“Exact” Three-Dimensional Linear and Nonlinear Seismic Analysis of Structures with Two-Dimensional Models

2003 ◽  
Vol 19 (4) ◽  
pp. 897-912 ◽  
Author(s):  
Michael Mehrain ◽  
Farzad Naeim
Keyword(s):  
Structural Analysis ◽  
Nonlinear Analysis ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Modeling Technique ◽  
Two Dimensional ◽  
Single Model ◽  
Relative Ease ◽  
Conventional Analysis ◽  
Linear And Nonlinear

This paper presents a modeling technique by which a complete three-dimensional (3-D) structural analysis of a structure can be performed using two-dimensional (2-D) models, and hence 2-D software. The approach includes the effect of torsion, walls perpendicular and inclined to the direction of motion as well as walls with L, T, and H shapes in plan. Diaphragm displacements are easily modeled. The method can be used with linear and nonlinear analysis. Nonlinearity in the diaphragms can also be modeled with relative ease. Furthermore, unlike the conventional analysis that requires two 2-D models, one in each direction of motion, to model the 3-D structure, this approach requires only a single model.

scholarly journals Application of Linear and Nonlinear Graphs in Structural Synthesis of Kinematic Chains

1973 ◽  
Vol 95 (2) ◽  
pp. 525-532 ◽  
Author(s):  
M. Huang ◽  
A. H. Soni
Keyword(s):  
Mathematical Model ◽  
Graph Theory ◽  
Structural Analysis ◽  
Three Dimensional ◽  
Structural Synthesis ◽  
Kinematic Chains ◽  
Piston Cylinder ◽  
General Constraints ◽  
Analysis And Synthesis ◽  
Linear And Nonlinear

Using graph theory and Polya’s theory of counting, the present paper performs structural synthesis and analysis of planar and three-dimensional kinematic chains. The Section 2 of the paper develops a mathematical model that permits one to perform structural analysis and synthesis of planar kinematic chains with kinematic elements such as revolute pairs, cam pairs, springs, belt-pulley, piston-cylinder, and gears. The theory developed is applied to enumerate eight-link kinematic chains with these kinematic elements. The Section 3 of the paper develops a mathematical model that permits one to perform structural analysis and synthesis of multi-loop spatial kinematic chains with higher and lower kinematic pairs. The theory developed is applied to enumerate all possible two-loop kinematic chains with or without general constraints.

scholarly journals Using Demonstrations during Lectures

2001 ◽  
Vol 18 (1) ◽  
pp. 114-119
Author(s):  
Julieta Fierro
Keyword(s):  
Elementary Education ◽  
Three Dimensional ◽  
Teaching Science ◽  
Two Dimensional ◽  
Physics Teachers ◽  
Relative Ease ◽  
Teacher Workshops ◽  
The Universe

AbstractI shall present a series of easy demonstrations that can be carried out during formal astronomy lectures. Since astronomy is physics we have developed on Earth applied to celestial objects, there are many useful experiments that can be carried out with relative ease by physics teachers in order to help pupils grasp the workings of the universe and to relate them with every day experiences. One of the difficulties in teaching science is that we use two-dimensional pictures to explain a three-dimensional reality. Using models helps students understand some of the properties of celestial objects. Although it is important to have pupils experiment on their own, some demonstrations are so simple that it is enough to have the teacher carry them out during the lecture to have pupils grasp their importance or at least keep their attention focused on the topic at hand. The demonstrations can be used in elementary education as well as in introductory astronomy courses and teacher workshops.

scholarly journals Linear and Nonlinear Convection with an Aligned Magnetic Field

1990 ◽  
Vol 142 ◽  
pp. 135-136
Author(s):  
N. Rudraiah ◽  
I S Shivakumara ◽  
P Geetavani
Keyword(s):  
Magnetic Field ◽  
Fluid Layer ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Horizontal Magnetic Field ◽  
Nonlinear Convection ◽  
Linear And Nonlinear ◽  
Horizontal Fluid Layer ◽  
Aligned Magnetic Field

The effect of horizontal magnetic field on the onset of three-dimensional convection in a horizontal fluid layer is studied. It is found that the two-dimensional solutions are unstable to three-dimensional disturbances. A detailed bifurcation study is reported.

Linear and nonlinear statistics of extreme waves

2017 ◽  
Vol 32 (2) ◽  
Author(s):  
Dmitry V. Chalikov
Keyword(s):  
Nonlinear Model ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Extreme Waves ◽  
Linear Waves ◽  
Wave Heights ◽  
Linear And Nonlinear ◽  
Nonlinear Statistics ◽  
Integral Probability

AbstractThe probability of extremely high waves is calculated by two methods. The first method is based on the direct numerical simulation of two-dimensional wave field using a three-dimensional nonlinear model. The second method consists in calculation of the probability of wave heights over ensemble of fields representing a superposition of linear waves with random phases and a spectrum similar to that obtained in the nonlinear model. It is shown that the integral probability of extreme waves are very close to each other in both cases. This implies that the role of nonlinearity in the generation of extreme waves is probably not so important as it was assumed in most papers considering this phenomenon.

