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1

Hybrid reliability modelling under general uncertainty

Guo R., Cui Y., Thiart C., Guo D.

Journal of Polish Safety and Reliability Association

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2010

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Vol. 1, No. 1

115--122

EN

The real world phenomena are often facing the co-existence reality of different formality of uncertainty and thus the probabilistic reliability modeling practices are very doubtful. Under complicated uncertainty environments, hybrid variable modeling is important in reliability and risk analysis, which includes Bayesian distributional theory, random fuzzy distributional theory, as well as fuzzy random distributional theory as special distribution families. In this paper, we define a new hybrid lifetime which is specified by a random lifetime distribution with an uncertain distributed parameter, which is called as random uncertain hybrid lifetime. We furthermore define the average chance distribution as a quality index for quantifying the hybrid lifetime and accordingly the average chance reliability is derived.

2

Dyskretny system paraboliczny o niepewnych parametrach

Oprzędkiewicz K.

Przegląd Elektrotechniczny

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2008

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R. 84, nr 9

179-187

PL

W pracy omówiono zagadnienia dyskretyzacji równania stanu opisującego system paraboliczny o niepewnych parametrach. Rozważono system z dwuwymiarową przestrzenią niepewnych parametrów opisany abstrakcyjnym równaniem stanu w przestrzeni Hiilberta. Dla rozważanego systemu podano warunki dekompozycji widma bazujące na geometrycznej interpretacji widma systemu. Wykazano, że dyskretyzacja nie zmienia warunków dekompozycji widma dla dowolnej wartości okresu próbkowania.

EN

In the paper the discretisation problem for an uncertain - parameter parabolic system was discussed. The system under consideration is described by an abstract state – space equation in the Hilbert space. For the discussed system spectrum decomposition conditions were proposed. To the formulate these conditions the geometric interpretation of the system’s spectrum was applied. The main conclusion from the paper is, that the discretisation does not change the spectrum decomposition conditions for each value of the sample time.

3

Stochastic finite element method for sensitivity analysis of structures

Bhattacharyya B., Chakraborty S.

Applied Mechanics and Engineering

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2000

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Vol. 5, no 4

867-882

EN

The conventional sensitivity analysis of structures is based on the assumption of complete certainty of design parameters. However, occurrence of uncertainty is unavoidable in structures. In the present work, an attempt has been made to study the response sensitivity, considering the effect of uncertainty in structural design parameters. The random parameters are modeled as Gaussian stochastic process and simulated through covariance matrix decomposition. The advantages of Neumann expansion technique has been utilized in deriving the finite element solution of the response sensitivity within the framework of Monte Carlo simulation. Numerical examples are presented to explain the accuracy and efficacy of Neumann expansion method over direct simulation the process.