Papers by Keyword: Lateral Vibration

Abstract: This paper is dealing with the lateral vibration of simply supported beam induced by one crossing pedestrian. Effects of pedestrian on the structural vibration was simplified by deterministic, stationary, periodic forces, which were placed at the most efficient spot on the structure. A new approach to modeling of excitation of lateral vibration was also introduced. This model is based on the "real" trajectory of pedestrian's centroid and it also reflects fact, that the pedestrian is changing his position in time. Numerical solution of this problem was done by Newmark integration method with using modal decomposition technique.

Abstract: The paper deals with a dynamic response of footbridge structure which is loaded by a movement of pedestrians. Interaction between crowd and footbridge structure is a complex problem. It is important to take into account load generated by the movement of pedestrians during the computation, but also change of load influenced by a response of the structure. It means practically that the response of the structure has influence on the movement of pedestrians. Computation of the response has to be performed in several steps. The first step is backward modification of load represented by the crowd movement. Next step is recalculation of the structure with newly compiled load. This approach can bring near the real behaviour of the structure which is exposed by the continuous movement of pedestrians..

Abstract: Through the condition analysis of the drill rod during the mining horizontal drilling for gas drainage, the finite element model of the drill rod lateral vibration is established. The drill rod lateral vibration is related to the diameter and length of the drill rod. With the increase of the diameter of the drill rod, the natural frequency of the lateral vibration of the drill rod increases constantly. The increasing amplitude of the natural frequency at the larger diameter of the drill rod is larger than that at the smaller diameter. When the drill rod is longer, the natural frequency of the lateral vibration of the drill rod is lower. From the modal images of the drill rod, the lateral vibration of the drill rod is similar to the sine curve. During the horizontal drilling in coal seam, the drill rod contact and impact with the hole wall which will bring about the fatigue fault of the drill rod and the collapse of the hole wall.

Abstract: With the high-speed railway construction, studying of the vehicle-bridge vibration system increasingly important. This article established a range of high-speed trains linear model and standard high-speed railway 32 m span bridge model then a combination of both established based on ANSYS vehicle-bridge finite element model. Followed based on ANSYS high-speed train-bridge Coupled Vibration Simulation Analysis System. Analysis of a variety mound lateral stiffness, According to the analysis results of the piers of the basic principles. The bridge has been established based on the finite element model. Respectively, from the height of piers and pier-shaped two aspects to computational analysis the piers for bridge Coupled Vibration of Dynamic Response of Bridges. Provide a reference for the design of high-speed railway.

Abstract: This paper attempts to explain the motion behaviour of the marine riser coupled to a drill string when the vortex induced vibration (VIV) is involved. Vibrations have been reported to have a major effect on the drilling performance, affecting the rate of penetration (ROP), causing severe damages to the drilling tools and also reduces the efficiency of the drilling process. There are two major components of drilling tools that are subjected to vibration, namely the marine riser and the drilling string. Analysis of vibration in the marine riser and drill string are two topical areas that have individually received considerable attention by researchers in the past. Though these two subjects are interrelated, borne by the fact that the marine riser encapsulates and protects the drill pipe, there have been few attempts to investigate them together as a unity. Due to the complexities of the models, simplified assumptions were made in order to undertake the investigation by using staggered approach. The results were compared with the experimental and simulation data from the open literature. It was found that the maximum displacement with negative damping occurs at low frequency and rotation speed.

Abstract: Based on the uniform experimental design method and combining with the additional lateral pedestrian role derived from social force, this paper establishes human-bridge dynamic interaction model and calculates dynamic response of simply supported structures with different span, damping ratio, walking stride frequency and other parameters under the man-bridge dynamic interaction. The acceleration response spectrum is obtained by FFT transform of acceleration response. Then RMS-acceleration response spectrum is calculated in accordance with ISO overall frequency weighting method and the response spectrum envelope formula is fitted by parametric analysis.

Abstract: Frequently, in the design of machines, some of parameters that directly affect the rotordynamics of the machines are not accurately known. In particular, bearing stiffness support is one such parameter. Taking a rig shafting as an example, this paper studies the lateral vibration of the rig shafting with multi-degree-of-freedom by using finite element method (FEM). The FEM model is created and the eigenvalues and eigenvectors are calculated and analyzed to find natural frequencies, critical speeds, mode shapes. Then critical speeds and mode shapes are analyzed by set bearing stiffness changes. The model permitted to identify the critical speeds and bearings that have an important influence on the vibration behavior.

Abstract: In order to suppress the lateral vibration of high-speed train caused by track irregularity, the delayed feedback control is employed to suppress the vibration of the semi-active suspension system. The 1/4 vehicle mathematical model of semi-active suspension system is established. The amplitude of the bodys lateral vibration is large at some values of external excitation frequency for the passive suspension system, and it could be suppressed at some values of time delay, while the vibration of the bodys lateral vibration may be deteriorated at other values of time delay. The results show that the amplitude of the bodys lateral vibration could be suppressed about 50% when the suitable values of damping coefficient and time delay are chosen by comparing with the passive suspension system. The analytical results of this paper are in good agreement with the numerical simulation.

Abstract: This paper conducts an analytical research on the use of bridges, and discusses how the vibration of bridges is affected by the healthiness of piers. Meanwhile, Impact Vibration Test Method is introduced, by which the modal parameter of bridges can be tested. A lot of dynamic tests of piers are conducted by using this method. By analyzing data and identifying modal information of piers, this paper made a conclusion on the general law of the impact each parameter has on characteristic frequency of the piers. The bridge finite-elemental model is constructed according to the actual structure of piers, the impact vibration test load stimulated, then computed and analyzed with the dynamic time-history method. Bases on the comparison between test result and frequency of Time-domain transverse velocity received the results of the analyses identify the frequency spectrums, the validity of the Impact Vibration Test Method is verified.

Abstract: ndoor steel stairs, which are usually designed by professional construction companies, are controlled by the stiffness and strength. However the vibration problem is not considered and may lead to the problem of comfortability and even safety. This paper focuses on vibration of steel stairs by a case study. Both the vertical and the lateral vibration are concerned in the study by site test and numerical analysis. Based on the test and analytical results, the vibration evaluation is done for it. Finally some suggestions for indoor steel stair are given to reduce the problem of vibration.