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Article
Publication date: 15 July 2019

R.R. Kumar, P.K. Karsh, Vaishali , K.M. Pandey and S. Dey

The purpose of this paper is to investigate the first three stochastic natural frequencies of skewed sandwich plates, considering uncertain system parameters. To conduct…

Abstract

Purpose

The purpose of this paper is to investigate the first three stochastic natural frequencies of skewed sandwich plates, considering uncertain system parameters. To conduct the sensitivity analysis for checking the criticality of input parameters.

Design/methodology/approach

The theoretical formulation is developed based on higher-order-zigzag theory in accordance with the radial basis function (RBF) and stochastic finite element (FE) model. A cubic function is considered for in-plane displacement over thickness while a quadratic function is considered for transverse displacement within the core and remains constant in the facesheet. RBF is used as a surrogate model to achieve computational efficiency and accuracy. In the present study, the individual and combined effect of ply-orientation angle, skew angle, number of lamina, core thickness and material properties are considered for natural frequency analysis of sandwich plates.

Findings

Results presented in this paper illustrates that the skewness in the sandwich plate significantly affects the global dynamic behaviour of the structure. RBF surrogate model coupled with stochastic FE approach significantly reduced the computational time (more than 1/18 times) compared to direct Monte Carlo simulation approach.

Originality/value

The stochastic results for dynamic stability of sandwich plates show that the inevitable source uncertainties present in the input parameters result in significant variation from the deterministic value demonstrates the need for inclusive design paradigm considering stochastic effects. The present paper comprehensively establishes a generalized new RBF-based FE approach for efficient stochastic analysis, which can be applicable to other complex structures too.

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Article
Publication date: 1 July 2003

M. Patel and H. Sabelli

Mathematical bios and heartbeat series show an inverse relation between frequency and power; the time series of differences between successive terms of cardiac and…

Abstract

Mathematical bios and heartbeat series show an inverse relation between frequency and power; the time series of differences between successive terms of cardiac and mathematical chaos shows a direct relation between frequency and power. Other statistical analyses differentiate these biotic series from stochastically generated 1/f noise. The time series of complex biological and economic processes as well as mathematical bios show asymmetry, positive autocorrelation, and extended partial autocorrelation. Random, chaotic and stochastic models show symmetric statistical distributions, and no partial autocorrelation. The percentage of continuous proportions is high in cardiac, economic, and mathematical biotic series, and scarce in pink noise and chaos. These findings differentiate creative biotic processes from chaotic and stochastic series. We propose that the widespread 1/f power spectrum found in natural processes represents the integration of the fundamental relation between frequency and energy stated in Planck's law. Natural creativity emerges from determined interactions rather than from the accumulation of accidental random changes.

Details

Kybernetes, vol. 32 no. 5/6
Type: Research Article
ISSN: 0368-492X

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Article
Publication date: 16 June 2010

Jhojan Enrique Rojas, Othmane Bendaou, Abdelkhalak El Hami and Domingos Rade

The purpose of this paper is to present a deterministic, stochastic and reliability analysis through numerical simulations in 2D and 3D dynamic fluid‐structure interaction…

Abstract

Purpose

The purpose of this paper is to present a deterministic, stochastic and reliability analysis through numerical simulations in 2D and 3D dynamic fluid‐structure interaction problems.

Design/methodology/approach

The perturbation methods allied to reliability analysis are applied to fluid‐structure finite element models. Reliability analysis couples finite element analysis with first and second order reliability methods and ant colony optimization in a modified first order reliability method.

Findings

Results obtained show the potentialities of the proposed methodology and encourage improvement of this procedure for use in complex coupled fluid‐structure systems.

Originality/value

The understanding of the mechanical interaction between a fluid and an elastic solid has a capital importance in several industrial applications. In order to couple the behaviour of two different media, deterministic models have been proposed. However, stochastic analysis has been developed to deal with the statistical nature of fluid‐structure interaction parameters. Moreover, probabilistic‐based reliability analysis intends to find safe and cost‐effective projects.

