Applied Mechanics and Materials Vols. 178-181

Abstract: Based on FEM program ANSYS and the OpenGL graphics, this paper develops the parametric modeling module and the computing module of the multi-tower suspension bridge, this module being embedded into the ANSYS system, and the parametric modeling module parameters can be entered by way of interface, which establish fast a multi-tower suspension bridge model. Calculation module can establish load conditions for the features of road bridge and specifications, in which multiple conditions can be defined and solved automatically. Post-processing part of the solution also for the results of the subtotals and select the output, so that the results of the output and finishing work has become more convenient and easier, and also the results can also be saved in word, excel and other different file types.

Abstract: The linear and nonlinear stability of continuous rigid frame bridge with thin-wall piers is analyzed by using the current FEM software. Linear stability analysis indicates that coefficient of stability in cantilever stage is poorest. Two aspects are included in nonlinear stability analysis. The first one, only geometric nonlinearity is considered and the other one, geometric nonlinearity and material nonlinearity are considered simultaneously. The results show that material nonlinearity is a factor to stability coefficient that can not be overlooked. Considered the dual non-linearity, the stability coefficient descends consumedly.

Abstract: Abstract. This paper consider the restoring force and the coulomb force between the cable and the rivulet comprehensively ,Use Alembert principle to establish two-degree coupled nonlinear motion differential equations of rain-wind-induced vibrations of the cable structure . The equation was analyzed by numerical calculation method with mathematic program . The phase diagrams of cable and water-line were achieved, Also analyzed the effect of the density ratio、viscosity and other parameters on the cable amplitude . Finally through the calculation of Lyapunov performance index obtained the system exist chaotic region. The Phase trajectory and the time-history curve with time extension will be increasingly larger , which can,t be predicted ,thus the chaos phenomenon of system being better interpreted .

Abstract: A new vehicle active suspension with Electro-Hydrostatic Actuator (EHA) is suggested. The system consists of two parts: spring and actuator with variable control force. The actuator includes hydraulic cylinder, hydraulic pump, controller, etc. According to bond graph principle, bond graph model of EHA active suspension are built. For vehicle active suspension system, unavoidable time delay may appear in the controllable course. Time-delay influence on the dynamic performance of vehicle active suspension is analyzed. Physical prototype and experimental rig for EHA active suspension is built. Then the tests of suspension prototype with time-delay control are carried out on the developed test rig. The results show that the sprung mass acceleration of the active suspension with time-delay compensation significantly declines by 11.56% under the road input of 1.1Hz and by 12.8% under the road input of 1.5Hz

Abstract: Based on the Nenjiang Bridge located in the Qi-Gan expressway and using the finite element software ANSYS, we analysis the influences of solar radiation, free air temperature, inside temperature, wind speed, thermal conductivity of concrete, section height, flange plate length and bridge pavement on the temperature field of PC box-girder in this paper. And the solar radiation, thermal conductivity of concrete and bridge pavement is presented as the leading factors for the temperature field of PC box-girder.

Abstract: The Rayleigh wave testing method is one of the in-situ nondestructive tests, which the theory is quite mature, and it characterized by portable equipment, well operability and fast detection speed. So it can greatly improve the efficiency of the compaction detection of the highway embankment, and it especially has incomparable advantage for the compaction quality detection and monitoring of earth-rock filled or rock filled embankment. In the paper, by the analysis of the field wave testing result of the rock-filled embankment, obtained the velocity of the rock-filled embankment, and researched the relationship of the field wave velocity and the dry density, the relationship of the field wave velocity and the porosity. The fitted formulas between the wave velocity and the dry density and porosity were established, and the results indicate there are well correspondences between the wave velocity and the dry density and porosity. The relationship of between porosity and the shear velocity of the rock-filled is a good linear correlation, and the relationship of between dry density and shear wave velocity of the rock-filled is a good power function relation.

Abstract: On the basis of typical theory on vibration analysis of the bridge and vehicles, by using the ANSYS software, a finite element model of the bridge is established. The character on dynamic response of bridge is analyzed when harmonic Loads with different frequencies pass through the bridge, and inner-force of bridge is given. The research will give beneficial rules for the vibration control of bridge under moving loads.

Abstract: The running performance of train on Shangbaipu bridge is analyzed with energy random analysis theory for derailment. The calculated result shows that the running safety of train cannot be ensured with the existing operation condition, and the measurement of rate-limiting or reinforcement is needed to be taken for this bridge. A method for establishing index of traffic safety for railway bridge is proposed, and the detailed contents are as follows. The lateral amplitude on the middle of beam is determined as index for traffic safety for beam-pier system. The critical beam-pier system with which the running performance of train can be guaranteed is determined. The lateral amplitude of critical beam-pier system is calculated and determined as limit value for traffic safety. The limit value of lateral amplitude for traffic safety for Shangbaipu bridge is determined as L/4000.

Abstract: In order to analyze the shrinkage, creep effect of the old and new concrete beam after small and medium-sized span concrete slab bridge was broadened, slab beam was taken as an example, and the vertical stress of the old and new beam caused by beam body shrinkage and creep effect was analyzed, and the influence of the different construction conditions on the vertical stress of cement slab was compared by making use of different calculation methods.At the same time,the redistribution of the stress at the juncture caused by the different shrinkage, creep of the new and old concrete beams because of the time difference was analyzed. The analysis results show that the longitudinatensile stress on the new beam caused by shrinkage and creep may lead to longitudinal crack of new beams.

Abstract: In order to know the bridge bearing operation condition, monitoring bearing displacement was an alternative way. Considering the special field environment of rail elevated bridge and some existing problems of EM-based sensors, needle-shape differential FBG displacement sensors were designed which ensured the long-term stability monitoring under EMI environment. Comparing to the wire-shape FBG displacement sensor, the contact measure type through the sensor needle-shape rod in this paper not only simplified the installation process in-situ, but also could reflect the accurate test direction of bridge bearing. The good linear relationship between sensor wavelength and load verified the rationality of designed differential structure. The practicability in actual engineering application of needle-shape FBG sensor was revealed by a certain rail elevated bridge bearing displacement continuous monitoring results.