30CrMnSiNi2A合金钢含损伤结构剩余疲劳寿命分散性及其影响因素试验研究

An Experimental Study of Dispersion of Residual Fatigue Life of Damage-Containing Structures of 30CrMnSiNi2A Alloy Steel and Its Influencing Factors

为挖掘含损伤结构满足高可靠度要求下的剩余疲劳寿命潜力,开展合金钢材料30CrMnSiNi2A含损伤结构剩余疲劳寿命测试试验,对剩余疲劳寿命分散性及其影响因素进行分析。通过含预裂损伤与预置线切割损伤试验件在等幅谱载荷作用下的疲劳对比预试验分析结果,简化正式试验流程。开展不同热处理工艺、不同载荷水平下含损伤结构剩余疲劳寿命定性分析试验。分析试验数据得出:通过热处理工艺提高合金钢材料强度极限,降低载荷水平,可有效提升含损伤结构剩余疲劳寿命;不同处理工艺及不同载荷水平条件下,随损伤尺寸的增加,剩余疲劳寿命分散系数差异增大;在较大损伤尺寸下,热处理后的含损伤结构试验件在低载荷水平下的剩余疲劳寿命分散性较低。降低热处理强化后的30CrMnSiNi2A合金钢含损伤结构载荷水平可有效提高满足可靠度要求的剩余疲劳安全寿命。

In order to explore the potential of residual fatigue life of damage-containing structures to meet the requirements of high reliability,the residual fatigue life test of damage-containing structures made of alloy steel material 30CrMnSiNi2A is carried out,and the residual fatigue life dispersion and its influencing factors are analyzed.The formal experiment procedures are simplified according to the results of fatigue comparison preliminary experiment test between pieces containing pre-cracked damage and pre-set wire-cut damage under equal amplitude spectral loading.The qualitative analysis of remaining fatigue life of damage-containing structures is performed under different heat treatment processes and different load levels.Test data analysis results show that the heat treatment process is able to improve the strength limit of alloy steel materials,reduce the load level,and effectively improve the remaining fatigue life of damage-containing structures.Under the conditions of different treatment processes and different load levels,with the increment of damage in size,the difference in the scattering factor of the remaining fatigue life increases.The damage being larger in size,the residual fatigue life of the heat-treated damage-containing structure test pieces under a low load level is lower,and the life dispersion is lower.By doing so,the remaining fatigue safety life can be effectively improved to meet the reliability requirements.