Research on processing methods of fatigue testing data reliability
Based on the basic principle of fatigue reliability,under the assumption of lognormal distribution of fatigue life,according to the t distribution theory,and in combination with the basic requirements of P-S-N curve for ships and marine engineering general components with 95％confidence and 97.72％reliability,the corresponding relationship between the number of fatigue specimens with 95％confidence and within 5％of the error limit and the allowable maximum variation coefficient value is calculated,The fatigue test of typical nodes is carried out based on this criterion as the minim-um number of test pieces in the group method fatigue test,and the Np with 95％confidence is obtained.The degree of linear correlation between fatigue stress logS and fatigue life logNp judged by the linear correlation coefficient r,and the fatigue life logNp and fatigue stress logS are linearly fitted by the least square method to obtain a P-S-N curve with 95％confidence,which is compared with the corresponding curve in the ⅡW,the results shows the method in this paper is feasibility and reli-ability.
number of test piecesP-S-N curvecoefficient of variationreliabilityconfidence
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