摘要
针对疲劳载荷造成的不同应力比和频率对船舶与海洋结构中裂纹扩展速率的影响,本文在分析了疲劳裂纹扩展速率几种经验公式的基础上,考虑了不同应力比与不同加载频率的疲劳载荷作用对直线裂纹和弯曲裂纹扩展速率的影响,提出了相应的计算公式;并与经验公式和现有实验数据进行了比较,验证了所提公式的正确性,研究结果可以直接应用于对不同频率、应力比条件下疲劳裂纹扩展速率的预测。结果表明:在同等应力强度因子变化幅值条件下,疲劳裂纹扩展速率随着疲劳载荷应力比和加载频率的增大而增大,在第一阶段增加比较缓慢、在第二和第三阶段增加非常迅速。本文给出的新型Irving公式适用于疲劳载荷作用下线弹性直线、弯曲裂纹扩展的第一、第二、第三阶段,计算结果比原Irving公式的结果更接近实验数据。该新型Irving公式更具有实用性和准确性。
In this article,corresponding computational formulas of fatigue crack propagation rate have been deduced on the basis of analyzing several empirical formula of fatigue crack propagation rate,considering the effect of fatigue load with diverse stress ratios and frequencies on straight and curve crack propagation rate.The correctness of new formulas have been validated,comparing with empirical formulas and existing experimental data,the results can be applied to forecasting crack propagation rate under fatigue loads with diverse stress ratios and frequencies.Under the condition of the same amplitude of varying stress intensity factor,fatigue crack propagation rate increases when stress ratio and frequency of fatigue loads increase,and it increases by inches in the first phase,very rapidly in the second and the third phases.There universally exist fatigue loads in shipping and ocean structures.Stress ratio and frequency of different fatigue loads are usually different,therefore it is very necessary to study the rule of the effect of different stress ratios and frequencies on structure crack propagation rate.The new Irving formulas provided by this article is applicable to the first,the second and the third phases of linear elasticity straight and curve crack propagation process under fatigue loads.The calculated results via the new Irving formulas are closer to experimental data than the originals.The new Irving formulas are more practicable and accurate than ever before.
出处
《应用力学学报》
CAS
CSCD
北大核心
2013年第3期356-360,474,共5页
Chinese Journal of Applied Mechanics
基金
河南省教育厅科学技术研究重点项目(2012B130007)
关键词
应力比
频率
扩展速率
直线裂纹
弯曲裂纹
stress ratio
frequency
propagation rate
linear crack
curve crack.
