摘要
在多级加载疲劳试验中 ,加载历史对疲劳寿命的影响很大 ,特别是当低 -高顺序加载时 ,损伤演变速度减缓 ,剩余寿命远较损伤力学方法估算的大 ,有时甚至出现受损试样的剩余寿命远大于原始材料的情况。本文运用非线性动力学观点 ,根据二级加载的非线性疲劳寿命公式 ,用计算机做模拟试验 ,发现会出现分岔现象。结合疲劳损伤中“锻炼”效应的微观机理 ,认为材料疲劳损伤演化过程中非线性特征是产生这种现象的原因。通过大量试验和实践经验而得到的现有的疲劳损伤公式 ,可以较好地反映客观实际情况。研究它们之间各个参变量与疲劳损伤的关系 ,能够发现材料在疲劳损伤过程的分岔和混沌现象。
It is very important to predict service life wit h interaction effect under fatigue loading. For example, when the loading order is from low to high, the damage evolution for two or multi-level fatigue may de celerate the damage rate. The remaining life under two or multi-level fatigue i s more than that expected by the damage theory, sometimes it is even much more t han the whole life in the original material. In this paper, with the advanced no nlinear dynamics, according to the two or multi-level formula in the fatigue da mage theory, an experiment is performed by computer simulation, and the bifurcat ion phenomena is discovered in the results. Furthermore, with the coaxing effect s, this phenomenon can be explained as a nonlinear property in the procedure of fatigue damage evolution. In fact, those formulas in the fatigue damage theories were formulized on the basis of many experiments, so they can be applied to eng ineering problem accurately. To study them, the bifurcation phenomenon and chaot ic motion may also be found in the procedure of fatigue damage.
出处
《机械科学与技术》
EI
CSCD
北大核心
2001年第6期894-896,共3页
Mechanical Science and Technology for Aerospace Engineering
基金
国家自然基金资助项目 ( 196 72 0 5 1)
