%0 Journal Article
%T 锈蚀对钢材低周疲劳性能的影响分析
%A 宋方远
%A 谢旭
%J 浙江大学学报(工学版)
%D 2018
%R 10.3785/j.issn.1008-973X.2018.12.006
%X 以我国钢桥结构中使用较多的Q345钢材为例，对人工加速锈蚀试样进行2种应变幅下的低周疲劳试验研究.应用精细的有限元模型分析，基于微观断裂判据——循环空穴扩张模型（CVGM），对锈蚀钢材的低周疲劳断裂机理进行分析，讨论蚀坑对钢材低周疲劳（LDF）寿命的影响机理，并验证方法的有效性.结果表明，质量损失率约为6%的锈蚀Q345钢材试样的低周疲劳寿命比无锈蚀钢材减少约30%；完好试样与锈蚀试样的稳定滞回环形状几乎相同，锈蚀对钢材承载能力影响较小；在1%应变幅作用下，试样破坏现象为脆性的低周疲劳破坏，而在2.5%应变幅作用的循环荷载下，试样发生延性的超低周疲劳破坏.锈蚀引起钢材超低周疲劳寿命下降程度与蚀坑位置的应变集中有关，随着应变集中程度的增加，疲劳寿命的下降增大.</br>Abstract: The laboratory low cycle fatigue (LCF) tests of accelerated corrosion Q345 steel specimens under certain strain amplitudes were conducted. Based on finite element model (FEM) analysis and micromechanical fracture criteria cyclic void growth model (CVGM), the LCF fracture mechanism of the specimens was analyzed, and the influence mechanism of pitting corrosion on LCF life of the steel was discussed. Results show that the LCF life of corroded Q345 steel specimens with about 6% mass loss is reduced by approximately 30% in comparison with the intact ones; the shapes of stable hysteresis curves of intact specimens and corroded ones are found to be almost identical, and corrosion has little influence on the bearing capacity of steel. The fatigue test results show that specimens under 1% strain amplitude cyclic loading present brittle fracture, however, those under 2.5% strain amplitude present ductile fracture. This work indicates that LCF life reduction of corroded steel is mainly caused by strain concentration at the location of pitting corrosion, and the LCF life decreases with the increase of strain concentration degree.
%U http://www.zjujournals.com/eng/CN/10.3785/j.issn.1008-973X.2018.12.006