共查询到19条相似文献，搜索用时 140 毫秒
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滚动FPS和MR阻尼器混合基础动力学模型及仿真 总被引：2，自引：0，他引：2
本文中作者将新型双磙子FPS系统的动力学方程推广到由滚动FPS和MR阻尼器组成的混合隔震基础系统,得到了更便于应用的水平分量形式的运动微分方程,并将与FPS有关的力和MR阻尼力处理成力源项,构造了可以方便地考虑不同上部结构形式的MATLAB/SIMULINK仿真模型。采用RD-1005型MR阻尼器和模糊逻辑控制器,在两个典型的地震输入情况下对混合系统进行了振动控制仿真。仿真结果表明,本文建立的混合隔震基础系统的动力学模型是正确和精确的,直接利用动力学模型进行前向计算可避免附加的模型误差且计算效率高,而仿真模型中将不同的力源由分开的块组成,使得仿真设计非常方便快捷。 相似文献
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在激光干涉绝对重力仪中,参考棱镜在背景振动和系统自振的作用下呈现复杂的振动模式,严重影响了整机的测量准确度.针对此问题,本文基于磁悬浮原理设计了参考棱镜的反馈式两级振动隔离系统,建立了系统的动力学模型,在不同的反馈方式下推导了相应的传递函数,进行了Matlab仿真分析以确定最优的反馈方式.系统仿真结果表明绝对速度反馈方式的隔振效果可达100 dB,与自主研发的Age-110型激光干涉绝对重力仪的联合测试结果表明,该隔振系统可将Age-110的测量精度再提高1.5倍. 相似文献
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为了准确分析FPS隔震桥梁的纵向地震碰撞反应,针对一典型3跨FPS隔震简支梁桥,建立了考虑FPS双向耦合效应和梁缝处三维碰撞效应的非线性动力计算模型,分析双向地震作用下FPS隔震简支梁桥纵向地震碰撞反应;研究支座半径和摩擦系数对简支梁桥纵向地震碰撞反应的影响规律。研究结果表明:横向地震作用会增大简支梁邻梁间纵向地震碰撞次数和碰撞力,降低墩底纵向剪力;为减小地震碰撞反应,设计时可适当增大支座半径和支座摩擦系数。 相似文献
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将摩擦摆(FPS)引入到网壳结构的隔震控制中。文中首先阐明了FPS的工作机理和本构关系,建立了FPS隔震网壳结构的振动方程。通过双层球面网壳结构的数值算例考察了隔震和无控结构在单向和三向地震作用下的振动响应以及FPS的控制效果。研究结果表明,FPS具有良好的隔震和耗能效果,可有效地应用于球面网壳结构的振动控制。 相似文献
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为研究双线地铁运营时隔振沟的减振效果,基于2.5维有限元法建立双线地铁列车-轨道-地基土体耦合分析模型。模型克服现有研究将轨道结构简化为弹性地基欧拉梁的缺陷,引入实际钢轨动力学参数,实现双线地铁列车荷载下隔振沟对周围地基的隔振效果分析,比较空沟、填充沟两种不同隔振措施的减振特性,并对填充沟隔振影响因素进行系统的参数分析。研究结果表明:双线运营地铁荷载下,空沟隔振作用体现在沟后范围内,填充沟减振范围更广且效果更好,相比空沟更具工程实用性;填充沟在沟深较小时也能发挥良好的减振作用,增大沟深、沟宽均可有效提高减振效果。研究成果可为今后双线地铁隔振设计与施工提供有益参考。 相似文献
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为研究高速列车作用下,层状地基中空沟对场地振动的隔振效果,基于车辆-轨道耦合动力学理论及有限元法,对建立完善高速车辆-无砟轨道-地基耦合系统动力学模型进行仿真计算,分析设置空沟对场地振动的影响,并探讨了空沟的深度、位置、宽度以及列车速度的影响。结果表明：设置空沟加强了沟前场地的振动,但可使空沟后方地基的竖向和水平振动水平大幅减小,但在特定位置存在振动放大区,引起隔振效果减弱;过浅或过深的空沟均不能达到最优隔振效果;对于在线路旁需要特殊隔振的场地,存在一个适用于其本身的空沟最佳位置;空沟的宽度对隔振效果无明显影响;空沟对更高速度运行列车引起场地竖向和横向振动的隔振效果更明显。 相似文献
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主动隔振系统具有隔振频带宽,能够在低频处取得较好隔振效果的优点,因而成为研究的热点。基于单级弹簧主动隔振系统建立数学模型,着重分析了系统位移反馈、速度反馈和加速度反馈3种反馈量对系统隔振性能的影响。结果表明:位移反馈使系统固有角频率提高,低频处隔振效果增强,而高频处隔振效果略有降低;速度反馈使系统在固有角频率附近的隔振效果有很好的改善,但是在其他频段的隔振效果基本没有变化;加速度反馈使得系统固有角频率减小,并且在高频段的隔振效果增加。这对主动隔振系统控制器的设计具有实际指导意义。 相似文献
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根据观测的O3总量场序列资料反演区域系统的非线性演化方程,采用自然正交分解方法,由空间函数构造相空间正交基,将时间函数（主成分）嵌入对应于系统状态变量,计算得到O3层系统的分数维D2＝2．9,说明它属于低自由度的混饨动力学系统．主成分的时间尺度层次特征,反映了O3层的各种动力行为,它们是动力学系统再现的集合,用于反演动力学方程可描述不同层次扰动的约束及相互作用的性质,刻画出系统的演化形态．为研究系统成分的内在关系,在三维和四维相空间中分别建立动力学方程。通过对比分析,两者描述O3层动力行为的差异表现在较低层次的系统成分中,表明在系统成分相互作用过程中高层次对低层次信息的不完全确定性。 相似文献
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为了研究分层土地基（上层为粘土层,下层为砂层）条件下几何参数对单排混凝土桩的隔振效果,该试验通过缩尺比例为1∶15的缩尺模型试验,以激振器作为点振源产生振动波向四周扩散,通过对比单排桩前后两侧振动加速度极值,清晰地展现出了单排桩对振动波的的影响区域,并得到了几何参数的隔振影响作用。在该试验条件下得出结论:相对于其他影响因素,桩长是影响隔振效果的重要参数,当桩长参数由0.28增至0.57时可提高约9％的隔振面积,同时增加桩长和隔振区长度可使隔振区域振幅大幅度减小与有效隔振面积大幅增加,但同时会造成桩前一侧振动增强;对于低频振动,单排桩隔振屏障对中频和高频有更好的隔振作用,该试验条件下隔振效果可相差约3％,且频率越高,穿透性越强,且将在桩后形成一个振动加强区;增加振源距可有效提高隔振效果,但当频率较低时,中远振源的隔振效果相近。 相似文献
