scholarly journals Inelastic Responses of Two-Way Asymmetric-Plan Structures under Bidirectional Ground Excitations—Part I: Modal Parameters

2012 ◽  
Vol 28 (1) ◽  
pp. 105-139 ◽  
Author(s):  
Jui-Liang Lin ◽  
Keh-Chyuan Tsai ◽  
Wen-Chia Yang
Keyword(s):  
Vibration Mode ◽  
Response Spectra ◽  
Modal Parameters ◽  
Building Structure ◽  
Elastic Parameters ◽  
Modal System ◽  
Inelastic Responses ◽  
Three Degree Of Freedom ◽  
Modal Systems ◽  
Variation Trends

It has been found that any one vibration “mode” of an inelastic multistory two-way asymmetrical building structure can be represented by a three-degree-of-freedom (3DOF) modal system representing two modal translations and one modal rotation. This study introduces the inelastic response spectra constructed from the inelastic 3DOF modal systems, which is specifically useful for multistory two-way asymmetric-plan buildings subjected to bidirectional ground excitations. These spectra for asymmetrical structures (SAS) provide the three-component inelastic peak modal responses of multistory two-way asymmetric-plan buildings subjected to bidirectional ground excitations. In order to construct the SAS, the independent elastic parameters of the 3DOF modal systems were identified and the inelastic 3DOF modal parameters versus the strength ratio relationships were established. The parametric study of the 3DOF modal parameters showed the ranges and the variation trends of these parameters. Two example buildings are analyzed to verify the effectiveness of the above-mentioned investigations.

scholarly journals Inelastic Responses of Two-Way Asymmetric-Plan Structures under Bidirectional Ground Excitations—Part II: Response Spectra

2012 ◽  
Vol 28 (1) ◽  
pp. 141-157 ◽  
Author(s):  
Jui-Liang Lin ◽  
Wen-Chia Yang ◽  
Keh-Chyuan Tsai
Keyword(s):  
Vibration Mode ◽  
Response Spectra ◽  
Companion Paper ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Ductility Demand ◽  
Inelastic Responses ◽  
Constant Strength ◽  
Three Degree Of Freedom ◽  
Modal Systems

Based on the studies in the companion paper, this paper presents the inelastic response spectra for asymmetrical structures (SAS) under bidirectional ground excitations. Firstly, the constant-strength SAS were constructed and compared with the corresponding conventional constant-strength response spectra. It was found that the modal ductility demands of an asymmetric-plan structure could be significantly overestimated from the conventional constant-strength response spectra as the nonlinear “modal” rotation and translations may not be proportional. Furthermore, the translation-rotation interaction effect is not considered in the conventional constant-strength response spectra. Secondly, the influences of the three-degree-of-freedom (3DOF) modal parameters on the ductility demand were extensively studied. Thirdly, the normalized peak edge translation spectra were also investigated. It was found that the normalized peak edge translation resulting from a single vibration mode may be overestimated twofold by using the single-degree-of-freedom (SDOF) modal systems.

New foundations for Lewis modal systems

1957 ◽  
Vol 22 (2) ◽  
pp. 176-186 ◽  
Author(s):  
E. J. Lemmon
Keyword(s):  
Modal Logic ◽  
Propositional Calculus ◽  
Modal System ◽  
New Foundations ◽  
Image Position ◽  
Classical Propositional Calculus ◽  
Modal Systems

The main aims of this paper are firstly to present new and simpler postulate sets for certain well-known systems of modal logic, and secondly, in the light of these results, to suggest some new or newly formulated calculi, capable of interpretation as systems of epistemic or deontic modalities. The symbolism throughout is that of [9] (see especially Part III, Chapter I). In what follows, by a Lewis modal system is meant a system which (i) contains the full classical propositional calculus, (ii) is contained in the Lewis system S5, (iii) admits of the substitutability of tautologous equivalents, (iv) possesses as theses the four formulae:We shall also say that a system Σ1 is stricter than a system Σ2, if both are Lewis modal systems and Σ1 is contained in Σ2 but Σ2 is not contained in Σ1; and we shall call Σ1absolutely strict, if it possesses an infinity of irreducible modalities. Thus, the five systems of Lewis in [5], S1, S2, S3, S4, and S5, are all Lewis modal systems by this definition; they are in an order of decreasing strictness from S1 to S5; and S1 and S2 alone are absolutely strict.

scholarly journals Nonlinearity identification of Jesus Christ the King monument on the basis of modal parameters

2018 ◽  
Vol 196 ◽  
pp. 01054
Author(s):  
Jacek Grosel ◽  
Jakub Marcinowski ◽  
Wojciech Sawicki ◽  
Zbigniew Wójcicki
Keyword(s):  
Jesus Christ ◽  
Response Spectra ◽  
Modal Parameters ◽  
Interesting Alternative

The work presents an attempt to identify the nonlinearity of the structure using a simple autonomous vibration recorder. The vibrations were measured continuously for 4 days in three directions, which easily made it possible to record various load states of the structure. The analysis of the response spectra shows a change in the eigenfrequencies caused by the level of load, which is a measure of the non-linearity of the structure. The presented method is an interesting alternative to expensive multi-channel visit measurements, in which the equipment is compensated by the length of measurements

