Accurate Wind-Induced Response Analysis of Long-Span Structure Based on Quick Modal Response Estimate for Mode Selection

2011 ◽  
Vol 243-249 ◽  
pp. 844-853
Author(s):  
Li Gang Zhang ◽  
Wen Juan Lou ◽  
Ming Feng Huang
Keyword(s):  
Wind Loads ◽  
Induced Response ◽  
Response Analysis ◽  
Frequency Domain Method ◽  
Superposition Method ◽  
Relative Significance ◽  
Similarity Factor ◽  
Long Span ◽  
Mode Superposition Method ◽  
Modal Response

By the combination of POD method and mode superposition method, the eigenvector similarity factor is introduced on the representation of the similarity between the load spacial distribution and the structural mode. Meanwhile, the eigenvalue got from the wind pressure field decomposition indicates the relative ratio of the energy associated with the corresponding load spacial distribution to the total of the wind load energy. It is proved that the eigenvector similarity factor and the eigenvalues are two of most important factors when measuring the relative significance of each modal response. So the quick estimates of the modal responses are provided, which predominates in picking structural modes to obtain wind-induced dynamic response of long-span roof structure with frequency-domain method. Then, by arranging the estimative response of each mode in reduced-order and truncating higher modes to expedite computations, the accurate wind-induced response is calculated by ACQC method, which has taken into account the partial correlation of wind loads and the quad-spectra (imaginary parts of XPSD) of the generalized wind loads. Finally, utilizing the rigid model wind tunnel test data of some large railway station platform, the effectiveness of the scheme proposed is verified.

Seven Mega Floor MSCSS Modal Analysis

2013 ◽  
Vol 353-356 ◽  
pp. 2210-2215
Author(s):  
Jun Jun Wang ◽  
Lu Lu Yi
Keyword(s):  
Modal Analysis ◽  
Response Spectrum ◽  
Time History ◽  
Response Analysis ◽  
Superposition Method ◽  
Response Spectrum Analysis ◽  
Mode Superposition Method ◽  
History Analysis ◽  
Basic Performance ◽  
Dynamic Time

Modal analysis is also known as dynamic analysis for mode-superposition method. In the seismic response analysis of linear structural systems, it is one of the most commonly used and the most effective ways. Through the modal analysis of building structure, we can get some basic performance parameters of the structure. These parameters can help us make qualitative judgments for the respond of a structure first, and can help us judge whether they meet demands for conceptual design. Modal analysis is also the basis of other dynamic response analysis, including dynamic time history analysis and response spectrum analysis.

Objective-based equivalent static wind loads for long-span bridges

2019 ◽  
Author(s):  
Zachary J. Taylor ◽  
Pierre-Olivier Dallaire ◽  
Stoyan T. Stoyanoff
Keyword(s):  
Time Domain ◽  
Experimental Testing ◽  
Wind Loads ◽  
Response Analysis ◽  
Long Span Bridges ◽  
Buffeting Response ◽  
Long Span ◽  
Equivalent Static Wind Loads ◽  
The Time Domain ◽  
Key Aspects

<p>The process to arrive at design wind loads for long-span bridges involves experimental testing and analytical methods. Time domain simulations are becoming increasingly common and many available studies demonstrate results of buffeting response analysis in the time domain. However, there is significantly more to the process than the response analysis to derive wind loads that can be applied practically for design. The current study focuses on two key aspects required to derive design wind loads: prediction of the peak modal deflection and derivation of modal combination coefficients using objective functions.</p>

Dynamic Buckling Analysis of Axi-Symmetric Shells

Volume 2 ◽  
2004 ◽  
Author(s):  
Yaghob Gholipour
Keyword(s):  
Natural Frequency ◽  
Stiffness Matrix ◽  
Memory Management ◽  
Shell Element ◽  
Buckling Analysis ◽  
Dynamic Buckling ◽  
Mode Shapes ◽  
Response Analysis ◽  
Superposition Method ◽  
Mode Superposition Method

In the field of dynamic buckling analysis of shell structures, the effect of vibration on buckling load and the effect of axial loads on vibration are very interesting phenomena. In this work the finite element method has been applied for dynamic buckling analysis of axi-symmetric shell. The degenerated axi-symmetric shell element and subspace iteration technique has been used to carry out the analysis. The stiffness matrix is stored in band form to have efficient memory management and the 3 × 3 gauss quadrature has been used for calculation of element stiffness matrix and consistent load vector. An attempt is made to study the effect of static in-plane edge loads on the fundamental frequency of axi-symmetric shells. The effect of vibration at a prescribed frequency on the buckling behavior of shell is also investigated. From the limited analysis carried out, it is found that the presence of static in-plane edge loads considerably affects the natural frequency and hence necessitates the evaluation of appropriate natural frequency and mode shapes for use in realistically carrying out the dynamic response analysis of structures subjected to forced vibration by mode superposition method.

Dominant mode selection and modal coupling analysis for wind-induced response of long-span roofs

2016 ◽  
Vol 20 (4) ◽  
pp. 616-628
Author(s):  
Yuxue Li ◽  
Kai Shi ◽  
Qingshan Yang ◽  
Yuji Tian
Keyword(s):  
Mode Selection ◽  
Structural Response ◽  
Combination Method ◽  
Induced Response ◽  
Response Analysis ◽  
Square Root ◽  
Coupling Analysis ◽  
Modal Strain Energy ◽  
Long Span ◽  
Modal Coupling

Mode selection and modal coupling analysis are important to estimate wind-induced structural response of long-span roof structures. This article presents a framework for predicting wind-induced structural response of long-span roof structures based on modal analysis. This framework first identifies the dominant modes according to the correlation between the mode shape and the wind load spatial distribution on the structure as well as a proposed “modal participation coefficient.” Second, the concept of modal strain energy is introduced and a modal coupling coefficient is defined, based on which the dominant coupling modes are determined. A modified square root of the sum of the squares methodology is then developed to account for the modal coupling effects of the background and the resonant response components. The total responses can be obtained by combining the contributions of the dominant coupling modes and the square root of the sum of the squares results from the dominant modes. This avoids the use of the computation expensive complete quadratic combination method. Finally, an illustrative example of wind-induced response analysis of the China National Stadium roof structure is provided to demonstrate the effectiveness of the proposed framework.

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