共查询到20条相似文献，搜索用时 31 毫秒
1.
In order to search for a tool to test whether the earthquakes is reasonable for the design, a method based on multidimensional scaling (MDS) and the dynamic time warping distance (DTW) was proposed, which represents the dissimilarities of earthquake in a low dimensional space in a visualized way and uncovers hidden structure of earthquake. The analysis of record from the seismic array shows that the proposed method can be a powerful tool in detecting the correlation structure of spatial ground motion as well as verifying whether the algorithm is producing properly correlated motions in space. 相似文献
2.
Zhang Jinsong Chen Liang 《保鲜与加工》2013,(3):75-80
A three-span regular continuous RC girder highway bridge and two bins of real accelerograms were selected for incremental dynamic analysis to study the correlation of the dispersions of response spectra of earthquake ground motions and probabilistic seismic demand assessments of bridge structures. It is found that the dispersions of seismic demands are closely related to the dispersions of response spectra of selected ground motions. The rational selection of real earthquake ground motions to be rationally chosen for dynamic analysis can make the probability distribution of seismic demands in accordance with the real situation and improve the computational precision and efficiency of the probabilistic seismic demand assessment and fragility curve for performance-based earthquake engineering and seismic design of bridges based on probability theory. 相似文献
3.
Based on a spatial nonstationary model of seismic ground motion, the seismic acceleration time history are simulated by the wave superposition method. And then taking CaiYuanBa arch bridge in Chongqing as original model , this paper utilizes time history analysis method to analyze the seismic response characteristic of this type of long span arch bridge by support consistent or multi support seismic excitation .The numerical results indicate that the spatial variation of seismic ground motion have significant effect on the response of the arch bridge. Thrust of arch rib and vertical displacement, internal force of arch crown are increased greatly, but most internal forces of stiffener support are reduced. 相似文献
4.
考虑地震动的非平稳性,变化连体位置,对非对称双塔连体结构运用虚拟激励法进行非平稳随机激励下的动力可靠度研究。采用刚度退化的Bouc-Wen模型模拟塔楼各楼层的滞变特性,建立非线性化动力方程。运用混合精细积分法对每一时刻的响应进行求解,得到连体位置变化时非对称连体结构在非平稳随机激励下的时变方差。基于首次超越破坏准则与Markov假定,研究非平稳随机地震激励下连体结构的动力可靠度。运用上述理论,在8度罕遇地震作用下对某非对称双塔连体结构进行随机地震响应与动力可靠度分析。研究结果表明,地震作用下结构的层间位移响应呈现强烈的非平稳性,变化连体位置对连体结构的随机地震响应与动力可靠度将产生显著影响。 相似文献
5.
JAMES R. SCHMIDT 《Growth and change》1995,26(1):59-75
ABSTRACT Nonstationary behavior in regional economies must be recognized and categorized before activity indicators can be properly used in analyses. The nonstationary behavior of gross product by one-digit industry and personal income from all of the 50 states is examined. Tests to discriminate between stochastic and deterministic trends are pursued and the results indicate that the former dominate the latter. State-nation linkages in the presence of stochastic trends are explored and it is shown that stable, long-term relationships between nonstationary state and national outputs are rare at both the industry and aggregate levels. 相似文献
6.
The analysis of vibration response of structure with TMD is carried out under earthquake ,considering the ground-structure interaction. The varying rule of square difference of displacement of structure with the TMD on or off by changing the first inherent frequency is also presented .It has been proved by comparing and analyzing that a TMDstructure with optimum parameters can efficiently reduce the vibration of structure under strong wind and earthquake,when the main frequency of the ground motion is within the range of TMD vibration reducing frequency. 相似文献
7.
We presented herein detailed comparison between emulational and real earthquake signals. Intrinsic Mode Functions (IMF) were regarded as products of the empirical mode decomposition (EMD) during Hilbert Huang transform (HHT) processing. This could be ascribed primarily to the failure of separating the correct frequency from mixed and similar frequency components. It was difficult to remove IMF signal from the earthquake record and to obtain correct earthquake energy distribution in frequency. Furthermore, The Hilbert transform sometimes induced erroneous instantaneous frequencies. Thus, care must be taken in the application of HHT in earthquake engineering. The combination of the Hilbert transform with wavelet transform could produce better analysis of earthquake record. 相似文献
8.
