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为研究地基土-两层偏心结构相互作用体系的地震反应,本文对平扭耦联问题进行了参数分析。利用拉格朗日能量法建立了土-两层偏心结构相互作用体系平扭耦联运动方程,求得频域内解析解,并编制MATLAB程序,确定了影响两层偏心结构平扭耦联的主要参数,详细分析了扭平频率比Ω、偏心率B、偏心楼层位置和地基土特性等参数对相互作用体系弹性地震反应的影响规律,以及对平扭耦联程度的影响状况,得到了一些与刚基上偏心结构平扭耦联反应不同的参数影响规律,为工程计算和设计提供参考。 相似文献
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本文对多层基础滑移隔震结构进行了水平双向地震作用下的平-扭耦联地震反应分析,研究了上部结构偏心和上部结构抗扭刚度对结构地震反应的影响,分析表明上部结构质量偏心较上部结构刚度偏心对基础滑移隔震结构地震反应的影响更大,因而应减小上部结构质量中心与隔震层质量中心和刚度中心的偏心距,以减小结构的扭转反应;当上部结构的质量偏心距较小时,其对基础滑移隔震结构的地震反应也有一定程度的影响,在结构设计应予以考虑;上部结构的抗扭刚度对上部结构的地震反应影响较大,增大上部结构的抗扭刚度可有效减小上部结构的地震反应,但上部结构的抗扭刚度对隔震层的地震反应影响较小。 相似文献
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土-结构动力相互作用对隔震结构影响的模态分析方法 总被引:6,自引:1,他引:5
本文将频域模态分析方法推广到土-结构动力相互作用对基础事震结构的影响分析下。基于上部结构固定时具有正则型的假设下,推导了地震激励作用下,土-结构动力相互作用对基础隔震结构影响的频域模态分析的步骤。算例表明,采用低阶模态进行计算,得到较高精度的分析结果的同时,可以有效地减少计算时间。 相似文献
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针对土-结构动力相互作用的实时耦联动力试验(SSI-RTDHT),以单自由度上部结构体系为例,建立了考虑振动台时滞及其补偿的数学模型;然后采用基于Padé 展开逼近时滞项的根轨迹方法研究其稳定性;最后利用数值仿真验证了理论分析得出的稳定条件.研究结果表明:时滞明显地改变了系统固有模态的动力特性,并使得SSI-RTDHT 成为一个条件稳定系统;稳定性随时滞和上部结构频率的增大而降低,随地基特征频率的增大而提高;上部结构阻尼比对稳定性影响不大.三阶多项式补偿会明显降低试验体系的稳定性,但可以改善固有模态的性能. 相似文献
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通过采用自制的传感器布设装置,把加速度传感器放入钢管桩内,采用子结构技术把结构分为两个子结构,对打入实际土层的钢管桩进行了横向位移模态的测试,同时,对槽墩也进行了模态测试实验。实验结果表明槽墩与桩有着相同的自振频率,并且组合形成了桩-槽墩系统振动模态。采用大型通用有限元软件ABAQUS进行了桩-槽墩系统的自振特性分析,有限元计算中对桩-土相互作用采用了简化模拟的方法,计算结果与试验结果基本吻合;并同刚性地基模型进行比较,其结果显示,在渡槽的设计中不能忽略桩-土相互的作用。 相似文献
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分析、探讨线性-非线性混合约束模态综合法用于土-结构相互作用的动力分析实施方法。据结构存在局部非线性特性,提出对整体结构划分为若干个线性、非线性子结构,对线性子结构只需一步提取特性矩阵并进行方程降阶,而对非线性子结构则逐步提取降阶后的等效特性矩阵。通过组装各子结构达到对整体结构特性矩阵的降阶处理。对非线性子结构凭借在小段时间 内利用分段等效线性化手段,通过ANSYS二次开发工具UPFs编辑写成可执行程序文件,并与MATLAB联立计算,实现特性矩阵提取。结果表明,该方法求得结构的各阶频率和动态响应时程曲线与ANSYS直接计算吻合良好。可逐步提取等效弹塑性特性矩阵,为采用变化的特性矩阵对结构进入塑性阶段深层次分析研究提供有效方法。 相似文献
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提出了一个利用模态分解和傅里叶变换求解不对称结构扭转耦合动力响应的土-结构相互作用分析的实用简化方法,从而不仅使矩阵计算大大简化,计算结果具有较高准确性。数值参数分析表明当地基土为软土,尤其是地基土剪切波波速低于1000m/s时,基础水平位移和摇摆幅度分别随结构质量与基础质量之比和结构高度与回转半径之比的增加而显著增大。对于地基土不是硬土,而且具有一定的高度和刚度偏心距的结构,必须考虑扭转耦合的土一结构动力相互作用的影响。 相似文献
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通过振动台试验来验证调液阻尼器对偏心结构扭转耦联振动反应的减振效果及理论分析的正确性。设计了一个二层的单向偏心钢结构模型,在结构的顶层放置一个调液柱型阻尼器(TLCD)和一个环形调液阻尼器(CTLCD)并对其参数进行优化设计,在振动台上,分别对结构无控时的反应和设置调液阻尼器后的反应进行试验研究。通过分析结构模型在地震波作用下的加速度和位移响应,结果表明,调液阻尼器能有效抑制结构的在地震作用下的扭转耦联振动,而且同时设置TLCD和CTLCD的减振效果要好于单独采用TLCD或CTLCD时的减振效果。 相似文献
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Rockstuhl C Salt MG Herzig HP 《Journal of the Optical Society of America. A, Optics, image science, and vision》2003,20(10):1969-1973
The boundary-element method is applied to the interaction of light with resonant metallic nanoparticles. At a certain wavelength, excitation of a surface plasmon takes place, which leads to a resonantly enhanced near-field amplitude and a large scattering cross section. The resonance wavelength for different scatterer geometries is determined. Alteration of the scattering properties in the presence of other metallic nanoparticles is discussed. To treat this problem, a novel formulation of the boundary-element method is presented that solves the interaction problem for all the coupled particles. 相似文献
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《Materials Science & Technology》2013,29(9):985-994
AbstractAn analytical model is constructed to determine the effect of solute–solute interactions on the growth restriction parameter Q. Relevant to analysing the as cast grain size in alloys inoculated with potent nuclei, the value of Q describes the effect of solute partitioning on the growth rates of solid in the liquid. The model is constructed for highly simplified aluminium based ternary systems with two solutes of identical partitioning behaviour. The regular solution coefficient between the two solutes is varied, and its effect on Q is determined. The sign of the change of Q is dependent on the partition coefficient of the solutes: four distinct regimes are found, for k<½, ½<K<1, 1<k<2, and k>2. 相似文献
