共查询到19条相似文献，搜索用时 140 毫秒
1.
《地震工程与工程振动》2020,(4)
讨论了指数阻尼体系地震反应的振型分解方法,基于复模态叠加法与状态空间法给出了地震作用下的动力反应计算的实数形式一般解答;同时,为了方便抗震设计计算,以上述实数形式一般解答为基础,推导了指数阻尼系统以反应谱表示的地震作用计算公式,从而使指数阻尼系统的抗震设计与一般黏滞阻尼系统的抗震设计的过程相吻合;最后基于Matlab平台以两个案例分别验证了阻尼矩阵非奇异与部分奇异的情况下计算方法的正确性与有效性,并与常用时程积分方法计算结果对比,说明可以满足工程计算的需要。 相似文献
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土-结构相互作用地震反应的非经典振型分解反应谱方法 总被引：2，自引：0，他引：2
土-结构联合动力体系是非正交阻尼系统,本文建立了这种非正交阻尼系统地震反应的非经典振型分解反应谱方法,并提出了各非经典振型谱反应的组合公式。这种反应谱方法包含两个反应谱——实部反应谱和虚部反应谱。当假定地震加速度为具有平缓的功率谱平稳随机过程时,上述两个反应谱近似相等。对EL Centro(1940)和天津(1976)地震记录的计算也表明了这一点。对实际高层建筑和高耸结构的计算表明,该法计算简便,易为实际工程抗震分析所应用。 这种方法适用于诸如流体-结构、流体-土-结构以及不同性质材料组成的组合结构等任何非正交阻尼系统的地震反应分析。 相似文献
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基于复振型分解的多自由度非线性体系动力可靠性研究 总被引：1，自引：0，他引：1
提出了基于复模态理论的多自由度非线性体系动力可靠性分析方法。该方法首先采用等效线性化的方法处理体系的非线性问题,然后采用复模态分析处理非经典的等效线性阻尼矩阵,将具有非经典阻尼的等效多自由度线性体系按复振型分解,将多自由度体系的随机反应分解为一系列一阶体系的复模态反应,从而求得体系的随机反应,最后进行体系的动力可靠度计算。通过算例验证,表明该方法概念明确、思路清晰,为一般多自由度非线性体系提供了一个普遍适用的动力可靠性分析方法。 相似文献
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目前用于结构抗震设计的反应谱仅能反映峰值反应,无法体现反应值随时间的变化。文中提出一种弹性能量半径演化谱,可反映线性单自由度体系弹性能量(即动能与弹性势能之和)随地震持时的变化,且其峰值近似等于结构峰值位移。文中给出了利用地震动演化功率谱得到该演化谱的方法并进一步发展了一种计算线性多自由度体系地震位移反应的新方法。通过两座框架结构的地震反应计算,将新方法与传统振型组合法及时程分析法的计算结果进行对比,发现对于振型稀疏结构,新方法计算结果与SRSS法接近;而对于振型密集结构,新方法计算结果较CQC法更精确,且避免了CQC法相关系数的复杂计算。 相似文献
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耗能减振结构的抗震设计方法 总被引：54，自引：7，他引：47
本文基于国内外耗能减振装置的性能试验和耗能减振结构的计算研究并结合我国正在修订的建筑结构抗震规范。提出了耗能减震结构抗震设计的统一方法。首先,提出了速度相关型线性耗能器和滞变型耗能器等效阻尼和刚度的计算方法;其次,通过大量的计算比较,研究了耗能减振结构非交阻尼阵强行解耦的精度和实际应用的可行性,提出了在结构地震反应分析了振型分解反应谱法中耗能器可统一归结为结构附加振型阻尼比的方法;第三,通过耗能减 相似文献
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复阻尼地震反应谱的计算方法及其它 总被引：13，自引：2，他引：11
本文阐述了为什么要研究复阻尼地震反应谱问题,并给出了复阻尼地震反应谱计算的精确方法．实例计算结果表明,复阻尼反应港与常用的粘性阻尼反应谱之间存在着相当大的差异．文中还简述了复阻尼系统运动方程的建立方法。 相似文献
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本文采用子空间迭代法分析了单层膜型网壳结构的自振特性;推导了大跨空间结构几何非线性地震响应时程分析的计算过程,编制相应的计算程序,用振型分解反应谱法与时程法进行了结构地震响应特性分析。研究表明:膜型网壳结构的抗震性能比较好;用反应谱法分析时,水平地震作用下截断振型取15、竖向地震作用下取60可满足工程设计要求;用反应谱法计算结构竖向地震响应是安全可靠的,但进行水平地震响应分析时,最终还需用时程法进行验算。 相似文献
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大跨度钢桁架转换层结构的竖向地震反应分析 总被引：1，自引：1，他引：0
对某一带钢桁架转换层的复杂高层结构进行了有限元建模,分别采用振型分解反应谱法、时程分析法和《建筑抗震设计规范》(GB50011-2001)的设计反应谱法对大跨高位钢桁架转换层结构的竖向地震响应进行了分析.对采用振型分解反应谱法计算此类结构响应时所要选取的振型数及振型组合方法进行了探讨,并对规范采用10％的重力荷载代表值... 相似文献
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结构动力灵敏度分析中的几个问题 总被引：3，自引：0，他引：3
结构动力灵敏度分析是进行抗震结构优化设计和考虑参数不确定性进行动力可靠性分析的基本步骤。本文就结构动力分析中几个常用的计算过程进行灵敏度分析研究,给出了Choleskey分解矩阵及其它常用数学变换的灵敏度计算表达,分析了振型灵敏度的传递作用,指出对于一般的剪切型结构可以不考虑振型及振型参与系数的灵敏度,从而使问题大为简化。本文还讨论了结构动力反应与各基本参数的灵敏度之间的关系,提出了直接通过结构地震反应得到灵敏度谱的设想。作者认为,通过大量的统计分析可以得到工程上实用的地震反应灵敏度谱。 相似文献
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In the complex mode superposition method, the equations of motion for non-classically damped multiple-degree-of-freedom （MDOF） discrete systems can be transferred into a combination of some generalized SDOF complex oscillators. Based on the state space theory, a precise recurrence relationship for these complex oscillators is set up; then a delicate general solution of non-classically damped MDOF systems, completely in real value form, is presented in this paper. In the proposed method, no calculation of the matrix exponential function is needed and the algorithm is unconditionally stable. A numerical example is given to demonstrate the validity and efficiency of the proposed method. 相似文献
