FOLKLORE CONCEPT: THE DEFINITION OF THE TERM, STRUCTURAL PARAMETERS AND TYPES

2018 ◽  
Vol 144 (6) ◽  
pp. 1439-1447
Author(s):  
Oksana Kuzmenko
Keyword(s):  
Structural Parameters ◽  
Definition Of

Topology Optimization of Dynamic Systems Under Uncertain Loads: An H∞-Norm-Based Approach

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Paolo Venini
Keyword(s):  
Topology Optimization ◽  
Structural Parameters ◽  
Goal Function ◽  
Dynamic Compliance ◽  
Case Scenario ◽  
Worst Case ◽  
Original Definition ◽  
Optimal Material ◽  
The One ◽  
Definition Of

An innovative approach to topology optimization of dynamic system is introduced that is based on the system transfer-function H∞-norm. As for the structure, the proposed strategy allows to determine the optimal material distribution that ensures the minimization of a suitable goal function, such as (an original definition of) the dynamic compliance. Load uncertainty is accounted for by means of a nonprobabilistic convex-set approach (Ben-Haim and Elishakoff, 1990, Convex Models of Uncertainty in Applied Mechanics, Elsevier Science, Amsterdam). At each iteration, the worst load is determined as the one that maximizes the current dynamic compliance so that the proposed strategy fits the so-called worst case scenario (WCS) approach. The overall approach consists of the repeated solution of the two steps (minimization of the dynamic compliance with respect to structural parameters and maximization of the dynamic compliance with respect to the acting load) until convergence is achieved. Results from representative numerical studies are eventually presented along with extensions to the proposed approach that are currently under development.

Neural Network-Based Identification of Structural Parameters in Multistory Buildings

2007 ◽  
pp. 342-361
Author(s):  
Snehashish Chakraverty
Keyword(s):  
Neural Network ◽  
Structural Parameters ◽  
Identification Algorithm ◽  
Initial Condition ◽  
Multistory Buildings ◽  
Soft Computing Techniques ◽  
Structural Responses ◽  
Real Earthquake ◽  
Definition Of ◽  
Efficiency And Reliability

A detailed study of the capabilities and powerfulness of soft computing techniques such as artificial neural network with respect to the identification of structural parameters and structural responses are presented. This chapter includes the definition of neural architectures and system identification of multistory structure. An efficient identification algorithm for the multistory structure subject to initial condition and ground displacement is presented. Response identification subject to real earthquake data has also been discussed. Several example problems are incorporated to show the efficiency and reliability of the proposed algorithm.

Modelling of high-symmetry nanoscale particles by small-angle scattering

2013 ◽  
Vol 47 (1) ◽  
pp. 84-94 ◽  
Author(s):  
Cassio Alves ◽  
Jan Skov Pedersen ◽  
Cristiano Luis Pinto Oliveira
Keyword(s):  
Small Angle ◽  
Structural Parameters ◽  
Small Angle Scattering ◽  
High Symmetry ◽  
Scattering Intensity ◽  
Angle Scattering ◽  
Small Set ◽  
Debye Formula ◽  
Definition Of ◽  
Theoretical Scattering

A versatile procedure to build high-symmetry objects and to calculate their corresponding small-angle scattering intensity is presented. Starting from a set of vertex positions, available from a large and extensible database, it is possible to build several types of bodies using spherical subunits. A fast implementation, based on the Debye formula using a histogram of distance, is then used to compute the theoretical scattering intensity. Since the model is built from the definition of a small set of parameters, it is possible to perform an optimization of structural parameters against experimental data. Finally, affine size polydispersities can be easily included by the rescaling of the histogram of the positions used in the calculations. Several examples of the calculations are presented, demonstrating the method and its applicability.

scholarly journals Numerical and Experimental Investigation on Parameter Identification of Time-Varying Dynamical System Using Hilbert Transform and Empirical Mode Decomposition

2014 ◽  
Vol 2014 ◽  
pp. 1-15
Author(s):  
Jun Chen ◽  
Guanyu Zhao
Keyword(s):  
Free Vibration ◽  
Empirical Mode Decomposition ◽  
Hilbert Transform ◽  
Instantaneous Frequency ◽  
Structural Parameters ◽  
Damping Ratio ◽  
Modal Parameters ◽  
Time Varying ◽  
Mode Decomposition ◽  
Definition Of

This paper proposes an approach to identifying time-varying structural modal parameters using the Hilbert transform and empirical mode decomposition. Definition of instantaneous frequency and instantaneous damping ratio based on Hilbert transform for single-degree-of-freedom (SDOF) system is first introduced. The following is the definition of Hilbert damping spectrum from which the time-varying damping ratio of multi-degree-of-freedom (MDOF) system can be calculated. Identification procedures for both instantaneous frequency and damping ratios based on their definition are then introduced. Applicability of the proposed identification algorithm has been validated through several numerical examples. The instantaneous frequency and damping ratios of SDOF system under free vibration and under sinusoidal and white noise excitation have been identified. The proposed method is also applied to MDOF system with slow and sudden changing structural parameters. The results demonstrate that when the system modal parameters are slowly changing, the instantaneous frequency could be easily and well identified with satisfied accuracy for all cases. However, the instantaneous damping ratio could be extracted only when the system is lightly damped. The damping results are better for free vibration situation than for the forced vibration cases. It is also shown that the suggested method can easily track the abrupt change of system modal parameter under free vibration. The proposed method is then applied to a 12-story short-lag shear wall structure model tested on a shaking table. The instantaneous dynamic properties of the structure were identified and were then introduced as known parameters into a finite element model. Comparisons with the numerical results using constant structural parameters demonstrate that the calculated structural responses using the identified time-varying parameters are much closer to the experimental results.

