Applied Mechanics and Materials Vols. 275-277

Abstract: The present paper is focused on the torsional instabilities of the intermediate shaft in a two stage gear system. A theoretical model is established taking account in the torsional flexibility of the intermediate shaft and the meshing time-varying stiffness of the gears. Multiple scale method is applied to analysis the instability areas of the gear system for which the generalized modal coordinate is adopted. The result is certificated by numerical integrals of the dynamic equations by Runge-Kutta Method.

Abstract: The parameters of high speed trailer wheel were identified by modal test using hammering method. Based on the actual measured dynamic stress data, the frequency spectrum was obtained and the transfer function was analyzed. Compared the results of the frequency spectrum analysis and the modal parameters of the wheel set, the primary frequency in frequency analysis and all the frequencies with higher amplitude in the transfer function were far from the natural frequency of the wheel set. The results show that the train is safe running on high speed line.

Abstract: The homoclinic tangency for a rotor-active magnetic bearings (AMB) system with the time-varying stiffness are considered in this paper. The zeros of Melnikov equation are paid more attentions and a 3-order zero was gained and some numerical results under the parameter perturbations were shown.

Abstract: Three L-shaped columns with HRB500 reinforcement were tested under low cyclic loading. The effect of stirrup ratios on damage characteristic, hysteretic characteristic, rigidity degradation and energy dissipation capacity was analyzed to research the hysteretic behavior of L-shaped columns with HRB500 reinforcement. The result shows that the damage characteristic and the hysteretic characteristic of L-shaped columns with HRB500 reinforcement are improved with the increase of stirrup ratios. The energy dissipation capacity of L-shaped column was also enhanced after ultimate load with the increase of stirrup ratios.

Abstract: Simple joint is a common connection type in tubular structures. In this joint, one or more tubes are welded directly on the surface of another tube. Local buckling occurs in panel zone when the joint load is heavy, and such local buckling will reduce the bearing capacity and stiffness of the joint. In order to improve bearing capacity of tubular joints, the joint needs to be strengthened. In this paper, the bending performance of the joint will be enhanced by welding two annular plates inside the surface of panel zone of chord member. By ANSYS finite element program, the bearing capacity of the joint with different inner annular plate was analyzed, including design bearing capacity and ultimate bearing capacity. The results showed that comparing to annular plate thickness variation, the width variation and interval variation have much more influence on the bearing capacity of the joint.

Abstract: Welded rectangular steel tubular joints have been widely used in large span complicated steel structure engineering .With the type of the joints and structural measures complicated, there is no suitable joints theory formula in design specifications. In this paper, two different structural measures types of umbrella steel truss # 8 joints and 68 # joints in a Railway Station are static analysis ,which is by means of finite element software ANSYS and based on the principle of the joints member loading simultaneously. The analysis results show that: in the case of the joints member loading simultaneously, the carrying capacity variation of each member is not uniform coordination; With the different angle between the branch pipe of joints and main pipe, the changes of the degree of stress concentration in the four side surfaces of the member is different. The maximum difference is about 2-fold; compared 68 #joint with 8 # joint, its degree of stress concentration on the overall is small, which prove that structural measures of its domain joints is reasonable.

Abstract: Taking South-to-North Water Diversion Bridge, a continuous composite box-girder bridge with corrugated steel webs, as the engineering background, the cantilever beam end’s deflection calculation formulae considering shear deformation were deduced by using energy method. Comparing with finite-element analysis (FEA) values and measured values, the formulae which considered both concentrated force and uniform load have enough accuracy. Results show that, shear deformation’s proportion is more obvious in overall deflection of such box-girders which have smaller span ratio, and it’s more than 30%. For continuous composite box-girder bridge with corrugated steel webs, contribution of shear deformation to overall deflection should not be ignored.

Abstract: For the rapid erection of FRP truss bridge, based on the FRP material characteristics, it was put forward to a suitable FRP truss bridge construction hoisting technology. Hoisting technology was divided into two types: integral hoisting and segment hoisting. This article mainly researched and analyzed the aspect of the selection of hoisting scheme, the selection of hoisting equipment and hoisting point, expounded emphatically the selection principle and method of hanging point when hoisting, and checked hoisting point in different cases. Certain references were provided for the subsequent FRP truss bridge hoisting erection.

Abstract: Through the ansys software, we analysised the space truss structures for its dynamic response and observed its formation of frequency diagram . Based on the analysis of the observation ,natural vibration rules of the space truss structure are discussed. In the process of analysis, We got the conclusions of the support conditions of the change and support amount of adjustment to the influence of the space truss structure vibration frequency.

Abstract: The mechanical behavior of prestressing, temperature ,creep & shrinkage in construction procedure are studied, then construction analysis are integrated into structural nonlinear analysis by defining construction procedure as state nonlinear. The “time effect” and “route effect” are defined in large-scale structure, and their essences are studied with a general format of displacement method.