12.
The response-spectrum mode superposition method is widely used for seismic response analyses of linear systems. In using this method, the complete quadratic combination （CQC） is adopted for classically damped linear systems and the complex complete quadratic combination （CCQC） formula is adopted for non-classically damped linear systems. However, in both cases, the calculation of seismic response analyses is very time consuming. In this paper, the variation of the modal correlation coefficients of displacement, velocity and displacement-velocity with frequency and damping ratios of two modes of interest are studied, Moreover, the calculation errors generated by using CQC and square-root-of-the-sum-of-thesquares （SRSS） methods （or CCQC and CSRSS methods） for different damping combinations are compared. In these analyses, some boundary lines for classically and non-classically damped systems are plotted to distinguish the allowed minimum frequency ratio at given geometric mean of the damping ratios of both modes if their relativity is neglected. Furthermore, the simplified method, which is a special mode quadratic combination method considering only relativity of adjacent modes in CQC method and named simplified CQC or partial quadratic combination （PQC） method for classically damped linear system, is proposed to improve computational efficiency, and the criterion for determination of how many correlated modes should be adopted is proposed. Similarly, the simplified CCQC or complex partial quadratic combination （CPQC） method for the non-classically damped linear system and the corresponding criterion are also deduced. Finally, a numerical example is given to illustrate the applicability, computational accuracy and efficiency of the PQC and CPQC methods. 相似文献
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This paper considers a solution method for viscously damped linear structural systems which are subjected to transient loading. The equations of motion of such systems are written in a first-order form. A solution subspace is generated using the damped dynamic matrix and the static deflection from the first-order form of the equations of motion. Two convenient bases, Lanczos vectors and Ritz vectors, are constructed from this subspace. An approximate solution is then obtained by superposition of the Lanczos vectors or the Ritz vectors. In contrast to the traditional mode superposition method using complex eigenvectors, the Lanczos vectors or the Ritz vectors are less expensive to generate than the complex eigenvectors, yet yield comparable accuracy. In addition, there is no need for a static correction since the static deflection is already contained in our solution subspace. Numerical examples are presented to show the potential of using the Ritz vectors to compute responses of damped dynamic systems. 相似文献
14.
