Advanced Materials Research Vols. 255-260

Abstract: Applicability of the simplified method based on equivalent single-degree-of-freedom (ESDOF) for single-column pier with uniform cross-section is investigated in this paper. The modal participating mass ratio of pier’s fundamental mode is taken as an index to evaluate the applicability of the simplified method. Based on the fundamental mode shape functions selected deliberately in the first step, equations to evaluate the modal participating mass ratio of pier fundamental mode is obtained. Using the proposed equations, it is convenient to evaluate applicability of the simplified method with the height of the pier and the ratio of the linear mass along the column to the dumped mass at the top of the pier. Finally, the index is verified in the different nonlinear range of piers.

Abstract: The dynamic characteristic as one key feature determines the earthquake response and seismic performance of structures.Curved box beams occur coupling of flexural and torsional modes,which companied with warping.Based on the precise transfer matrix method,precise transfer matrixs for solving the natural frequencies and modes of curved box beam out plane have been derivated.The analysis of vibration characteristics of single-span curved box beam with pinned-pinned ends has been done. Example shows that the precise transfer matrix method is a simple and effective method for dynamic characteristic analysis of curved box beams.

Abstract: Blast-induced seismic wave, which is an instantaneous, complicated wave, is different from natural seismic wave. It has characteristics such as high frequency, fast vibration intensity attenuation rate with distance increasing, short duration, generally small hypocenter energy and short wavelength of blast-induced seismic wave, etc. In this paper, on the basis of motion equation of the structural system and through rigorous mathematical induction under blast-induced seismic action, the energy transfer (input) and transformation equations of single freedom structural system and multiple freedom structural system are obtained and carefully studied. Through using stress-strain connection and the transmission characteristics of wave in different medium, the author explored the mechanism and time-space process of the action blast-induced seismic vibration has on structure. Meanwhile, the author also analyzed the impacts blast-induced seismic vibration characteristics and structure dynamic characteristics have on structural reaction. Furthermore, the mechanism of action blast-induced seismic vibration has on structure is revealed.

Abstract: This paper reviewed the research on the vibration of orthotropic circular membrane. We applied the large deflection theory of membrane and principle of virtual displacement to derive the governing vibration equations of circular membrane, solved it, and obtained the power series formula of nonlinear vibration frequency of circular membrane with all edges fixed. The paper gave the computational example and compared the frequency with different initial displacements, respectively. Results obtained from this paper provide some theoretical foundation for the research of orthotropic composite materials; meanwhile, the results provide some theoretical foundation for the research of nonlinear vibration of membrane.

Abstract: Track irregularity is one of the most important factors that induce vehicle-track-bridge coupling vibration. In this paper, spatial model of vehicle- track-bridge system is established. The track irregularity sample in time domain are established by power spectrum density and taken as the exciting source to analyze the spatial coupling vibration of vehicle-track-bridge system. By comparing the vibration responses of the model excited by vertical profile irregularity and the model excited by four different irregularities, the change of track irregularities have mostly influence on the vibration of the parts above the rail and nearly no influence on the parts under the rail and bridge.

Abstract: This paper is based on the two model demonstrative project of science and technology of Changsha-Xiangtan highway which are non-navigable piers, which belong to a new extra large bridge in Xiang River. We designed Collision-proof equipment for the piers to prevent the collision between the bridge and ship. Considering the crash conditions of the local actual environment, the design could withstand the collision force created by a Ship loaded with 2000 tons, and plays a certain guiding function, so as to ensure the safety of the bridge. This paper had designed a variety of programs through UG,VPG/LS-DYNA model and simulation software, through comparing, eventually determined the optimal scheme.

Abstract: Based on the characteristic of the shortest time, no repetition and a huge financial loss at the car crash test, High Speed Photography system plays a strictly utilitarian role. This paper mainly analyses High Speed Photography system, from the perspective of a single system we can prove the feasibility about new crash test laboratory, meanwhile, this paper describes parameters, principle of HG-100K high speed camera adopted by our laboratory, at the same time, the application of the camera is analyzed generally in the experiment of car crash test in order to proving its practicability. High speed photography system is described further in the experiment of the car crash test.

Abstract: The electric power traction system in the Bridge/Shipping Crash Testing Laboratory, is the foundation of the crash test between the shipping and the bridge. In order to make sure the process more quickly, stably, accurately, centralized-control method has been applied in the electric power traction system of the Bridge/Shipping Crash Testing Laboratory in The Changsha University of Science and Technology, so the test flow has been controlled and finished automatically, the test data could be collected and recorded automatically, safety alarm, protect automatically and the history data could be recorded on the real-time, the test report form could been formed automatically and the manage function will be worked and so on. The problem of complexity of the test flow, the difficulty of the induction about the logic relationship, the strong electromagnetism interfere in the big current equipment, the machine shock is strong and so on would be solved, the traction system in the crash test would be made more real and mature.

Abstract: In order to overcome the shortcoming in the large structure crash test such as shipping-bridge crash testing, an indoor electric traction large structure crash testing laboratory had been developed independently on the basis of the success experience in the national vehicle crash testing technology, the available traction track is 216 meters long, and the shipping-bridge crash testing, vehicle-bridge crash testing, vehicle crash testing, vehicle rolling testing, vehicle-barrier crash testing, vehicle-traffic facilities crash testing and so on could be carried out in the laboratory, the maximum traction mass could reach 18000kg, and the maximum crash speed could reach 120km/h, therefore, a effective design method for large structure crash testing laboratory had been formed. The result shows that the all meet the requirement of the pre-expected purpose.

Abstract: FE models of both the single-layer Kiewitt reticulated domes and the impactor were developed incorporating ANSYS/LS-DYNA. Three failure modes for Kiewitt reticulated dome under impact load are discerned. Moreover, Global collapse of structure belongs to the progressive collapse, and is the most serious failure. After this, stress of members, velocity and strain energy of each component are introduced to display the progressive process of collapse. It shows that the dome does not defend impact load as a whole. Each component of structure is impacted and dented in turn. And the collapse enlarges from impact zone to the supports of dome. Furthermore, collapse relates to energy transform among kinetic energy, stain energy and potential energy of structure. Moreover, collapse will continue, if initial kinetic energy and release of potential energy of structure exceed the strain needed.