摘要
目前有关临界距离法公式修正的相关研究较少,也未见此法在泵头体材料疲劳寿命研究中的报道。为了研究临界距离理论能否合理预测缺口试件的疲劳寿命,建立了某泵头体材料铬镍合金缺口试件的有限元模型,得到其缺口根部的线弹性应力场,通过光滑试样的疲劳拉压试验测定了此材料的S-N曲线,并进行了多组缺口试样的疲劳试验,得到其疲劳寿命,应用传统临界距离法中的点法和线法进行了缺口试样的理论疲劳寿命预估。研究结果表明:与试验结果对比发现传统点法和线法的误差分别为-35. 44%和140. 40%,这一结果相较于目前工程应用的其他方法较为精确,验证了临界距离法对缺口试件疲劳寿命预估的有效性。对传统点法和线法进行修正并用修正公式计算缺口试件的疲劳寿命,其与试验数据的误差分别为18. 87%和12. 44%。修正公式大大提高了疲劳寿命预估的精度,具有一定的实际意义。
To study whether the critical distance theory can reasonably predict the fatigue life of a notched specimen,the finite element model for the chrome-nickel alloy notched specimen of a certain pump head material was established,and the linear elastic stress field at the root of the notch was obtained.The S-N curve of the material was obtained by tensile and compression test.The fatigue life was obtained by fatigue test of multiple sets of notched specimens.The traditional fatigue distance method and line method were used to estimate the theoretical fatigue life of notched specimen.The study results show that the errors of traditional point method and line method are-35.44%and 140.40%,respectively,compared with the test results.The critical distance method accuracy is relatively high,which verifies the validity of the critical distance method for estimating fatigue life of notched specimens.The traditional point method and line method were modified and the modified formula was used to calculate the fatigue life of the notched specimen.The errors compared with the test data were 18.87%and 12.44%,respectively.The modified formula greatly improves the accuracy of fatigue life estimation and has great practical significance.
作者
王兆坤
周思柱
曾云
张思
Wang Zhaokun;Zhou Sizhu;Zeng Yun;Zhang Si(Strength and Vibration of Mechanical Structures Research Institute,Yangtze University)
出处
《石油机械》
北大核心
2020年第3期113-120,共8页
China Petroleum Machinery
基金
国家科技重大专项“易损件寿命预估方法研究”(2016ZX05038-001-LH002)
国家自然科学基金项目“非常规压裂泵头体裂纹扩展规律研究”(51674040)。
关键词
临界距离理论
疲劳寿命
泵头体
缺口试件
线弹性应力场
修正公式
theory of critical distance
fatigue life
pump head
notched specimen
linear elastic stress field
modified formula
