摘要
对紧凑拉伸试样进行有限元分析,考察止裂孔边缘的应力分布情况,对比不同状况下裂纹尖端的力学特性,研究了孔径及附加孔对止裂效果的影响.结合钢桥面板局部模型实验,对开裂试件打孔止裂后进行疲劳实验,通过比较不同试件的疲劳寿命,对有限元分析结果进行了验证.分析和实验结果表明,经过止裂孔钻孔处理后,应力集中点位于试样预制裂纹直线延伸方向与止裂孔孔边缘相交处,相对于未打孔,裂纹尖端应力显著下降.裂纹尖端打孔止裂,能够提高构件疲劳寿命,且孔径越大,止裂效果越明显,孔径8mm以后,增大孔径所产生的止裂效果逐渐降低.不同孔径钻孔处理的疲劳试件,各阶段裂纹再次扩展速率相当,属于裂纹中速率扩展区,附加孔并没有影响裂纹扩展速率,但使疲劳寿命显著地提高.
Based on the finite element model analysis of compact tension samples, the effect of stop hole with different diameter and additional hole was researched, and the stress distribution along the stop hole edge and mechanical properties of the crack tip under different conditions were considered. By comparing residual fatigue life of each local sample of steel bridge deck, the finite element model analysis results were verified. The analysis and experiments results show that, stress concentration point locates at the intersection of crack propagating direction and the stop hole edge. Comparing to undrilled-hole samples, crack tip stress decreases significantly. Residual fatigue life of samples is increased by drilling hole at crack tip. The larger the diameter, the better is the crack arrest effect. The benefit of enlarging diameter of stop hole gradually decreases, when diameter is larger than 8mm and then increases. The crack growth rate of each fatigue sample is nearly equal in both stages, which is located in mid- rate propagation area. The additional hole does not influence crack growth rate, but effectively increases residual fatigue life of samples.
出处
《河南大学学报（自然科学版）》
CAS
2016年第6期732-738,共7页
Journal of Henan University:Natural Science
基金
国家自然科学面上基金项目(51478163)
江苏省交通科学研究计划项目(2013Y10-1
2014Y02)
关键词
钢桥面板
疲劳
止裂孔
应力集中
裂纹扩展
steel bridge deck
fatigue
stop hole
stress concentration
crack propagation
