钢纤维自密实混凝土疲劳寿命预测不确定分析的证据理论方法

Uncertainty analysis in fatigue life prediction of self-compacting steel fiber reinforced concrete using evidence theory

针对钢纤维自密实混凝土疲劳寿命预测中存在诸如材料参数、试验数据、模型不确定等各种不确定性来源,造成疲劳寿命预测困难、预测不准确等问题,本文建立了基于S-N曲线的混凝土疲劳寿命预测不确定性模型,考虑模型参数的认知不确定性,提出了一种基于证据理论的混凝土疲劳寿命预测不确定性分析方法。选取0.5%钢纤维掺量的钢纤维自密实混凝土弯曲疲劳试验数据,采用证据理论和微分演化算法来完成各级应力水平下不确定性的量化和传播;通过与实际疲劳寿命和概率理论方法的预测结果进行比较分析,验证了该方法对钢纤维自密实混凝土疲劳寿命预测不确定性分析的有效性和可行性。

Fatigue life predictability of steel fiber-reinforced concrete(SCFRC)is difficult,making for inaccuracies in self-compacting.This is mainly caused by the existence of various material parameters and experimental data and model uncertainty.Therefore,in this paper,the uncertainty model of concrete fatigue life prediction based on the S-N curve was built,and a methodology based on evidence theory is presented for uncertainty analysis in fatigue life prediction of concrete,while considering the epistemic uncertainty of model parameters.Based on the experiment of SCFRC with a 0.5%steel fiber dosage,evidence theory and a differential evolution-based computational strategy were applied to quantify and propagate the epistemic uncertainty at all stress levels.Compared with the prediction results of actual fatigue life and probabilistic theoretical method,the efficiency and feasibility of the proposed approach were verified through a comparative analysis of probability theory.