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1.
This paper presents a nonlinear dynamic model for simulation and analysis of a kind of parametrically excited vibration of
stay cable caused by support motion in cable-stayed bridges. The sag, inclination angle of the stay cable are considered in
the model, based on which, the oscillation mechanism and dynamic response characteristics of this kind of vibration are analyzed
through numerical, calculation. It is noted that parametrically excited oscillation of a stay cable with certain, sag, inclination
angle and initial static tension force may occur in cable-stayed bridges due to deck vibration under the condition that the
natural frequency of a cable approaches to about half of the, first model frequency of the bridge deck system. A new vibration
control system installed on the cable anchorage is proposed as a possible damping system to suppress, the cable parametric
oscillation. The numerical calculation results showed that with the use of this damping system, the cable oscillation due
to the vibration of the deck and/or towers will be considerably reduced.
Project supported by National Natural Science Foundation of China (No. 59978044) 相似文献
2.
Nonlinear vibration can cause serious problems in long span cable-stayed bridges.When the internal resonance threshold is reached between the excitation frequency and natural frequency,large amplitudes occur in the cable.Based on the current situation of lacking corresponding constraint criteria,a model was presented for analyzing the dynamic reliability of coupling oscillation between the cable and tower in a cable-stayed bridge.First of all,in the case of cable sag,the d'Alembert principle is applied to studying the nonlinear dynamic behavior of the structure,and resonance failure interval of parametric oscillation is calculated accordingly.Then the dynamic reliability model is set up using the JC method.An application of this model has been developed for the preliminary design of one cable-stayed bridge located on Hai River in Tianjin,and time histories analysis as well as reliability indexes have been obtained.When frequency ratio between the cable and tower is approaching 1∶2,the reliability index is 0.98,indicating high failure probability.And this is consistent with theoretical derivation and experimental results in reference.This model,which is capable of computing the reliability index of resonance failure,provides theoretical basis for the establishment of corresponding rule. 相似文献
3.
INTRODUCTION The cable-stayed-suspension (CSS) hybridbridge is developed from the traditional cable-stayedbridge and suspension bridge, and has some advan-tages of the two bridge types described as follows: 1. As compared with the suspension bridge of thesame span length, the suspension portion is greatlyshortened, so the tensional forces in the main cablesare greatly decreased, which helps to decrease theconstruction costs of the main cables and the massiveanchors, and the difficulty of… 相似文献
4.
This paper proposes a new numerical simulation method for analyzing the parametric vibration of stay cables based on the theory of nonlinear dynamic response of structures under the asynchronous support excitation. The effects of important parameters related to parametric vibration of cables, i.e., characteristics of structure, excitation frequency, excitation amplitude, damping effect of the air and the viscous damping coefficient of the cables, were investigated by using the proposed method for the cables with significant length difference as examples. The analysis results show that nonlinear finite element method is a powerful technique in analyzing the parametric vibration of cables, the behavior of parametric vibration of the two cables with different Irvine parameters has similar properties, the amplitudes of parametric vibration of cables are related to the frequency and amplitude of harmonic support excitations and the effect of distributed viscous damping on parametric vibration of the cables is very small. 相似文献
5.
Stay cables, the primary load carrying components of cable-stayed bridges (CSBs), are characterised by high flexibility which increases with the span of the bridge. This makes stay cables vulnerable to local vibrations which may have significant effects on the dynamic responses of long-span CSBs. Hence, it is essential to account for these effects in the assessment of the dynamics CSBs. In this paper, the dynamic responses of CSBs under vehicular loads are studied using the finite element method (FEM), while the local vibration of stay cables is analyzed using the substructure method. A case study of a cable-stayed steel bridge with a center span of 448 m demonstrates that stay cables undergo large displacements in the primary mode of the whole bridge although, in general, a cable’s local vibrations are not obvious. The road surface roughness has significant effects on the interaction force between the deck and vehicle but little effect on the global response of the bridge. Load impact factors of the main girder and tower are small, and the impact factors of the tension of cables are larger than those of the displacements of girders and towers. 相似文献
6.
张天瑜 《江苏广播电视大学学报》2006,17(6):71-74
通过建立RLC阻尼振荡电路的系统模型,得到三种不同的阻尼振荡类型及其通解的形式,利用M atlab程序对后两类阻尼振荡电路的时域和频域进行编程描述,对此两者仿真波形,证实了两种方法的有效性,同时指出了第5条临界阻尼非振荡波形失真的原因。 相似文献
7.
8.
