Natural Vibration Frequency Definition Of Turbine Blades

A turbine compressor package is used for pipeline gas transmission. When operating, compressor turbine blades develop vibration, which increases the number of dynamic stress cycles and results in the blade failure. The present study aims to determine the frequency of natural blade vibration and to consider it in the context of the blade repair process. In the first stage of the study, an oscillating contour is developed to generate standing oscillation wave which characteristics are used as experimental data. To process those data, a mathematical model is developed to calculate the blade resonant frequency. Finally, the boundaries of the assured quality area are determined. Blade operation capacity analysis method will allow us to reduce the number of environmentally dangerous experiments.

PROBABILITY, RARITY, INTEREST, AND SURPRISE

THE unusual is often interesting. Moreover, the frequency definition of probability, which is the one consciously or tacitly used in all applications to experience, makes it clear that an improbable event means precisely a rare event. Hence, an improbable event is often interesting. But is an improbable event always interesting? We shall see that is is not. If an event actually occurs, and if its probability, as reckoned before its occurrence, is very small, is the fact of its occurrence surprising? The answer is that it may be, or it may not be. Suppose one shuffles a pack of cards and deals off a single bridge hand of thirteen cards. The probability, as reckoned before the event, that this hand contain any thirteen specified cards is 1 divided by 635,013,559,600. Thus the probability of any one specified set of thirteen cards is, anyone would agree, very small. When one hand of thirteen cards is dealt in this way there are, of course, precisely 635,013,559,600 different hands that can appear. All these billions of hands are, furthermore, equally likely to occur; and one of them is absolutely certain to occur every time a hand is so dealt. Thus, although any one particular hand is an improbable event, and so a rare event, no one particular hand has any right to be called a surprising event. Any hand that occurs is simply one out of a number of exactly equally likely events, some one of which was bound to happen. There is no basis for being surprised at the one that did happen, for it was precisely as likely (or as unlikely, if you will) to have happened as any other particular one.