摘要
为获得U75V钢轨材料的力学性能与疲劳性能,开展U75V钢轨材料的单调拉伸试验、高周疲劳试验与裂纹扩展试验。制作U75V钢轨材料标准试件,首先进行单调拉伸试验得到材料力学性能,并通过考虑延性损伤的弹塑性模型对钢轨材料断裂行为进行表征,识别U75V钢轨的力学材料参数;然后进行高周疲劳试验,利用最小二乘法拟合得到材料的高周疲劳S-N曲线;最后通过疲劳裂纹扩展试验得出U75V钢轨材料裂纹扩展速率的Paris公式参数。研究发现:U75V钢轨作为一种高强钢,其抗拉强度和屈服强度平均值分别能达到1 238、762 MPa,其应力应变曲线没有明显的屈服平台;材料在疲劳失效次数为500万次时的高周疲劳强度为518.0 MPa,约为抗拉强度的41.8%;由疲劳裂纹扩展试验拟合得到Paris公式为da/dN=1×10^(-16.978)(ΔK)^(4.515 4)。试验结果可为U75V钢轨在车轮滚动接触的力学行为研究提供材料参数。
In order to obtain the mechanical and fatigue properties of U75V rail material,monotonic tensile experiments and high cycle fatigue tests as well as crack propagation tests were conducted on U75V rail material.A batch of standard specimens of U75V rail material was made,and the mechanical properties of the material were first obtained through monotonic tensile testing.The fracture behavior of the rail material was characterized by an elastoplastic model considering ductile damage,and the mechanical material parameters of U75V rail were also identified.Then,based on the high cycle fatigue test,the S-N curve of the material′s high cycle fatigue was fitted using the least squares method.Finally,the Paris law parameters for the crack propagation rate of U75V rail material were obtained through fatigue crack propagation tests.Experiment results show that U75V rail,as a high-strength steel,can achieve tensile strength and yield strength of 1238 MPa and 762 MPa,respectively,and its stress-strain curve does not have a clear yield plateau.The high cycle fatigue strength of the material at 5 million fatigue failures is 518.0 MPa,which is approximately 41.8%of the tensile strength.The Paris formula obtained by fitting the fatigue crack propagation test is da/dN=1×10^(-16.978)(ΔK)^(4.5154).The experimental results are useful for studying the mechanical behavior of U75V rail under wheel rolling contact.
作者
刘守成
LIU Shoucheng(China Railway 11th Bureau Group Co.Ltd.,Wuhan Hubei 430064,China)
出处
《铁道建筑技术》
2025年第8期100-104,共5页
Railway Construction Technology
基金
湖北省重点研发计划项目(2023BCB047)
中国铁建股份有限公司B类课题(2023-B01)。
关键词
U75V钢轨材料
单调拉伸
高周疲劳
裂纹扩展
U75V rail material
monotonic tensile
high cycle fatigue
crack propagation