A method for the derivation of load effect envelopes based on statistical considerations

1993 ◽  
Vol 20 (2) ◽  
pp. 201-209
Author(s):  
Eugene J. O'Brien ◽  
Robert E. Loov
Keyword(s):  
Structural Analysis ◽  
Three Dimensional ◽  
Elastic Analysis ◽  
Two Dimensional ◽  
Statistical Parameters ◽  
Simple Method ◽  
Load Effect ◽  
Linear Elastic ◽  
Derived Design ◽  
Usual Process

A simple method is proposed as a substitute for the usual process of factoring loads, performing a linear elastic analysis, and determining an envelope of the results. The method is based on statistical principles, but only a minimum knowledge of statistics is required for its use. It involves conventional structural analysis followed by some processing of the results which could readily be incorporated into existing computer programs.The practice of performing two-dimensional analyses on parts of three-dimensional structures is possible with the proposed approach. The implications are clarified and the necessary statistical parameters are derived.Deterministically derived design envelopes represent all the extremes of loading that can reasonably be considered. The envelopes found by the new method not only reflect loading variations but also consider their relative probabilities of occurrence so that excursions beyond the envelope are expected to be equally infrequent along the entire length of the structure. Inconsistencies inherent in the conventional approach are highlighted by comparison with the proposed method for a number of examples. Key words: probabilistic, safety, load, imposed load, load effect envelope, building.

Modified Wavelet-Based Multilevel Discrete-Continual Finite Element Method for Local Structural Analysis - Part 1: Continual and Discrete-Continual Formulations of the Problems

2014 ◽  
Vol 670-671 ◽  
pp. 720-723 ◽  
Author(s):  
Pavel A. Akimov ◽  
Marina L. Mozgaleva ◽  
Mojtaba Aslami ◽  
Oleg A. Negrozov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Three Dimensional ◽  
Accurate Solution ◽  
Geometrical Parameters ◽  
Two Dimensional ◽  
Boundary Problems ◽  
Piecewise Constant ◽  
Element Method

The distinctive paper is devoted to wavelet-based discrete-continual finite element method (WDCFEM) of structural analysis. Two-dimensional and three-dimensional problems of analysis of structures with piecewise constant physical and geometrical parameters along so-called “basic” direction are under consideration. High-accuracy solution of the corresponding problems at all points of the model is not required normally, it is necessary to find only the most accurate solution in some pre-known local domains. Wavelet analysis is a powerful and effective tool for corresponding researches. Initial continual and discrete-continual formulations of multipoint boundary problems of two-dimensional and three-dimensional structural analysis are presented.

Modified Wavelet-Based Multilevel Discrete-Continual Finite Element Method for Local Structural Analysis - Part 2: Reduced Formulations of the Problems in Haar Basis

2014 ◽  
Vol 670-671 ◽  
pp. 724-727 ◽  
Author(s):  
Pavel A. Akimov ◽  
Marina L. Mozgaleva ◽  
Mojtaba Aslami ◽  
Oleg A. Negrozov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Three Dimensional ◽  
Haar Wavelet ◽  
Wavelet Basis ◽  
Two Dimensional ◽  
Governing Equations ◽  
Boundary Problems ◽  
Element Method

The distinctive paper is devoted to wavelet-based discrete-continual finite element method (WDCFEM) of structural analysis. Discrete-continual formulations of multipoint boundary problems of two-dimensional and three-dimensional structural analysis are transformed to corresponding localized formulations by using the discrete Haar wavelet basis and finally, with the use of averaging and reduction algorithms, the localized and reduced governing equations are obtained. Special algorithms of localization with respect to each degree of freedom are presented.

scholarly journals A consideration of the torsional response of building frames

1979 ◽  
Vol 12 (1) ◽  
pp. 11-21
Author(s):  
A. Rutenberg
Keyword(s):  
Degrees Of Freedom ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Building Structures ◽  
Two Dimensional ◽  
Building Frames ◽  
Torsional Response ◽  
Modal Coupling ◽  
Structural Engineer ◽  
History Of

History of elastic static procedures for the seismic analysis of torsionally unbalanced building structures is briefly reviewed. It is suggested that the provisions of NZS 4203:1976, accounting for modal coupling, are based on inconsistent interpretation of results from well known two-degrees-of-freedom models. An alternative dynamic procedure
is described which, while retaining the basic two-dimensional features
of NZS 4203:1976 torsional provisions, is equivalent to three-dimensional modal spectral analysis. The procedure also results in a substantial simplification of the analysis compared with standard dynamic computer techniques now available to the structural engineer.

Two-dimensional nuclear magnetic resonance at 500 MHz: the structural elucidation of a Salmonella serogroup N polysaccharide antigen

1986 ◽  
Vol 64 (2) ◽  
pp. 255-264 ◽  
Author(s):  
David R. Bundle ◽  
Manfred Gerken ◽  
Malcolm B. Perry
Keyword(s):  
Structural Analysis ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Three Dimensional Model ◽  
One Dimensional ◽  
Whole Cells ◽  
O Antigen ◽  
Acetyl Group ◽  
Semi Empirical ◽  
C Nmr

High resolution 1H and 13C nmr spectroscopy at 500 MHz and 125 MHz was used for the structural analysis of the O-antigen of Salmonellalandau, which belongs to the Kauffmann–White serogroup N. This bacterial lipopolysaccharide was extracted from whole cells and hydrolyzed by mild acid to give lipid-free O-polysaccharide. Conventional one-dimensional 1H and 13C nmr data showed the polysaccharide to contain four monosaccharides in each repeating unit and, in addition, to carry an average of one O-acetyl group for every two repeating units. Two-dimensional nmr experiments aided the unambiguous assignment of the 1H and 13C resonances and thereby permitted the structural analysis of this polysaccharide by nmr techniques alone. The structure of the de-O-acetylated repeating unit was established as [Formula: see text][Formula: see text] through the use of methods which included homonuclear shift correlated (COSY and NOESY) experiments. The interpretation of this data was supported and simplified by consideration of firmly established 13C chemical shift assignments obtained from a heteronuclear 1H/13C shift correlated experiment. A three-dimensional model of the O-antigen obtained by semi-empirical calculations is shown to be consistent with interatomic distance constraints imposed by data from 2-D NOESY and one-dimensional nOe difference spectroscopy.

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