Statistical Analyses of Response Spectra on Medium-Stiff Soil Site

2011 ◽  
Vol 90-93 ◽  
pp. 1549-1554
Author(s):  
Wen Feng Liu ◽  
Xue Zhong Chen ◽  
Jie Ying Sui
Keyword(s):  
Goodness Of Fit ◽  
Probability Distributions ◽  
Response Spectra ◽  
Statistical Analyses ◽  
Statistical Average ◽  
Goodness Of Fit Test ◽  
Ductility Demand ◽  
Inelastic Responses ◽  
Soil Site ◽  
Stiff Soil

The analyses on the statistical response spectra have an important role in determining the earthquake demand. Elastic and inelastic spectra on acceleration of the 205 records on medium-stiff soil site for SDOF systems are presented in statistical analyses. The empirical probability distributions of the spectral values are derived according to the Kolmogorov-Smirnov (KS) goodness-of-fit test. The formula for statistical average spectra of the ground motion ensemble are recommended, which are valuable for current research and code revisal. The results show that the statistical averaged elastic α spectra fits well to the design spectra prescribed in Chinese code when the period is smaller than 2s. The inelastic responses decrease with the increase of ductility demand μ when μ<4. The coefficients of variance of the elastic and inelastic spectra are still large and the dispersion cannot be ignored. The probabilistic distribution of the spectra value on acceleration is validated as the lognormal distributions. The proposed formulas give a good fit to the statistical average values.

Damage Analysis of the Bridge Structure Based on the Modal Parameters

2011 ◽  
Vol 255-260 ◽  
pp. 1034-1038 ◽  
Author(s):  
Ke Ding
Keyword(s):  
Structural Damage ◽  
Vibration Mode ◽  
Modal Parameters ◽  
Damage Factor ◽  
Displacement Mode ◽  
Before And After ◽  
Bridge Structures ◽  
Modal Curvature ◽  
Bridge Damage

Reduction of intensity or rigidity and losses of quality of the bridge structures can induce the changes of modal parameters of the structure. It is possible to analyze and detect the damage of bridge based on comparing the changes of modal parameters of the structure before and after damaging. Natural frequency, displacement mode and modal curvature are the important parameters in dynamic Analysis. In this paper, their adaptive capacities to bridge damage assessment are discussed. And the damage factor is used to determine the damage location. Model experiments show that the damage factor not only reflects the position of bridge damage, and the damage factor of some vibration mode also indicates the length of damage element. At the equilibrium position of the vibration mode, it is difficult to determine structural damage using the damage factor.

Study on Structure Dynamic Characteristic of all Terrain Vehicle Frame

2013 ◽  
Vol 798-799 ◽  
pp. 255-258
Author(s):  
Jing Wang ◽  
Yong Wang
Keyword(s):  
Dynamic Characteristic ◽  
Vibration Frequency ◽  
Stress Condition ◽  
Vibration Mode ◽  
Modal Parameters ◽  
Dynamic Mode ◽  
Structure Dynamic ◽  
Vehicle Structure

Frame is one important part of all terrain vehicle, its dynamic Characteristic would influence the reliability and comfort of vehicle. All terrain vehicle frames Dynamic mode is analyzed and the modal parameters of the frame and mode of vibration was obtained and the inherent vibration mode and vibration frequency of the frame is ensured by Hypermesh-Ansys method to avoid the frame and engine resonance occurs and optimize stress condition while designing all terrain vehicle structure.

Mechanical Concepts for Simulation of Nonlinear Attachment of Engine on Aeroelastic Demonstrator

2016 ◽  
Vol 827 ◽  
pp. 201-204
Author(s):  
Jiří Čečrdle ◽  
Jaromír Maleček ◽  
Václav Hlavatý ◽  
Petr Malínek
Keyword(s):  
Research And Development ◽  
Vibration Mode ◽  
Modal Parameters ◽  
Design And Development ◽  
Modal Characteristics ◽  
Stiffness Characteristic

The article is focused on the design and development of the system simulating nonlinear attachment of the engine on the aeroelastic demonstrator. The aim is at obtaining the nonlinear (i.e., amplitude dependent) modal characteristics of the engine pitch vibration mode. Three mechanical concepts were tested to simulate the incremental stiffness characteristic of the engine pitch attachment. The nonlinear demonstrator is utilized for research and development of the advanced methods for the identification of nonlinear modal parameters.

Modal Analysis of the Gantry Crane Based on System

2012 ◽  
Vol 522 ◽  
pp. 524-528
Author(s):  
Yao Hua Si ◽  
Xue Li Cheng ◽  
Lin Chao An
Keyword(s):  
Stability Analysis ◽  
Simulation Model ◽  
Natural Frequency ◽  
Dynamic Characteristics ◽  
System Architecture ◽  
Vibration Mode ◽  
Point Of View ◽  
Modal Parameters ◽  
Gantry Crane ◽  
System Point

Modal of the gantry crane is developed by system point of view, Simulation model of the gantry crane system based on ANSYS is established, and each mode of the systems natural frequency and vibration mode were obtained. The dynamic characteristics of the system is evaluated, provide an important modal parameters for Gantry crane system architecture to optimize the design and stability analysis.

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