Details

Multidiscipline Modeling in Materials and Structures, vol. 6 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 1 June 1994

P.R. Masani

Presents the scientific methodology from the enlarged cybernetical perspective that recognizes the anisotropy of time, the probabilistic character of natural laws, and the…

Abstract

Presents the scientific methodology from the enlarged cybernetical perspective that recognizes the anisotropy of time, the probabilistic character of natural laws, and the entry that the incomplete determinism in Nature opens to the occurrence of innovation, growth, organization, teleology communication, control, contest and freedom. The new tier to the methodological edifice that cybernetics provides stands on the earlier tiers, which go back to the Ionians (c. 500 BC). However, the new insights reveal flaws in the earlier tiers, and their removal strengthens the entire edifice. The new concepts of teleological activity and contest allow the clear demarcation of the military sciences as those whose subject matter is teleological activity involving contest. The paramount question “what ought to be done”, outside the empirical realm, is embraced by the scientific methodology. It also embraces the cognitive sciences that ask how the human mind is able to discover, and how the sequence of discoveries might converge to a true description of reality.

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Kybernetes, vol. 23 no. 4
Type: Research Article
ISSN: 0368-492X

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Article
Publication date: 1 June 1997

Jaroslav Mackerle

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…

Abstract

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.

Details

Engineering Computations, vol. 14 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 4 September 2020

Veli Yilanci and Muhammed Sehid Gorus

In this study, we aim to test the stochastic convergence of per capita clean energy use in 30 OECD (Organization for Economic Co-operation and Development) countries for…

Abstract

Purpose

In this study, we aim to test the stochastic convergence of per capita clean energy use in 30 OECD (Organization for Economic Co-operation and Development) countries for the period of 1965–2017.

Design/methodology/approach

This study employed both linear and nonlinear panel unit root tests, and unlike other studies, this study allowed fractional values in addition to integer values for frequencies in the Fourier functions. Integer values of frequency indicate temporary breaks, while fractional values show permanent breaks.

Findings

The results of the linear panel unit root test indicate that clean energy use does not converge to group average for almost all OECD countries. However, the results of nonlinear panel unit root tests provide evidence that the stochastic convergence hypothesis of clean energy consumption cannot be rejected for most countries. This study does not find any evidence for stochastic convergence of clean energy use in Australia, Canada, Denmark, Ireland, Norway or Sweden. Therefore, the policies regarding clean energy are mandatory in these countries due to their effectiveness. This study also reveals that there are permanent structural breaks in the convergence process of clean energy consumption in approximately half of OECD countries.

Originality/value

This study considers temporary and permanent smooth structural shifts in addition to nonlinearity when testing the stationarity of clean energy consumption in a country i relative to the group average. This new method eliminates deficiencies of the previous panel data techniques. Thus, it provides more reliable results compared to existing literature.

Details

Management of Environmental Quality: An International Journal, vol. 32 no. 2
Type: Research Article
ISSN: 1477-7835

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Book part
Publication date: 20 January 2005

Leo Egghe

Abstract

Details

Power Laws in the Information Production Process: Lotkaian Informetrics
Type: Book
ISBN: 978-0-12088-753-8

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Article
Publication date: 12 November 2019

Zhen Li, Dejian Li, Yao Lu, Kepei Cheng and Qianqiu Wu

The purpose of this paper is to obtain the response time history curves of vertical and lateral acceleration in the span of the main beam under different loads through the…

Abstract

Purpose

The purpose of this paper is to obtain the response time history curves of vertical and lateral acceleration in the span of the main beam under different loads through the finite element time-history analysis method, so as to realize the Serviceability Analysis of a Cable-Supported Footbridge Subjected to Human-Induced Loads, taking the long-span cable-supported footbridge over Dongtan River as an example.

Design/methodology/approach

The finite element method is used for analysis of the footbridge.

Findings

It is found that under the condition of low-density pedestrians walking freely, the response of human vertical vibration acceleration and the load conditions of pedestrian overpasses cannot meet the requirements of normal use. Therefore, the vertical acceleration of the footbridge should be designed to reduce vibration. Under these two loading conditions, the lateral acceleration response meets the requirements of normal use.