The stochastic fluctuating wind pressure field acting on a large-span membrane roof consists of Gaussian and non-Gaussian regions in the sense of statistics. Simulation of this stochastic field is presented based on the zero memory nonlinearity (ZMNL) transformation method. A case study is then given to show that the stochastic wind pressure field samples generated by the proposed method can well represent the specified statistical characteristics of data from the wind tunnel experiment. After that, the wind-induced response analysis is conducted on a membrane roof structure using the Gaussian/non-Gaussian composed wind pressure field samples generated by the proposed method and the Gaussian samples by the traditional method, respectively. Results indicate that response values of some components of the structure induced by the Gaussian samples are lower than those by the Gaussian/non-Gaussian composed wind pressure samples, which means the non-Gaussian characteristics of the stochastic wind pressure should not be ignored. Meanwhile, the total gust response factors of the components caused by the wind excitation are given to meet with the requirement of the designers. 相似文献
9.
Li Yingmin Yang Jie Lai Ming 《保鲜与加工》1999,(2):5
It is necessary to study the correlation between the same peak values of two horizontal components of earthquake ground motions. The formulae for correlation of 5 peak values are regressed by using the Least Square method and the uniform LS method in which the variables are both taken to be random. Ths suggestion on the application of the formulae is given in this paper. 相似文献
10.
Huang Zongming 《保鲜与加工》1996,(3):42-48
Parameters dominating elasto- plastic earthquake response of SDOF systems,relation between ground motion amplitude and elasto- plastic response of SDOF systems are presented in this paper. 相似文献
11.
Hilbert-Huang transform(HHT) is a new method for signal analysis developed by Norden.E.Huang et al in 1998.The concepts for main contents,Empirical mode decomposition,Hilbert spectrum and marginal spectrum of Hilbert-Huang transform(HHT) are introduced.Based on the characteristics of VI's development and application,combining software and hardware,the designed method,which includes hardware,software and panel for the Virtual Signal Analyzer Based on Hilbert-Huang Transform are introduced.Based on the HHT,combined with virtual instrument technology,a Virtual Signal Analyzer is developed successfully.It has provided a new method for signal test and analysis. 相似文献
12.
MU Long hua 《保鲜与加工》2001,(5):89-92
Fault detection of the distribution systems is one of the key techniques for feeder automation. At all times, it is still very difficult for the exact detection of single phase to ground fault. First of all, the distinguishing rules of the faulted phase are presented when ground fault occurs in distribution systems. This paper analyzes the fault detection technique for single phase to ground in system with floating neutral point. Based on faulted phase's current, a method realizing ground fault protection is proposed and the algorithm model of action criterion is given out. The simulation results show that the method will be with very good selectivity to ground fault, and it can be used preferably in feeder automation. The detection method for short circuit fault is also introduced simply. 相似文献
13.
In this paper, we propose a method to solve the problems with stochastic nonlinear and point to point architecture of the wind turbines. The proposed method presents an open motion control architecture and a linearized torque control system based on power curve LUT. We reference the PLCopen motion control standard that is used to design the linearized torque and pitch systems of the wind turbines. This proposes a new methodology for the main controller design and the system integration of wind turbines. 相似文献
14.
《保鲜与加工》2002,(6):100-105
Because of the different configurations of buildings to be constructed, the arrangement of the whole-raising-scaffold used for practical construction is not always the same, which results in difference of the internal force of the whole- raising-scaffold in application. Based on the abovementioned, in this paper, the design method of the whole-raising-scaffold is investigated, a mechanical model based on the three-span continuous beam is set up, the mechanical characteristics due to the action of various load of the whole-raising-scaffold under the worst working condition is analyzed. Then the calculating method for the internal force of its main structure can be found. Combining the internal force calculated by this method, the security of the scaffold can be verified. The method introduced by this paper can be used as a general method for the scaffold design. 相似文献
15.
