%A WANG Tianshuai, HE Xiaofan, WANG Jinyu, LI Yuhai %T Estimation method for DFR value of DED-TA15 titanium alloy based on bimodal lognormal distribution %0 Journal Article %D 2022 %J Acta Aeronautica et Astronautica Sinica %R 10.7527/S1000-6893.2021.25013 %P 225013-225013 %V 43 %N 3 %U {https://hkxb.buaa.edu.cn/CN/abstract/article_18500.shtml} %8 2022-03-15 %X Fatigue strength evaluation of Additive Manufacturing (AM) metal materials is a prerequisite for the application of AM materials to the main bearing structure of aircraft.Taking DED-TA15 titanium alloy as the research object, we conduct a fatigue test of standard cylindrical specimens at three stress levels and obtain the fatigue life data.A bimodal lognormal distribution model is built to describe the fatigue life distribution of DED-TA15 titanium alloy based on the test results.The EM algorithm is used to establish the parameter estimation method of the bimodal lognormal distribution, and the Bootstrap method is adopted to calculate the fatigue life with the specified confidence level and reliability requirements.Compared with the traditional lognormal distribution model, the bimodal lognormal distribution can describe the fatigue life of DED-TA15 titanium alloy more accurately.The fatigue life at the high reliability and high confidence level, as well as the Detail Fatigue Rating (DFR) value, is improved.This method reduces the excessive limitation of allowable design stress and effectively increases the load potential of DED-TA15 titanium alloy.