Originality/value

On the basis of summarizing the research at home and abroad, the analysis of human-induced vibration is mainly considered from two aspects: frequency regulation and dynamic response control. The walking load models mainly include Fourier series model, self-excitation model, impulse model, stochastic model and more; the crowd load models are divided into groups: low-density crowd walking freely, high-density crowd flowing and more. Therefore, it is very important to calculate the structural vibration response in the design of long-span cable-supported footbridges under pedestrian excitation to meet comfort requirements.

Details

International Journal of Structural Integrity, vol. 11 no. 3
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 1 May 2006

Sung Yi, Sang Kyoo Park and Kiat Choon Teo

To provide a design guideline for an automotive electronic module in order to improve its reliability in elevated environmental environments as well as in vibration environments.

Abstract

Purpose

To provide a design guideline for an automotive electronic module in order to improve its reliability in elevated environmental environments as well as in vibration environments.

Design/methodology/approach

Wire looping profiles, gel heights, and effects of mechanical vibration on aluminium wire bond failures are studied. Natural frequencies of various wire profiles are evaluated and effects of gel heights on reliability of products are studied using stochastic finite element analyses. The frequency dependent properties of silicone gels used in electronic modules are characterized by the corn and plate test. An experiment was also conducted in order to confirm numerical results.

Findings

The present study shows that the gel plays an important role in wire bond failures and reliability of the product. The gel reduces the amplitude of vibration of electronic modules due to its damping characteristics. However, both analytic and experimental results indicate that the gel imposes extra weight on the wires and may induce stresses on heels.

Research limitations/implications

In the future study, it is suggested that other gel materials should be studied since the properties of gel strongly depend on the frequency which will affect the fatigue behavior of bonding wires.

Practical implications

The findings can be used as general design guidelines for wire bonding for automotive electronic modules.

Originality/value

The results will be very useful to design bonding wires for automotive electronic modules.

Details

Microelectronics International, vol. 23 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 20 February 2007

Vladimir S. Lerner

Science of systems requires a specific and constructive mathematical model and language, which describe jointly such systemic categories as adaptation, self‐organization…

Abstract

Purpose

Science of systems requires a specific and constructive mathematical model and language, which describe jointly such systemic categories as adaptation, self‐organization, complexity, evolution, and bring the applied tools for building a system model for each specific object of a diverse nature. This formalism should be connected directly with a world of information and computer applications of systemic model, developed for a particular object. The considered information systems theory (IST) is aimed at building a bridge between the mathematical systemic formalism and information technologies to develop a constructive systemic model of revealing information regularities and specific information code for each object.

Design/methodology/approach

To fulfill this goal and the considered systems' definition, the IST joins two main concepts: unified information description of interacted flows, initiated by the sources of different nature, with common information language and systems modeling methodology, applied to distinct interdisciplinary objects; general system's information formalism for building the model, which allows expressing mathematically the system's regularities and main systemic mechanisms.

Findings

The formalism of informational macrodynamics (IMD), based of the minimax variational principle, reveals the system model's main layers: microlevel stochastics, macrolevel dynamics, hierarchical dynamic network (IN) of information structures, its minimal logic, and optimal code of communication language, generated by the IN hierarchy, dynamics, and geometry. The system's complex dynamics originate information geometry and evolution with the functional information mechanisms of ordering, cooperation, mutation, stability, diversity, adaptation, self‐organization, and the double helix's genetic code.

Practical implications

The developed IMD's theoretical computer‐based methodology and the software has been applied to such areas as technology, communications, computer science, intelligent processes, biology, economy, management, and other nonphysical and physical subjects.

Originality/value

The IMD's macrodynamics of uncertainties connect randomness and regularities, stochastic and determinism, reversibility and irreversibility, symmetry and asymmetry, stability and instability, structurization and stochastization, order and disorder, as a result of micro‐macrolevel's interactions for an open system, when the external environment can change the model's structure.

Details

Kybernetes, vol. 36 no. 2
Type: Research Article
ISSN: 0368-492X

Keywords

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