A method of constant △K value is applied experimentally to investigatechemical short crack characteristics of GC-4 high-strength steel in 3.5%NaClsolution. Experimental results show that there is a critical point of ...A method of constant △K value is applied experimentally to investigatechemical short crack characteristics of GC-4 high-strength steel in 3.5%NaClsolution. Experimental results show that there is a critical point of crack geometry aon da / dN-a curve of the crack propagation at constant △K value. When the cracklength a < a , chemical short crack effect appears. The value of a is almost not af-fected by the loading frequency, stress ratio and △K level. The ratio of characteristiccrack propagation rate of chemical short cracks to that of long cracks is a weak func-tion of the loading frequency, stress ratio and △K level. Based on the analysis, the rela-tion between the short crack propagation rate and crack size is suggested.展开更多
The effects of environmental media,both in atmosphere and in 3.5% NaCl aqueous solution, on the growth of short cracks in comparison with the long ones have been investigated under fatigue loading on the specimens of ...The effects of environmental media,both in atmosphere and in 3.5% NaCl aqueous solution, on the growth of short cracks in comparison with the long ones have been investigated under fatigue loading on the specimens of single-edge crack about 0.05—0.15 mm for A537CLI steel.The growth rate of short cracks is faster than those of long ones around the threshoht stress intensity.The threshold stress intensity for short crack growth decreases with de- creasing crack length.The acceleration effect of the salt water,as compared with atmosphere environment,on the growth of short cracks under fatigue is much greater than that on the growth of long cracks.展开更多
为了对裂纹疲劳寿命进行快速准确预测,针对常用的疲劳实验和数值仿真实验中各自存在的实验条件受限、计算步骤繁琐、计算过程耗时较长等问题,以大型桥梁钢桁架中的裂纹为研究对象,提出一种结合裂纹分析软件FRANC3D和长短期记忆(long sho...为了对裂纹疲劳寿命进行快速准确预测,针对常用的疲劳实验和数值仿真实验中各自存在的实验条件受限、计算步骤繁琐、计算过程耗时较长等问题,以大型桥梁钢桁架中的裂纹为研究对象,提出一种结合裂纹分析软件FRANC3D和长短期记忆(long short term memory,简称LSTM)网络模型的裂纹疲劳寿命预测方法。首先,建立钢桁架的有限元模型,通过裂纹分析软件FRANC3D进行疲劳裂纹扩展分析并建立相关数据集;其次,通过疲劳裂纹的扩展仿真数据关注裂纹的扩展状况,收集裂纹特征信息对裂纹疲劳寿命进行预测。实验结果表明,所提出的方法具有较高的预测准确性,同时极大地提升了训练速度,可为裂纹疲劳寿命预测提供参考。展开更多
文摘A method of constant △K value is applied experimentally to investigatechemical short crack characteristics of GC-4 high-strength steel in 3.5%NaClsolution. Experimental results show that there is a critical point of crack geometry aon da / dN-a curve of the crack propagation at constant △K value. When the cracklength a < a , chemical short crack effect appears. The value of a is almost not af-fected by the loading frequency, stress ratio and △K level. The ratio of characteristiccrack propagation rate of chemical short cracks to that of long cracks is a weak func-tion of the loading frequency, stress ratio and △K level. Based on the analysis, the rela-tion between the short crack propagation rate and crack size is suggested.
文摘The effects of environmental media,both in atmosphere and in 3.5% NaCl aqueous solution, on the growth of short cracks in comparison with the long ones have been investigated under fatigue loading on the specimens of single-edge crack about 0.05—0.15 mm for A537CLI steel.The growth rate of short cracks is faster than those of long ones around the threshoht stress intensity.The threshold stress intensity for short crack growth decreases with de- creasing crack length.The acceleration effect of the salt water,as compared with atmosphere environment,on the growth of short cracks under fatigue is much greater than that on the growth of long cracks.
文摘为了对裂纹疲劳寿命进行快速准确预测,针对常用的疲劳实验和数值仿真实验中各自存在的实验条件受限、计算步骤繁琐、计算过程耗时较长等问题,以大型桥梁钢桁架中的裂纹为研究对象,提出一种结合裂纹分析软件FRANC3D和长短期记忆(long short term memory,简称LSTM)网络模型的裂纹疲劳寿命预测方法。首先,建立钢桁架的有限元模型,通过裂纹分析软件FRANC3D进行疲劳裂纹扩展分析并建立相关数据集;其次,通过疲劳裂纹的扩展仿真数据关注裂纹的扩展状况,收集裂纹特征信息对裂纹疲劳寿命进行预测。实验结果表明,所提出的方法具有较高的预测准确性,同时极大地提升了训练速度,可为裂纹疲劳寿命预测提供参考。