以机械传动系统中的斜齿轮啮合为研究对象,在考虑时变刚度、齿侧间隙和啮合误差的情况下,建立了十自由度斜齿轮非线性振动数学模型。以斜齿轮结构参数作为灵敏度分析参数,采用数值分析方法分别研究了斜齿轮系统振动加速度均方根值对齿轮质量、支撑刚度和支撑阻尼的灵敏度。结果表明:主、被动轮横向（y向）振动对各参数敏感度较低,横向振动（x向）与被动轮扭转振动对质量参数、刚度参数、阻尼参数较为敏感,被动轮扭转振动受到阻尼的影响很大,灵敏度在扭转振动固有频率处变化较大。 相似文献
9.
通过建立1/4悬架系统的理论数模,分析阻尼系数影响系统的幅频特性.在不同的振动频率范围内,阻尼的相应变化将改善悬架系统的输出性能. 相似文献
10.
A three-dimensional finite element model was established for a large span concrete filled steel tubular (CFST) arch bridge which is currently under construction. The arch rib, the spandrel columns, the prestressed concrete box-beam, the cast-in-situ concrete plate of bridge deck, the steel box-beam and the crossbeams connecting the two pieces of arch ribs, were modeled by three-dimensional Timoshenko beam elements (3DTBE). The suspenders were modeled by three-dimensional cable elements (3DCE). Both geometric nonlinearity and prestress effect could be included in each kind of element. At the same time a second finite element model with the same geometric and material properties excepted for the sectional dimension of arch rib was set up. Static dynamic analyses were performed to determine the corresponding characteristics of the structure. The results showed that the arch rib's axial rigidity could be determined by static analysis. The stability and vibration of this system could be separated into in-plane modes, out-of-plane modes and coupled modes. The in-plane stability and dynamic characteristics are determined by the arch rib's vertical stiffness and that of out-of-plane is determined by the crossbeams' stiffness and arch rib's lateral stiffness mainly. The in-plane stiffness is much greater than that of out-of-plane for this kind of bridge . The effect of geometric nonlinearity and prestress effect on bridge behavior is insignificant. 相似文献
11.
论述了一种抑制载重绳索参数激励横向振动的简便方法. 假设绳索底端的质量受到一个垂直简谐激励并忽略载重绳索高阶振型的影响, 载重绳索的运动方程可以用一个带有立方非线性项的Mathieu方程来描述. 根据Mathieu方程的有关理论, 在载重绳索系统中, 当索端质量垂直振动的频率接近绳索横向振动固有频率2倍时, 一旦索端质量垂直振动的幅度超过某个临界数值时, 绳索将产生参数共振. 为了避免这种现象, 建议在索端质量上加装一个减振器以削减索端质量的垂直振动, 进而抑制绳索的横向振动. 实验验证了该减振方案的有效性. 相似文献
12.
Hao WANG Tian-you TAO Huai-yu CHENG Ai-qun LI 《浙江大学学报(A卷英文版)》2014,(10):798-812
研究目的：为超大跨度斜拉桥抗风设计与抖振控制提供参考。研究方法：基于ANSYS建立了苏通大桥三维有限元模型,并在MATLAB平台模拟了苏通大桥三维脉动风场。考虑主梁断面气动自激力,进行了苏通大桥抖振时域分析。根据苏通大桥动力特性和抖振时域分析结果,重点分析了多重调谐质量阻尼器（MTMD）用于抖振控制的参数敏感性。考虑MTMD的控制效果、建造费用、施工难度及鲁棒性等因素建立了关于MTMD设计参数的目标函数,并基于一阶优化算法进行目标函数最优解的非线性搜索,据此获得了MTMD在约束条件下的最优设计参数。重要结论：1.苏通大桥侧向抖振位移主要由第一阶侧弯振型控制,竖向抖振位移主要由第一阶竖弯振型控制;2.MTMD的控制效果对设计参数的变化十分敏感,其中质量比和频带宽敏感性更强;3.MTMD的最优设计参数可以通过一阶优化算法获得,并可通过零阶优化算法对优化结果进行验证;4.采用优化后的MTMD设计参数,苏通大桥的抖振响应可以得到明显抑制,且侧向抖振控制效果更加明显。 相似文献
13.
以振动压路机为例,对振动压路机压实过程建立了三自由度线性动力学方程,分别运用欧拉数值积分法和频域分析法进行了仿真.仿真结果显示,两种方法计算出的压路机系统响应结果一致.数值积分法所得的系统响应包含瞬态响应和稳态响应,计算时间长,对初始条件要求严格;而频域分析法得到的系统响应只有稳态响应,计算时间短,但对采样频率有一定的要求. 相似文献
14.
A friction damper device (FDD) is used for vibration control of an existing steel jacket platform under seismic excitation.
