超静定桁架结构, 对数准则, 灰色预测模型, 威布尔分布, 疲劳寿命预测

A numerical method of fatigue life prediction of statically indeterminate truss structure based on gray model was established herein. This paper analyzed principles in dealing with the order of logarithm times, and determined right order of times to predict fatigue lifetime. Then it amended the definition of the critical parameters identifying failure elements, so that the choices of bounded parameters were more accurate. Before the search of main fatigue failure modes, this paper added the critical failure internal stress criterion, reducing the calculation of recognition algorithms for identifying failure modes. Based on the improved grey model(GM), it estimated the Weibull distribution function, and calculated different safe lifetimes of truss structure system under different reliability degrees. The numerical example of 10 truss structure shows the validity of the numerical method established. 

statically indeterminate truss structure, logarithm principle, grey model, Weibull distribution, fatigue life prediction