lompiacv
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ugg milano Statistical processing of test data and |
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Statistical processing of test data and error analysis of the first basic concepts of probability theory stresses
Dynamic range is (a t,[link widoczny dla zalogowanych], f), the probability is 0.95,[link widoczny dla zalogowanych], the probability of falling outside this range is 1-0.95 = 0.05, due to the symmetry of the normal distribution (a f) I 1 I ( ) for a 0,025, Check the standard normal distribution table was 1.96; (2) by (1-, a solution f of soil was a soil of a? TESTING AND 00: Test data processing and error analysis of the first statistical about the basic concepts of probability 1.96 × 75-7O0 soil soil 147-553 ~ 847MPa that the reliability of the material fluctuations in the 95 range (553 ~ 847) MPa. 4.2 points Buweibuer Weibull distribution (WeibullDistribution) is the application of a wide range of distribution, especially in the fatigue strength and fatigue life of the study, occupies an extremely important position. (1) the characteristics of Weibull distribution described above normal although the very broad application, but it has an obvious drawback (lack of), that is, the smaller the better to make the failure probability. Then part of the strength (or life) to zero. This physical concept is not true cause of the lack of reason is the symmetry of normal distribution curve. Materials or parts of the strength (or life) there is always a limit, such as material fatigue limit of materials with cracks there is a fatigue crack growth below the threshold value of AK or the AK material will not fail, or that it's a zero probability of failure Therefore, from the physical concept, describes the probability distribution of these performance indicators should not be normal,[link widoczny dla zalogowanych], but should be skewed. One of the characteristics of Weibull distribution is that it fits this physical concept, it is the skewed distribution, when the strength (or life) is less than a certain value, the probability is zero in 1951 and 1952, published in the Weibull two articles, he considered the strength of the chain, which is a chain composed of a chain link. Set by the pull chain, the chain's weakest link in the intensity of the r, by deduction, by the following Weibull probability density function ... 』(a,) a lexp [a] (≥ r) UJ-I '. '. l0 ( 1 will come on behalf of the aging stage, in particular, m = 3 ~ 4, the curve becomes a normal distribution curve in Figure I-5 not the same Weibull distribution curves of the three fatigue life Weibull distribution, you often use the following formula, (Ⅳ = [] b - lexp [_ ((1-11) where N. - location parameter, the minimum life - scale parameter, characteristic life b - shape parameter Weibull slope or modulus type (BU 11) and type (1-10), as also the three-parameter Weibull distribution, but in certain conditions, such as electronic components in accelerated life testing, fatigue in the high stress (enhanced) test and other conditions, the three parameters of varying the second parameter Weibull degenerated into terror, (I t ~ - 'exp [_. Factory (Ⅳ)-bFN-~ -' exp [A (J (2) Probability of type (BU 10) and (1-11) points, we get the following expression for the cumulative probability of F0): 1 A exp [a! -:] 1 ... just a c. case of two-parameter Weibull distribution ,[link widoczny dla zalogowanych], then as long as equation (1-12) integral F () = 1 a exp [a (sound)] 1c Ⅳ: one. a c.,[link widoczny dla zalogowanych], sf \Weibull distribution parameters obtained can be through the formula (1-13) or type (1-14) by intensity or lifetime cumulative probability values. This is the introduction and examples in the future will be further instructions. * 43 *
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