The Research Of Non-probability Reliability

The analysis of the structural system reliability is the hot issues in the research of structural reliability theory, reliability analysis of structural elements has matured after several decades of development. However, structure system reliability problems have not reached practical level due to the complexity of the structure system and the uncertainty of structural problems such as load and failure mode correlation. The emergence of the nonprobabilistic reliability concept brought new method for structural system reliability analysis. In order to evaluate the structure of the safety and reliability effectively, we should take reasonable solution according to the different engineering problems. The mature of non-probability reliability theory will promote the reliability analysis of structural system in practical process. With the research in-depth, people realized the fuzziness and randomness,as uncertain factors affecting the safety of structure system,considering the influence of fuzziness, Using the fuzzy mathematics to have comprehensive evaluation on structural reliability,fuzzy reliability arises at the historic moment. Practice has proved that when calculating the structural reliability, fuzzy reliability is more accord with the engineering practice than traditional reliability. The main work of this paper are as follows:First, discusses the advantages and disadvantages of probability reliability and non-probability reliability respectively. Through the example of structural system reliability probability and non-probability reliability analysis to summarizes the advantages and limitations of non-probability reliability in the process of applying.Second, in accordance with the 3? law, it transforms theory probability reliability and non-probability reliability to each other. Under the normal distribution random, builds the relationship between the probability reliability and non-probability reliability, finds that: when the probability reliability index is constant, with the increase of n(range increasing), degree of discrete uncertain parameters are bigger, the greater the probability and reliability index and the ratio of the probability and reliability index also increases, the non-probability reliability index decreased; the narrower the variable interval, the higher the non probabilistic reliability to describe the safer(and describe the closer the probabilistic reliability);variable range is wider, and the smaller, the less the probability reliability to describe security(and describe the big deviation probability reliability).Based on the relationship of the probability index between the non-probability reliability indexes, concluded that it is safety and applicability to descript the probability of reliability and the non-probability reliability. The more narrow interval, the appropriate description of the structure reliability in the practical engineering, the big range description is often deviation from probability reliability. At this time with the non-probability reliability index to describe the structure reliability is unrealistic.Third, From the change of the ratio of the variance of resistance and load effect the variance to discuss with the link between reliability of probability theory and probability theory. 1:3 is the special circumstances among 1: n.Fourth, when ?1?? ?1, we can't judge that the structure is reliable or failure. Under the 3? law, transforming the interval variables into normal random variables or from the resistance and load effect of discrete degree or under the ratio of the relationship between probability and reliability index into probability and reliability index, then using the theory of probability and reliability to illustrate the safety degree of the structure or the failure degree. It tries to determine the structural reliability by looking for non-probabilistic reliability indicators point.Fifth, studying the relationship between the probability reliability index and non-probability reliability index under the multi-dimensional variables, find that it is different from the discovery in the case of double variable, have already couldn't from the resistance of the variance and the ratio of the variance of load effect to discuss the connection between them. It is not only the coefficient of linear equation, but also the increase of the random variable can influence them.Sixth, considering the fuzziness, comparing the traditional reliability theory and fuzzy reliability theory, found that the result of conventional reliability method to calculate the reliability is bigger than the fuzzy reliability, which would be dangerous,fuzzy reliability method is relatively conservative. What's more, it found out that the non-probability of fuzzy reliability can not only handle with the mixture uncertainty model, containing interval variable and random variable, reducing the difference with the actual structure, more species in structure analysis; but also inherited the advantage of the non-probabilistic reliability method in calculating.