First, the damping is presented for vibration mitigation of structures located in seismically active zones. A new method for
quick design of friction or yielding damping devices is presented. The effectiveness of the damping system employing such
FDDs in a jacket platform is evaluated numerically. The influence of key parameters of the damping system on the vibration
suppression of the offshore structure is studied in detail. To examine the vibration control effectiveness of the FDD for
the jacket platform, performance of the controlled structure under the seismic forces is studied using numerical simulations.
A parametric study is undertaken to discover the optimized slip load and brace area of the FDD. It is shown that the FDD is
effective in mitigating the dynamic responses of the offshore platform structure. 相似文献
15.
采用理论分析及数值计算方法研究了一类弹簧质量系统在水平面上的运动,得出系统参数及振幅对该类系统非线性周期振动性质的影响规律,丰富了非线性振动的研究. 相似文献
16.
微推进器作为微小卫星在轨运行的核心部件,对其推力大小的精确测量显得尤为重要。为了克服传统机构存在诸如平衡不稳定、响应慢、需要克服摩擦力等不足,一种基于枢轴承的钟摆型推力测试系统被提出用于微推力测试。首先,建立了该测试系统的动力学模型,并对其阶跃响应进行仿真分析,结果显示响应曲线出现超调、震荡等不稳定的现象。为改善测试系统的动态特性,采用双线性法设计了一动态补偿滤波器,并建立了包含补偿的测试系统的动力学模型。对其动态响应进行数值仿真分析。结构显示固有频率由2．2提高到3．32Hz,阻尼系数由0．02提高到0．707,有效改善了测试系统的动态特性。 相似文献
17.
发电机组轴系弯扭耦合电磁激发振动数学模型 总被引：1，自引：0，他引：1
依据机电分析动力学理论 ,找到了发电机组定转子间气隙磁场的能量 ,得到了作用在发电机转子上的电磁力 (矩 ) ,建立了一个基于分段连续质量的发电机组轴系弯扭耦合电磁激发振动的数学模型 .该模型考虑了不平衡、陀螺力矩、转动惯量、剪切变形及阻尼的影响 ,是一个比较精确的模型 .对全面探索发电机组的振动规律具有应用价值 相似文献
18.
通过数值实验,发现立方振子在线性阻尼中运动时存在欠阻尼、临界阻尼和过阻尼3种状态,总结出临界阻尼常量随系统参数及初始条件变化的定量公式,并得出欠阻尼状态下振幅的衰减规律. 相似文献
19.
研究目的：创新要点：为多塔斜拉桥在一致激励和非一致激励下地震响应的研究提供地震模拟振动台全桥试验方法,并有助于加强多塔斜拉桥抗震性能和抗震设计的认识。1．建立了地震模拟振动台多台阵试验方法,并首次将其应用于多塔斜拉桥全桥比例缩尺模型的地震响应分析之中;2．通过地震模拟振动台试验,揭示了多塔斜拉桥在多点一致激励和多点非一致激励的地震响应特性并提出了多塔斜拉桥在强震下的破坏模式。研究方法：1．基于动力相似理论,设计与制作了多塔斜拉桥的全桥比例缩尺模型（图2）;2．利用地震模拟振动台多台阵试验,根据在不同地震波作用下和考虑行波效应后多塔斜拉桥模型的主梁和主塔响应,分析了多塔斜拉桥在多点一致激励和多点非一致激励的地震响应特性（图5～图8）;3．根据在地震波不同强度作用下多塔斜拉桥模型的主梁和主塔响虚,分析了多塔斜拉桥在强震下的破坏模式和地震响应（图9）。重要结论：1．江心波作用下该多塔斜拉桥的地震响应大于其他三种地震波;2．多塔斜拉桥在抗震设计时需要考虑行波效应的影响;3．在El-Centro波的加速度峰值高达4．0m／s^2时,多塔斜拉桥模型出现了支座破坏。 相似文献
20.
ZHANG Xin-jun YING Lei-dong 《浙江大学学报(A卷英文版)》2007,8(5):693-698
To gain understanding of the applicability of carbon fiber reinforced polymer (CFRP) cable in cable-supported bridges, based on the Runyang Bridge and Jinsha Bridge, a suspension bridge using CFRP cables and a cable-stayed bridge using CFRP stay cables are designed, in which the cable’s cross-sectional area is determined by the principle of equivalent axial stiffness. Numerical investigations on the aerodynamic stability of the two bridges are conducted by 3D nonlinear aerodynamic stability analysis. The results showed that as CFRP cables are used in cable-supported bridges, for suspension bridge, its aerodynamic stability is superior to that of the case using steel cables due to the great increase of the torsional frequency; for cable-stayed bridge, its aerodynamic stability is basically the same as that of the case using steel stay cables. Therefore as far as the wind stability is considered, the use of CFRP cables in cable-supported bridges is feasible, and the cable’s cross-sectional area should be deter-mined by the principle of equivalent axial stiffness. 相似文献