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提出了分析非同轴刚度偏心结构风振响应的基本框架。第一,建立了两层6个自由度(6DOFs)非同轴刚度偏心结构的动力方程。第二,将建立的动力方程扩展至多层(大于两层)非同轴刚度偏心结构情况。第三,基于顺风向、横风向及扭转风荷载功率谱,并考虑横风向与扭转风荷载间相关性及模态响应间耦合,建立了非同轴刚度偏心结构风致平-扭耦合响应的分析方法。最后,以15DOFs结构为例,通过设置结构不同刚度偏心,数值研究了非同轴刚度偏心对结构风致平-扭耦合响应的影响。 相似文献
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《Engineering Analysis with Boundary Elements》2000,24(2):201-206
In this paper, a boundary element method for analyzing building foundation plates is presented. The shear deformation is considered using the Reissner plate theory. The Winkler model is used to model the behavior of the soil. Only the boundary of the plate needs to be discretized. Two practical applications are solved and the results are compared to alternative solutions of different methods, such as, finite difference, finite element and 3D boundary element methods. 相似文献
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Alexis Tello Ramon Codina 《International journal for numerical methods in engineering》2021,122(1):53-81
The standard Fluid-Structure Interaction (fsi ) coupling, that uses as unknowns velocity and pressure for the fluid and displacements for the solid, is compared against two novel types of coupling, the first one a three-field coupling (velocity-pressure-stress/displacement-pressure-stress) introduced by the authors in a recent work, and a two-field coupling (velocity-pressure/displacement-pressure) introduced in this paper, in this way completing our set of Field to Field (f2f ) equations, all stabilized by means of the Variational Multi-Scale (vms ) method using dynamic and orthogonal subscales. The solid two-field fsi coupling formulation is benchmarked statically and dynamically. Proper Orthogonal Decomposition (pod ) is applied to all three fsi formulations to obtain reduced basis and asses their performance in a reduced space. Numerical tests are shown comparing all three formulations. By correctly resolving the Cauchy stress tensor, the three-field fsi coupling proves to provide more accurate results in both Full Order Model (fom ) and Reduced Order Model (rom ) spaces than its counterparts for a similar number of degrees of freedom, making it a reliable formulation. f2f pairing appears to be beneficial, providing more accurate results in all cases shown; mixed pairing with a three-field formulation in the solid appears to produce very precise results as well. 相似文献
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直升机纵、横向耦合动力学模型的参数辨识方法研究 总被引:1,自引:1,他引:1
提出了一种提高直升机纵、横向全耦合动力学模型辨识精度的方法,该方法根据BO-105直升机的频率飞行试验数据,通过构建多步辨识算法和相应的优化指标函数,解决了直升机纵、横向全耦合动力学模型中辨识参数多,灵敏度差异大,耦合严重等造成的信息矩阵病态问题,得到的直升机纵、横向全耦合动力学模型与飞行试验数据相比具有良好的一致性. 相似文献
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Wenchang Zhao Leilei Chen Haibo Chen Steffen Marburg 《International journal for numerical methods in engineering》2019,119(5):404-431
This paper presents an efficient topology optimization procedure for exterior acoustic-structure interaction problems, in which the coupled systems are formulated by the boundary element method (BEM) and the finite element method (FEM). So far, the topology optimization based on the coupled FEM-BEM still faces several issues needed to be addressed, especially the efficient design sensitivity analysis for the coupled systems. In this work, we contribute to these issues in two main aspects. Firstly, the adjoint variable method (AVM) formulations are derived for sensitivity analysis of arbitrary objective function, and the feedback coupling between the structural and acoustic domains are taken into consideration in the sensitivity analysis. Secondly, in addition to the application of fast multipole method (FMM) in the acoustic BEM response analysis, the FMM is now updated to adapt to the arising different multiplications in the AVM equations. These accelerations save considerable computing time and memory. Numerical tests show that the developed approach permits its application to large-scale problems. Finally, some basic observations for the optimized designs are drawn from the numerical investigations. 相似文献