Experimental study is performed on the probabilistic models for the long fatigue crack growth rates (da/dN) of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity f...Experimental study is performed on the probabilistic models for the long fatigue crack growth rates (da/dN) of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity factor range going down to the threshold and the average stress effect. The probabilistic models were presented on the equation. They consist of the probabilistic da/dN-ΔK relations, the confidence-based da/dN-ΔK relations, and the probabilistic- and confidence-based da/dN-ΔK relations. Efforts were made respectively to characterize the effects of probabilistic assessments due to the scattering regularity of test data, the number of sampling, and both of them. These relations can provide wide selections for practice. Analysis on the test data of LZ50 steel indicates that the present models are available and feasible.展开更多
Experimental study is performed on the probabilistic models for the long fatigue crack growth rates （da/dN） of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity...Experimental study is performed on the probabilistic models for the long fatigue crack growth rates （da/dN） of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity factor range going down to the threshold and the average stress effect. The probabilistic models were presented on the equation. They consist of the probabilistic da/dN-△K relations, the confidence-based da/dN-△K relations, and the probabilistic- and confidence-based da/dN-△K relations. Efforts were made respectively to characterize the effects of probabilistic assessments due to the scattering regularity of test data, the number of sampling, and both of them. These relations can provide wide selections for practice. Analysis on the test data of LZ50 steel indicates that the present models are available and feasible.展开更多
A simple probabilistic model for predicting crack growth behavior under random loading is presented. In the model, the parameters c and m in the Paris-Erdogan Equation are taken as random variables, and their stochast...A simple probabilistic model for predicting crack growth behavior under random loading is presented. In the model, the parameters c and m in the Paris-Erdogan Equation are taken as random variables, and their stochastic characteristic values are obtained through fatigue crack propagation tests on an offshore structural steel under constant amplitude loading. Furthermore, by using the Monte Carlo simulation technique, the fatigue crack propagation life to reach a given crack length is predicted. The tests are conducted to verify the applicability of the theoretical prediction of the fatigue crack propagation.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
基金Project supported by the National Natural Science Foundation of China (Nos.50375130and50323003), the Special Foundation of National Excellent Ph.D.Thesis (No.200234) and thePlanned Itemforthe Outstanding Young Teachers ofMinistry ofEducationofChina (No.2101)
文摘Experimental study is performed on the probabilistic models for the long fatigue crack growth rates (da/dN) of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity factor range going down to the threshold and the average stress effect. The probabilistic models were presented on the equation. They consist of the probabilistic da/dN-ΔK relations, the confidence-based da/dN-ΔK relations, and the probabilistic- and confidence-based da/dN-ΔK relations. Efforts were made respectively to characterize the effects of probabilistic assessments due to the scattering regularity of test data, the number of sampling, and both of them. These relations can provide wide selections for practice. Analysis on the test data of LZ50 steel indicates that the present models are available and feasible.
基金国家自然科学基金，Special Foundation of National Excellent Ph.D.Thesis，Outstanding Young Teachers of Ministry of Education of China
文摘Experimental study is performed on the probabilistic models for the long fatigue crack growth rates （da/dN） of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity factor range going down to the threshold and the average stress effect. The probabilistic models were presented on the equation. They consist of the probabilistic da/dN-△K relations, the confidence-based da/dN-△K relations, and the probabilistic- and confidence-based da/dN-△K relations. Efforts were made respectively to characterize the effects of probabilistic assessments due to the scattering regularity of test data, the number of sampling, and both of them. These relations can provide wide selections for practice. Analysis on the test data of LZ50 steel indicates that the present models are available and feasible.
文摘A simple probabilistic model for predicting crack growth behavior under random loading is presented. In the model, the parameters c and m in the Paris-Erdogan Equation are taken as random variables, and their stochastic characteristic values are obtained through fatigue crack propagation tests on an offshore structural steel under constant amplitude loading. Furthermore, by using the Monte Carlo simulation technique, the fatigue crack propagation life to reach a given crack length is predicted. The tests are conducted to verify the applicability of the theoretical prediction of the fatigue crack propagation.
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。