The inelastic dynamic response analysis program for frame-shear wall structures developed by the authors is introduced firstly, in which the multi-vertical-line-element model was adopted for shear walls and the refined single-component model was used for beams and columns in frame.By analyzing three-story structural models tested in shaking-table in a famous foreign research institute, the validity of the modeling of shear wall in the program was verified. The analytical results indicate that the inelastic dynamic responseof shear walls under random ground motion input can be predicted effectively withthe program. Finally, with the preliminary discussion of some key points in modeling of shear wall, some suggestions areput forward for further improving and refining the multi-vertical-line-element model. 相似文献
16.
A record based approach has been developed for the simulation of spatially correlated ground motion. This procedure uses autoregressive model to establish a power spectrum, and uses the multivariate linear prediction to simulate the parameter of unknown position. The random factor of earthquake is relected by Gaussian distribution random number, and the known records are subdivided into a sequence of time windows to account for its temporal variation. Compare of the simulated record and the true record show that this procedure is accurate and reasonable, and it is applicable for the design of discretely supported systems. 相似文献
17.
实际边坡动力稳定性受地震竖向与水平方向效应共同作用,传统边坡地震永久位移计算方法较少考虑竖向地震波影响,采用实际地震的竖向与水平方向加速度-时程曲线共同效应更符合工程实际。基于极限分析上限法和Newmark刚塑性滑块模型,提出一种基于实际水平向与竖向地震加速度-时程曲线的边坡永久位移计算改进方法,以3个工程边坡为例,探讨了两组具有代表性实测典型水平和竖向地震地面运动记录对边坡地震永久位移计算的影响。研究结果表明:不考虑竖向地震加速度时程曲线时,本文方法可蜕化为与前人方法兼容;不同地震波的竖向与水平地震动时程曲线的叠加效应不同,竖向地震对边坡永久位移的影响不可忽略。 相似文献
18.
Improved algorithms of modal parameter identification and its application to shaking table frame model test 
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下载免费PDF全文 Based on the data-driven stochastic subspace identification (SSI), an improved ITD method, an improved STD method and an improved complex index method are put forward. SSI has high identification accuracy, and Hankel matrix orthogonal projection calculation of data can retain all the useful information in the original data and simultaneously remove noise. The data obtained in P-matrix is taken as input for the ITD , STD and complex index methods, and then the three methods would no longer need random decrement technique or NExt method for pre-processing, thereby eliminating the error caused by the two pretreatment methods.The improved methods are applied to the modal parameter identification for structure shaking table test model by using the simulated earthquake response data from Tongji University. The recognition results further prove the correctness and feasibility of the improved methods. 相似文献
19.
The sequence of global earthquake magnitude of 7.0 and more than 7.0 is analyzed by the methods of Hurst exponent, fractal dimension D, correlation coefficient C and V-statistics and the scatter diagram and fitting trend line. The results show that this sequence is a fractional Brownian motion, mean reversion process (pink noise, anti-persistence and persistence against the state), and with a frequent reversal mutation or volatility. In the long case, the magnitude shows a very slight downward trend. Conclusion of the study can provide reference for seismic studies and safety studies. 相似文献
20.
Liquid-storage tanks, mostly used to reserve rinsing, sewerage, petroleum and chemistry liquid, are broadly applied in such industry corporations as water-supply and drainage industry, sewerage-disposal industry, petroleum industry, chemistry industry and so on. For the sake of computing preferably earthquake responding of these structures, the characteristics of their free vibration, like frequency of free vibration and corresponding oscillation-mode, have to be known beforehand. Therefore, for the liquid-storage tanks without liquid, the equations about oscillation-mode and frequency based on bending-shearing model are deduced, and at the same time, the calculation tables and chart of former three oscillation-modes are presented by using MATLAB program, and free vibration characteristics using different deformation theory in different heights are analyzed. The correctness of the result is proved by calculation example, and a theory base is provided for analyzing subsequent free vibration and earthquake responding of this type of structure. 相似文献