摘要
在反复循环荷载作用下构件或材料易出现疲劳损伤,导致结构出现突发性疲劳脆性破坏,故需对构件或材料的疲劳损伤进行精确评价,避免灾害性事故发生。但现有的疲劳损伤评价模型为了简化分析,常忽略了荷载顺序和相互作用等效应,使得疲劳损伤分析精度不足,为此,需对构件或材料的疲劳损伤模型进行改进,使其能够精确评价疲劳损伤。基于叶笃毅提出的疲劳损伤模型,推导材料的多级疲劳损伤模型。在此基础上,通过提出对数应力平方比的幂函数等效形式来考虑荷载相互作用效应,并应用所提等效规则,结合叶笃毅多幅级疲劳模型,推导多级载荷作用下非线性疲劳损伤累积改进模型,使疲劳模型能够考虑多级荷载的顺序和相互作用效应。基于所提改进模型建立材料疲劳极限状态方程,应用概率密度演化方法对极限状态方程进行求解,并建立求解过程,分析得到材料非线性时变疲劳可靠度。最后采用材料疲劳试验对所提模型在疲劳寿命预测和可靠度分析中的准确性进行验证。研究结果表明:所建立的模型疲劳寿命预测误差最小可达1%,可靠度分析精度提高30%,表明模型具有更高精度,能够应用于工程实际。
Components or materials are prone to fatigue damage under repeated cyclic loads, resulting in sudden fatigue and brittle failure of the structure. Therefore, it is necessary to accurately evaluate the fatigue damage of components or materials to avoid catastrophic accidents. However, in order to simplify the analysis, the existing fatigue damage evaluation models often ignore the effects of load sequence and interaction, which makes the accuracy of fatigue damage analysis insufficient. Therefore, it is necessary to improve the fatigue damage model of components or materials to accurately evaluate the fatigue damage. Based on the fatigue damage model proposed by Ye Duyi, the multi-level fatigue damage model of materials was derived. On this basis, the load interaction effect was considered by the power function equivalent form of logarithmic stress square ratio. A nonlinear fatigue damage cumulative improvement model under multi-level loads was derived by applying the proposed equivalent rules and combined with Ye Duyi’s multi-level fatigue model, so that the fatigue model can consider the sequence and interaction effects of multi-level loads. Then, the fatigue limit state function of materials was constructed by the proposed model, and the state function was solved by the probability density evolution method for obtaining the nonlinear time-dependent fatigue reliability of materials. Finally, the materials fatigue tests were used to verify the accuracy of the proposed model in fatigue life prediction and reliability analysis. The results show that the fatigue life prediction error of the proposed model can be as small as 1%, and the accuracy of reliability analysis is increased by 30%, which indicates that the proposed model has higher accuracy and can be applied to engineering practice.
作者
高凯
高鑫
GAO Kai;GAO Xin(Chongqing Yufu Urban Construction Operation&Developemnt Co.,Ltd.,Chongqing 401121,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China;Guizhou Province Quality and Safety Traffic Engineering Monitoring and Inspection Center Co.,Ltd.,Guiyang 550000,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2022年第3期807-813,共7页
Journal of Railway Science and Engineering
基金
重庆市研究生科研创新项目(CYB20027)。
关键词
非线性疲劳损伤模型
韧性耗散
荷载相互效应
概率密度演化
可靠度
nonlinear fatigue damage model
static toughness exhaustion
load interaction effect
probability density evolution method
reliability
作者简介
通信作者:高凯(1988-),男,四川南充人,博士,从事结构健康监测、结构可靠度研究,E-mail:kgao928@163.com。