Coupling adjacent buildings using discrete viscoelastic dampers for control of response to low and moderate seismic events is investigated in this paper. The complex modal superposition method is first used to determine dynamic characteristics, mainly modal damping ratio and modal frequency, of damper-linked linear adjacent buildings for practical use. Random seismic response of linear adjacent buildings linked by dampers is then determined by a combination of the complex modal superposition method and the pseudo-excitation method. This combined method can effectively and accurately determine random seismic response of non-classically damped systems in the frequency domain. Parametric studies are finally performed to identify optimal parameters of viscoelastic dampers for achieving the maximum modal damping ratio or the maximum response reduction of adjacent buildings. It is demonstrated that using discrete viscoelastic dampers of proper parameters to link adjacent buildings can reduce random seismic responses significantly. Copyright © 1999 John Wiley & Sons Ltd. 相似文献
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In stochastic analysis the knowledge of cross-correlation coefficients is required in order to combine the response of the modal Single-Degree-Of-Freedom (SDOF) oscillators for obtaining the nodal response. Moreover these coefficients play a fundamental role in the seismic analysis of structures when the response spectrum method is used. In fact they are used in some modal combination rules in order to obtain the maximum response quantities starting from the modal maxima. Herein a method for the evaluation of the cross-correlation coefficients for non-classically damped systems is presented. It is defined in the time domain instead of the frequency domain as usually encountered in the literature. Although non-classically damped structures possess complex eigenproperties, the great advantage in using this approach lies in the fact that the evaluation of these coefficients does not require complex quantities. Moreover a further particularization of the presented method allows a simple application of the spectrum analysis requiring only one response spectrum for an assigned damping ratio. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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S. T. Mau 《地震工程与结构动力学》1988,16(6):931-942
For structures with non-proportional damping, complex eigenvectors or mode shapes must be used in order to decoe the equations of motion. The resulting equations can then be solved in a systematic way. The necessity of solvie complex eigenvalue problem of a large system remains an obstacle for the practical application of the method. This stres utilizes the fact that in practice only a small number of the complex modes are needed. Therefore, these complex modes be approximated by a linear combination of a small number of the undamped modes, which can be obtained by established methods with less cost. An additional eigenvalue problem is then solved in a subspace with a much sm dimension to provide the best combination coefficient for each complex mode. The method of solution for the decoue equations is then carried over, using the approximate complex modes expressed in undamped mode shapes, to resue simple formulas for the time- and frequency-domain solution. Thus, an efficient modal superposition method is develoe for non-proportionally damped systems. The accuracy of this approximate method is studied through an example. Comparing the frequency response result using the approximate method with that using the exact complex modes, found that the error is negligible. 相似文献
18.
A new response-spectrum mode superposition method, entirely in real value form, is developed to analyze the maximum structural response under earthquake ground motion for generally damped linear systems with repeated eigenvalues and defective eigenvectors. This algorithm has clear physical concepts and is similar to the complex complete quadratic combination (CCQC) method previously established. Since it can consider the effect of repeated eigenvalues, it is called the CCQC-R method, in which the correlation coefficients of high-order modal responses are enclosed in addition to the correlation coefficients in the normal CCQC method. As a result, the formulas for calculating the correlation coefficients of high-order modal responses are deduced in this study, including displacement, velocity and velocity-displacement correlation coefficients. Furthermore, the relationship between high-order displacement and velocity covariance is derived to make the CCQC-R algorithm only relevant to the high-order displacement response spectrum. Finally, a practical step-by-step integration procedure for calculating high-order displacement response spectrum is obtained by changing the earthquake ground motion input, which is evaluated by comparing it to the theory solution under the sine-wave input. The method derived here is suitable for generally linear systems with classical or non-classical damping. 相似文献
19.
Non-proportional damping may be defined as a form of linear viscous damping which introduces coupling between the undamped modal co-ordinate equations of motion. The standard mode superposition method of earthquake response analysis therefore cannot be employed with non-proportionally damped structures. In this paper, several methods for analysing the dynamic response of non-proportional damped structures are outlined. It is concluded that the most efficient procedure is to express the response in terms of a truncated set of undamped modal coordinates and to integrate directly the resulting coupled equations. The effectiveness of the method is demonstrated by a numerical example. 相似文献