Study on Static Characteristics of an Integrated Six-Axis Accelerometer Based on Parallel Mechanism

2010 ◽  
Vol 129-131 ◽  
pp. 224-229
Author(s):  
Chun Zhan Yu ◽  
Xin Yi Zhang ◽  
Jin Hong Han ◽  
Li Chao Tian
Keyword(s):  
Parallel Mechanism ◽  
Structural Parameters ◽  
Fem Simulation ◽  
Angular Acceleration ◽  
Solution Space ◽  
Linear Acceleration ◽  
Static Characteristic ◽  
Sensing Element ◽  
Definition Of ◽  
The Relationship

It is difficult to fabricate one sensing element to simultaneously sense three linear acceleration components and three angular acceleration components, so as to find rare reports on six-axis accelerometer. The aim of this on-going project was to research an integrated six-axis accelerometer using parallel mechanism as the structure for sensing element. In order to optimize so many parameters, the paper defined the important static characteristic indices, analyzed the relationship between indices and structural parameters of sensing element. Based on the definition of the indices, the structural parameters were designed by the physical model of solution space. Finally, FEM simulation experiment is carried out to verify effectiveness of the method.

scholarly journals WinPSSP: a revamp of the computer program PSSP and its performance solving the crystal structures of small organic compounds and solids of biological and pharmaceutical interest

2017 ◽  
Vol 50 (1) ◽  
pp. 293-303 ◽  
Author(s):  
Silvina Pagola ◽  
Alekos Polymeros ◽  
Nikolaos Kourkoumelis
Keyword(s):  
Crystal Structure ◽  
Degrees Of Freedom ◽  
Structural Parameters ◽  
Rietveld Analysis ◽  
Molecular Solids ◽  
Structure Information ◽  
Individual Solution ◽  
Structure Determinations ◽  
Definition Of ◽  
Integrated Intensities

The direct-space methods software Powder Structure Solution Program (PSSP) [Pagola & Stephens (2010). J. Appl. Cryst. 43, 370–376] has been migrated to the Windows OS and the code has been optimized for fast runs. WinPSSP is a user-friendly graphical user interface that allows the input of preliminary crystal structure information, integrated intensities of the reflections and FWHM, the definition of structural parameters and a simulated annealing schedule, and the visualization of the calculated and experimental diffraction data overlaid for each individual solution. The solutions are reported as filename.cif files, which can be used to analyze packing motifs and chemical bonding, and to input the atomic coordinates into the Rietveld analysis software GSAS. WinPSSP performance in straightforward crystal structure determinations has been evaluated using 18 molecular solids with 6–20 degrees of freedom. The free-distribution program as well as multimedia tutorials can be accessed at http://users.uoi.gr/nkourkou/winpssp/.

scholarly journals Regulatory and documentary standards of the sustainable development of urban agglomerations in the Russian Federation

2021 ◽  
Vol 27 (1) ◽  
pp. 17-28
Author(s):  
Vitaly Belozerov ◽  
Natalia Shchitova ◽  
Nikolai Sopnev
Keyword(s):  
Sustainable Development ◽  
Russian Federation ◽  
Structural Parameters ◽  
The Sustainable Development ◽  
Urban Agglomerations ◽  
The Past ◽  
Territorial Planning ◽  
Innovative Management ◽  
The Russian Federation ◽  
Definition Of

The article considers the experience of classification documents of the territorial planning and management of urban agglomerations in the Russian Federation. We have analyzed the documents of the federal level the main aim of which is regulating the processes of formation and development of agglomerations in the country. The documents developed in the regions over the past ten years, which regulate the functioning of all Russian urban agglomerations including laws, concepts, strategies, territorial planning schemes, inter-municipal agreements, and regulations on the activities of coordination councils are considered in detail. A comparative analysis of the documents allowed us to group agglomerations according to the degree of representation of the regulatory and documentary basis. There are five groups of agglomerations that differ in the number of documents and the degree of elaboration of agglomeration issues. The results revealed a significant gap between the selected groups. For agglomerations of the first and second groups we have prepared the complete sets of documentation, which reflect sufficiently the main parameters of agglomerations as integral system formations. For agglomerations included in the fourth group, there are no special documents, there are also some relevant materials in the regional documents of strategic and territorial planning which are characterized by poor elaboration. Agglomerations of the fifth group are not provided with regulatory documents at all, they are not considered as special formations. The analysis can contribute to improving the methodology of agglomeration development, understanding the need to expand and improve approaches to the management of urban agglomerations as integral objects. It is obvious that the urgent problem of sustainable development and functioning of urban agglomerations is the need to develop an innovative management model, its coordination with the regulatory framework of regional management structures, and a clear definition of conceptual and terminological and spatial-structural parameters.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

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