Fuzzy reliability analysis of structures by using the method of fuzzy optimization
- Shanghai Jiao Tong Univ. (China). Dept. of Naval Architecture and Ocean Engineering
There are two kinds of uncertainties in safety assessment of engineering structures. One is of the nature of randomness, and the other fuzziness. Fuzzy uncertainties exist in defining certain structural performances, conditions, parameters, and their interrelationships. The theory of fuzzy sets should be employed to cope with the fuzzy uncertainties. In this paper, a general definition for structural failure considering the fuzzy uncertainties is introduced firstly. Failure of the structure is modelled by a fuzzy event, and described by the membership function. The limit state surface is then replaced by a fuzzy limit state zone, in which every point represents a state belonging to the failure with a certain degree of membership. Then a fuzzy optimization problem for solving the reliability index is formulated. In classical structural reliability theory, the reliability index is defined by the minimum distance from the limit state surface to the origin of the standard normal variable space. It can be evaluated by solving an optimization problem. When the fuzzy uncertainties are taken into consideration, the crisp limit state surface becomes a fuzzy limit state zone. In this case, a corresponding fuzzy optimization problem can be formulated. Fuzzy reliability index can be obtained by solving the fuzzy optimization problem by an iterative procedure with some criteria base on the fuzzy decision-making. Numerical examples are given in the paper.
- OSTI ID:
- 455470
- Report Number(s):
- CONF-9606279--; ISBN 0-7918-1491-2
- Country of Publication:
- United States
- Language:
- English
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