the vessel are effective and the calculation method can be a reference in the structure optimization design of vessels.

Abstract: It is well known that research on mechanical characteristics of the underground draft tube and corresponding stress distribution of the steel lining under complex conditions plays an important role on assessing the underground powerhouse and hydropower project safety. However, due to complex boundaries and load conditions of the draft tube, especially the concrete itself is so easy to crack, crush and become plastic that it is more difficult to determine its 3-Dimensional mechanical behavior of the underground draft tube. To better solve the above difficulties, 3-D FEM simulated model was built based on the universal software named Ansys to analyze the stress distribution of the draft tube structure and the steel lining. The calculation results showed that the hoop stress and radial stress of the tube were all satisfied with the standard requirement, and maximum stress of the steel lining also accorded with the strength requirement, which indicated that simulation model and the analysis method brought forward in the paper was applicable and practical, and also provided an effectie method for the underground structures design and steel arrangement of the draft tube.

Abstract: This papers deals with the study of the influence of prestress force on the natural frequencies for unbonded prestressed concrete beams. A total of 5 unbounded prestressed concrete simply support beams were constructed and tested. The test results show that the prestress force has little effect on the nature frequencies of unbonded prestressed concrete beams. A model of variable stiffness is proposed to calculate the natural frequencies of prestressed concrete beams with unbonded tendons, which assumed that the flexural rigidity of the beam is changing when beams vibrating. The calculate results show that the calculation results by the proposed model agree well with experimental ones.

Abstract: Abstract. In the paper, take full account of energy dissipation operating characteristics. Interlayer shear-frame structure for the analysis of the Wilson-Θmethod ELASTOPLASTIC schedule, the design of a nonlinear dynamic time history analysis procedure. On this basis, taking into account the restoring force characteristics of the energy dissipation system, the inflection point in the restoring force model treatment, to avoid a result of the calculation results of distortion due to the iterative error. A frame structure seismic response time history analysis results show that: the framework of the energy dissipation significantly lower than the seismic response of the common framework, and its role in the earthquake when more significant.

Abstract: Base on the achievement and research on the concrete filled steel tube (CFST), with 4 aspects: research on fundamental structural behavior, dynamic property, bonding theory of interface and research on the concrete filled square steel tube, summarize the findings about CFST and introduce the 4 stages of development of study of CFST. Point out that the research on the bond theory of interface between steel tube and core concrete and the concrete filled square steel tube are needed the further study and research.

Abstract: The static element in static deformation analysis was used to simulate the boundary condition of local structure when studying the modality of local structure. Using this method, the vibration modality of a beam system and the main engine lubricating oil tank were researched. The results show that the usage of static element in dynamic analysis can solve the vibration modality of local structure accurately, the difference ratio of first order frequency is less than 1/10000 in the beam model analysis, and the modal analysis of main engine lubrication oil tank has a good performance, which is a helpful base for the coupling vibration research in ship structure.

Abstract: In China as the overhead transmission line corridor is less and less, multi-circuit transmission line tower application would become more common. In this paper the multi-circuit tower type design problem was analyzed and discussed, and put forward some ideas on how to solve these problems. To 330kV four-circuit tower type design as an example, the design steps, methods were described in detail, and gave three kinds of design schemes, finally, three kinds of tower characteristics are analyzed to draw valuable conclusions.

Abstract: The finite element formulations of steel-concrete composite (SCC) beams considering interlayer slip with end shear restraint were established. Free vibrations of SCC beams and frame structures under different slip boundary conditions were examined. The influences of the shear connection stiffness and the slip boundary condition on dynamic characteristics were analyzed. It is shown that the low order 8-DOF element may exhibit slip locking phenomenon in free vibration analysis for very stiff connection. The free vibration frequencies of composite beams and frame structures increase with the shear connection stiffness increasing. Besides, it is found that the natural vibration properties of SCC frame structures are significantly affected by the slip boundary condition, and it should be suitably imposed on all composite beams in dynamic analysis.

Abstract: The project intends to construct steel pipe piles on both sides of trestle wharf, and the soil vibrations caused by piling construction might have an important effect on the safe service of wharf. In this paper, the dynamic signals during piling construction were recorded and recognized by NExT-ERA. Meanwhile, modal analysis through finite element model of wharf was performed. Through a comparative analysis of the two results, the first two orders of frequency for wharf were obtained. The results would lay foundation for further analysis of dynamic responses of wharf when pile locations close to wharf.

Abstract: Wooden buildings which has a long history, is one of the earliest forms of building structures by mankind.The structure form and construction method of are different from the common prestressed structure,therefore,the prestressing loss caused by the external prestressed structures is different from that of the common prestressed structure.It is an effective method to reduce the large deflection of large-span wooden structure by external prestress method.Through the real model test of the external prestress tension at scale of 1:2,and after long-term observing on parabolic wooden beam of external prestress with initial pretension force,we can quantitatively analyse the effections of prestressing loss of prestressed rebar due to the creep of wood.At the same time,this paper gives the deflection calculation formula during the term of test.The conclusion obtained is useful to designers.