Fatigue property assessment of parallel wire stay cable I: fatigue life model for wire
Lan Chengming1 Xu Yang2 Ren Denglu1 Li Na3 Liu Zhiqiang3
1. National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083, China
2. Harbin Institute of Technology, Harbin 150090, China
3. CCCC Highway Consultants Co., Ltd., Beijing 100088, China
Abstract：As the first part with respect to the fatigue property assessment of the parallel wire stay cable, a fatigue life model of the steel wire is established. The three-parameter power function is employed to describe the fatigue stress-life model, and the two-parameter Weibull distribution is used to represent the fatigue life of steel wire under the specified stress range. Supposed that the fatigue life of individual wire calculated by the two models are equivalent under the specified stress range with the identical survival probability, a novel multi-parameter Weibull model for the fatigue life assessment of steel wire is deduced, in which fatigue life and stress range are compatible. On the basis of conditional probability distribution of the censored data, an improved expectation maximization (EM) algorithm is employed to estimate the parameters of the proposed model. The fatigue data of the strands from the literature are analyzed to illustrate the fitness and characteristics of the proposed model. Finally, the fatigue life model for the steel wire is established based on the fatigue data obtained by fatigue experiment. The results indicate that the proposed fatigue life model can fit the fatigue data of strands and steel wires better. For the specified stress range, the probability distribution of the fatigue life is simplified as a two-parameter Weibull model. For the specified fatigue life, the probability distribution of the corresponding stress range is simplified as a three-parameter Weibull model. It is convenient to deal with the censored data with the proposed EM algorithm. The whole fatigue data are pooled together to estimate the parameters of the proposed fatigue life model, thus the accuracy of the parameter estimation can be improved.
兰成明 徐阳 任登路 李娜 刘志强. 平行钢丝斜拉索疲劳性能评定I：钢丝疲劳寿命模型[J]. 土木工程学报, 2017, 50(6): 62-70.
Lan Chengming Xu Yang Ren Denglu Li Na Liu Zhiqiang. Fatigue property assessment of parallel wire stay cable I: fatigue life model for wire. 土木工程学报, 2017, 50(6): 62-70.