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<正>A theoretical model of a friction pendulum system(FPS) is introduced to examine its application for the seismic isolation of spatial lattice shell structures.An equation of motion of the lattice shell with FPS bearings is developed.Then, seismic isolation studies are performed for both double-layer and single-layer lattice shell structures under different seismic input and design parameters of the FPS.The influence of frictional coefficients and radius of the FPS on seismic performance are discussed.Based on the study,some suggestions for seismic isolation design of lattice shells with FPS bearings are given and conclusions are made which could be helpful in the application of FPS. 相似文献
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本文推导了FPS(Friction Pendu lum System)隔震结构在平移-扭转耦联情况下的动力反应方程,计算了单层框架结构的地震响应。分析了上部结构偏心对地震反应的影响,对比了结构在不同偏心时的反应并分析了FPS隔震装置的摩擦系数、滑道半径对其抗震性能的影响。 相似文献
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Introduction The phenomenon of water level tide was discovered at Duchort diggings, Czech in 1879. By 1939, Theis, an America hydrogeologist, confirmed that periodical wave of the well water level is caused by the solid tide. In 1964, Melchior, a Belgium geophysist, began to make research on this phenomenon. Then Cooper (1965), Bredehoeft (1967) and WANG, et al (1988) followed. In China the study on water level tide began with 1970s, and the study on well water level phase lagging began … 相似文献
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Influence of FPS bearing properties on the seismic performance of base‐isolated structures 
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下载免费PDF全文 The paper analyzes the influence of friction pendulum system (FPS) isolator properties on the seismic performance of base‐isolated building frames. The behavior of these systems is analyzed by employing a two‐degree‐of‐freedom model accounting for the superstructure flexibility, whereas the FPS isolator behavior is described by adopting a widespread model that considers the variation of the friction coefficient with the velocity. The uncertainty in the seismic input is taken into account by considering a set of natural records with different characteristics scaled to increasing intensity levels. The variation of the statistics of the response parameters relevant to the seismic performance is investigated through the nondimensionalization of the motion equation and an extensive parametric study carried out for different isolator and system properties. The proposed approach allows to explore a wide range of situations while limiting the required nonlinear response history analyses. Two case studies consisting of base‐isolated building frames described as shear‐type systems are finally investigated in order to demonstrate the capabilities of the proposed simplified model in unveiling the essential characteristics of the performance of buildings isolated with FPS bearings. