排序方式: 共有13条查询结果,搜索用时 24 毫秒
1.
2.
In-plane auto-parametric stochastic vibration of inclined cables subjected to Gaussian white noise in transverse bridge orientation is investigated. Based on Newton's laws of motion and Galerkin's modal truncation principle, the influences of geometry nonlinearity induced by sag and large displacement of cables and the initial equilibrium state are taken into account. Meanwhile, the three-dimensional non-linear differential equations of inclined cables for coupling vibration are deduced, equivalent stochastic linearization method is applied to derive the 14-dimensional first-order nonlinear differential equations of state vectors, and the Runge-Kutta integration method is utilized to obtain the root mean square (RMS) response. Results show that when the transverse random excitation imposed on the stayed cable exceeds a critical value, the in-plane transverse vibration of the cable are excited due to tim auto-parametric nonlinear coupling, and the critical value of random excitation increases with the damping ratio. In this motion, the cable response possesses non-stationary characteristics, even though the loading keeps stationary. 相似文献
3.
4.
5.
运用大质量法,建立并推导了长大跨度桥梁考虑行波效应的分析模型及解析方程。以内蒙古小沙湾黄河特大桥为工程背景,选取墩身刚度、地震波视波波速、地震波激励方向等主要参数,建立动力计算模型,对该桥上述各种参数工况下地震时程反应作了参数对比分析研究。利用分析结果,探讨了同类桥梁在各种参数变化情况下墩顶位移和墩底内力的变化规律。 相似文献
6.
Temperature field and its variation with time are necessary for analyzing the thermo-mechanical performance of mass concrete structures at their early ages. This paper carries out a temperature field simulation analysis for an original segment of a real box girder bridge with the finite element software ANSYS. Two representative exothermic rate models are used to describe the heat-releasing process caused by the cement hydration in concrete. The exothermic rate model that conforms to reality more closely is recognized by comparing the simulation results with the data gathered from the optical fiber temperature sensors pre-embedded in the original segment. The air temperature and wind velocity that constitute thermal boundary conditions are determined in the light of the local meteorological department and correlative research achievements of recent years. Moreover, the consideration for the steel formwork acting as a barrier to heat loss is also proved to be beneficial to improve the simulation effect. 相似文献
7.
8.
考虑拉索局部振动的斜拉桥地震时程响应分析 总被引:1,自引:0,他引:1
为探讨拉索局部振动对斜拉桥抗震性能的影响,考虑垂度效应和初始静平衡状态,导出了某大跨度斜拉桥拉索一阶自振频率的解析解,并求得该桥斜拉索自振频率的多段拉索模型有限元解.通过输入2种幅值相等但频谱特性不同的地震动激励,分析了拉索局部振动对主梁振动的影响.结果表明:拉索自振频率的有限元解与解析解吻合较好,表明该有限元模型能正确反映斜拉索的振动特性.当主梁竖向低阶振动模态频率与地震卓越频率不一致时,拉索局部振动对主梁产生“附加阻尼”作用;反之,拉索与主梁耦合振动对主梁产生“振动放大”效应. 相似文献
9.
10.