共查询到19条相似文献,搜索用时 156 毫秒
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为了高层建筑结构中有效地降低结构的振动反应,本文作者提出了一种附加在主结构中的安装有粘弹性阻尼器的主-辅框架结构,作者在粘弹性材料纯剪动力试验得出材料动力特性的基础上建立了数学模型,并将之应用于结构的动力分析中,采用变刚度的方法处理安装有粘弹性阻尼器的结构,安装阻尼器的框架动力试验,不仅证实阻尼器的安装可以大大减小结构的振动,也验证了数值分析方法的准确性。 相似文献
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采用整体有限元法分析土-结构动力相互作用(SSDI)下网架的动力性能。以大型有限元软件ABAQUS为平台,结合FORTRAN程序实现粘弹性动力人工边界精确施加、土体自重应力平衡及粘弹性边界条件下地震动输入,并通过算例验证有限元计算过程的有效性与合理性;建立地基土-支承体系-网架屋盖相互作用的三维整体模型,分析SSDI对网架结构动力性能影响。研究表明,SSDI使网架结构自振周期较刚性地基下延长且地基土越软周期越长,网架结构自振频率随地基土变软更密集;SSDI使基础底面峰值加速度较自由场地表峰值加速度增大5%~30%,且地基土越软增大幅度越大;SSDI效应可增大网架结构节点加速度及节点水平相对位移,且使网架结构节点水平相对位移随地基土的变软逐渐增大。 相似文献
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本文提出了一种在梁柱节点设置粘弹性阻尼器的结构减振措施。作者在进行了粘弹材料试验和选择了粘弹性材料动力特性模型的基础上,建立了安装有粘弹性阻尼器的结构的动力分析方法,并通过一根具有此种梁柱节阻尼器的长跨梁的动力试验与其计算结果的比较,证实了该减振措施的减振效果和数值分析方法的准确性 。 相似文献
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基于多源叠加粘弹性人工边界和等效线性化理论,建立了SV波斜入射下考虑场地非线性、地形效应和土-结构动力相互作用的大跨结构动力响应分析计算方法。该文首先给出了SV波斜入射下非线性场地的自由场等效线性化求解方法,然后利用ANSYS有限元软件对一座5跨连续刚构桥和场地建立了有限元模型,计算了考虑场地非线性情况下不同入射角、不同地形和不同场地刚度工况下连续刚构桥的动力响应。计算结果表明:桥墩轴力随着入射角的增大而增大,剪力则随着入射角的增大而减小;局部地形不规则程度对桥梁结构内力放大效应有所不同,地形变化越剧烈,放大效应越明显;土体刚度对考虑土-结构动力相互作用的桥梁结构动力响应有较大影响,土体越软,土-结构动力相互作用效应越明显。 相似文献
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粘弹性自由层阻尼管的有限元建模与试验研究 总被引:1,自引:1,他引:0
U型管是工业应用中的常见结构,也是振动破坏的多发部件.分析了局部黏附粘弹性沥青阻尼层U型管结构的动力特性.考虑弯曲成形过程中的厚度与截面形状变化,建立了自由层阻尼管的有限元精确模型,采用迭代法计算粘弹性结构的固有频率,进而采用模态应变能法,求得各阶模态附加的阻尼比.通过对有限元结果和试验结果的比较,验证所建立的有限元模型的正确性.最后,基于正交试验表,对阻尼层的粘贴宽度,厚度,位置等进行了试验研究,指出三种因素的对结构固有频率和阻尼比的影响,为复杂管道的减振设计提供了参考依据. 相似文献
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粘弹性层状地基的动态响应 总被引:2,自引:0,他引:2
本文建立了层状地基的力学分析模型,并从基本方程出发,推导了在动荷载作用下层状粘弹性地基的地表响应公式,方法的有效性通过与动力有限元计算结果进行对比而予以验证。 相似文献
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SUNG YI M. FOUAD AHMAD HARRY H. HILTON 《International journal for numerical methods in engineering》1997,40(10):1857-1875
Recently much attention has been paid to high-performance computing and the development of parallel computational strategies and numerical algorithms for large-scale problems. In this present study, a finite element procedure for the dynamic analyses of anisotropic viscoelastic composite shell structures by using degenerated 3-D elements has been studied on vector and coarse grained and massively parallel machines. CRAY hardware performance monitors such as Flowtrace and Perftrace tools are used to obtain performance data for subroutine program modules and specified code segments. The performances of conjugated gradient method, the Cray sparse matrix solver and the Feable solver are evaluated. SIMD and MIMD parallel implementation of the finite element algorithm for dynamic simulation of viscoelastic composite structures on the CM-5 is also presented. The performance studies have been conducted in order to evaluate efficiency of the numerical algorithm on this architecture versus vector processing CRAY systems. Parametric studies on the CM-5 as well as the CRAY system and benchmarks for various problem sizes are shown. The second study is to evaluate how effectively the finite element procedures for viscoelastic composite structures can be solved in the Single Instruction Multiple Data (SIMD) parallel environment. CM-FORTRAN is used. A conjugate gradient method is employed for the solution of systems. In the third study, we propose to implement the finite element algorithm in a scalable distributed parallel environment using a generic message passing library such as PVM. The code is portable to a range of current and future parallel machines. We also introduced the domain decomposition scheme to reduce the communication time. The parallel scalability of the dynamic viscoelastic finite element algorithm in data parallel and scalable distributed parallel environments is also discussed. © 1997 by John Wiley & Sons, Ltd. 相似文献
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该文采用一种由Mooney-Rivlin模型和多个Maxwell模型叠加组成的非线性粘弹性本构模型,用于计算橡胶隔振器的高频动态特性。该文给出了在时域和频域范围内拟合本构模型中粘弹性参数的方法,利用拟合得到的本构模型参数,对某款橡胶悬置跨点动态特性进行计算,并与实验结果进行对比。该文还建立了橡胶隔振器等效力学模型,分析了原点动刚度和跨点动刚度的区别,分析表明:使用跨点动态特性测试法可消除测试中附加惯性力的影响,适用于橡胶隔振器高频动特性的测试;同时,该文搭建了橡胶隔振器有限元模型,分别用于分析其跨点动刚度与原点动刚度,并将分析结果与实验结果进行对比,分析结果验证了有限元模型和力学模型的正确性。除此之外,该文还分析对比了时域(松弛、蠕变)和频域(简谐动态试验)拟合粘弹性参数方法的优缺点。 相似文献
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Vladimir V. Mokeyev 《International journal for numerical methods in engineering》2001,50(9):2271-2282