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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An analytical representation of the bilinear hysteretic characteristic is presented. Using this representation, the response of a single-degree-of-freedom bilinear hysteretic system subjected to non-stationary random excitation is examined by equivalent linearization. An ordinary differential equation is derived for the covariance matrix of the response. Numerical examples are presented and the accuracy of the approach is demonstrated. Extension of the approach to a wider class of hysteretic systems is discussed. 相似文献
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图像质量是CT系统的核心指标,而空间分辨率又是图像质量评价的重要指标之一。图像的极限空间分辨率由系统的截止频率决定,通过对截止频率与系统的有效射束宽度的关系公式推导发现,工业CT系统放大倍数在不同的范围变化下CT系统有其最佳放大倍数,此时CT系统的有效射束出现最小值,极限空问分辨率达到其最大值。这些规律的发现,为检测人员在检测过程中根据自身CT系统的参数进行有效的调整,从而发挥设备的晟佳状态,使图像质量更加清晰,同时为CT系统的设计提供参考依据。 相似文献
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Fred T. Tracy 《Journal of Hydrology》1995,170(1-4):199-214
An excellent tool for checking numerical models of unsaturated flow in groundwater is analytical solutions. However, because of the highly nonlinear nature of the governing partial differential equation, only a limited number of analytical solutions are available. This paper first gives some simple 1-D solutions. Next, by use of a transformation, the nonlinear partial differential equation is converted to a linear one for a specific form of the moisture content vs. pressure head and relative hydraulic conductivity vs. pressure head curves. This allows both 2-D and 3-D solutions to be derived, which is done in this paper. Finally, computations from a finite element computer program are compared with results from one of the analytical solutions to illustrate the use of the derived equations. 相似文献
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J. Horák 《Studia Geophysica et Geodaetica》2000,44(1):26-37
The inertial manifold is a positive invariant set which exponentially attracts all the trajectories of a dissipative dynamic system. It was introduced for the purpose of studying the asymptotic behaviour of such systems. The initial infinitely dimensional dynamic system, generated by a partial differential evolution equation, can be projected on to it, in order to obtain the final system of ordinary differential equations (inertial equations). These equations then simulate the initial object. Although the inertial manifold is an object relatively simpler than the attractor (a very complicated set of non-integer dimension may be an attractor) it is more difficult to prove its existence than that of the attractor. The equation of a barotropic fluid on a rotating spherical surface is one of the examples of dissipative dynamic systems with an inertial manifold. This kindles the hope that also the equations of the dynamics of the real atmosphere will have an inertial manifold. The reduction of the sample system to this Lipschitz manifold of finite dimension thus justifies us in analysing the behaviour of the atmosphere on non-linear models of finite dimensions and few parameters, in a finite system of ordinary differential equations. 相似文献