A generalized complex eigenvector method which can be used to a linear dynamic analysis of viscoelastic structures is described. Here dynamic analysis is understood as transient analysis and frequency response analysis. The generalized complex eigenvector method is based on finite element discretization of structure, approximation of viscoelastic properties by differential operators and mode superposition technique. Coefficients of differential operator are defined from the condition of best coincidence of complex characteristic of viscoelastic material and complex characteristic of differential operator in preset frequency range. Advantage of this method is that it allows to take into account the real changes of the viscoelastic property in frequency range. Also, the generalized complex eigenvector method permit to describe a viscoelastic properties by two functions (complex Young's modulus, complex Poisson's ratio). The method is verified with the help of comparing with solutions obtained by complex modulus method. An influence of viscoelastic Poisson's ratio on transient and frequency responses of structure is demonstrated. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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粘弹性材料具有良好的阻尼性能,在工程振动与噪声处理上的应用非常广泛。利用粘弹性材料进行阻尼结构设计并预测其动力学特性,需要知道准确的动力学参数。回顾粘弹性材料动力学参数测试的经典方法,并着重介绍共振法测试技术。研究共振法测试中细棒的动力学响应与动力学参数间的关系,在此基础上,基于共振法测试数据和有限元仿真,提出一种反演粘弹性材料动力学参数的新方法。首先根据幅值比反演出损耗因子,再根据共振频率反演出储能模量。通过具体算例验证可知,反演得出的动力学参数的相对误差均在4 % 以内,该反演方法不仅结果收敛、准确可靠且反演速度快,为在连续频率范围内的动力学参数反演奠定基础。 相似文献
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Tzer-Ming Chen 《International journal for numerical methods in engineering》1995,38(3):509-522
The quasi-static and dynamic responses of a linear viscoelastic beam are solved numerically by using the hybrid Laplace transform/finite element method. In the analysis, the Timoshenko beam theory, which includes the transverse shear and rotatory inertia effect and conventional beam theory, are used to solve this problem. The temperature field is assumed to be constant and homogeneous and that the relaxation modulus has the form of the Prony series. In the hybrid method, the Laplace transform with respect to time is applied to the coupled equations and the finite element model is developed by applying Hamilton's variational principle without any integral transformation. The numerical results of quasi-static and dynamic responses for the models of Maxwell fluid and three parameter solid types are presented and discussed. 相似文献
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Viscoelastic sandwich structure is widely used in sealing, vibration damping and noise reduction of mechanical equipment. However, viscoelastic material may appear aging phenomena in the process of long time storage, transportation and usage. The aging of viscoelastic material will result in the service performance degradation of viscoelastic sandwich structure, thus affect the performance and safe for use of whole mechanical equipment. Therefore, it is greatly required of the engineering practice to research the aging state recognition method of viscoelastic sandwich structure. In this paper, the experimental device of typical viscoelastic sandwich structure is designed. The hot oxygen accelerated aging experiment of viscoelastic material is accomplished, and the specimens with different aging degrees are obtained. The mechanical property test of viscoelastic material is implemented, and the performance indexes under different aging degrees are obtained. By the 3D modeling-importing-preprocessing method, the finite element model of viscoelastic sandwich structure is established. By importing the different parameters of viscoelastic material, the purpose of equivalent models with different aging states is reached. The finite element analysis of viscoelastic sandwich structure under different aging states is carried out, and the corresponding relations between aging state changes and natural frequency changes are built. Through impulse excitation experiment, the effectiveness of finite element model is verified. The research results show that the established finite element model of viscoelastic sandwich structure can reflect the structural aging state characteristics and its change, and can provide theoretical foundation and prior knowledge for the structural aging recognition. 相似文献
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Parametric resonance of polar orthotropic sandwich annular plates with a viscoelastic core layer subjected to a periodic uniform radial stress is studied by the finite element method. The axisymmetric discrete layer annular element and Hamilton's principle are employed to derive the finite element equations of motion for a sandwich plate including the transverse shear effect. The viscoelastic material in the core layer is assumed to be incompressible, and the extensional and shear moduli are described by complex quantities. The regions of dynamic instability are determined by Bolotin's method. The effects of various parameters on the dynamic instability regions are investigated. 相似文献