45鋼的疲勞裂紋擴展速率及其工程構件的壽命預測

45鋼的疲勞裂紋擴展速率及其工程構件的壽命預測Fatigue Crack Growth Rate of 45 Steel and Fatigue Life Prediction of Its Engineering Components

在常溫下對調質態和正火態45鋼緊湊拉伸試樣進行了疲勞裂紋擴展速率試驗, 并根據Paris公式確定了兩種狀態試樣在穩定擴展階段的疲勞裂紋擴展速率; 分析了含缺陷的45鋼工程構件的張開型(I型)裂紋尖端的應力強度因子, 然后采用損傷容限設計原則, 根據斷裂力學試驗結果計算了構件的疲勞裂紋擴展壽命, 并進行了含缺陷45鋼構件的動態彎曲疲勞試驗, 以驗證理論推算的合理性。結果表明: 正火態45鋼的疲勞裂紋擴展速率略大于調質態45鋼的; 采用損傷容限設計原則估算的含缺陷45鋼構件的疲勞裂紋擴展壽命為2.3×106次,與動態彎曲疲勞試驗結果相吻合。

The fatigue crack growth rate (FCGR) test of 45 steel CT specimens (quenching and tempering condition and normalizing condition) was done at room temperature, and the FCGR equation in the stably expanding stage was determined by Paris formula. The stress intensity factor of open-type (type I) crack tip of 45 steel engineering components with defects was analyzed, and then according to the test results of FCGR and using the design method of damage tolerance, the fatigue lifetime for crack growth was calculated. At the same time, dynamic bending fatigue test on 45 steel components with defects was also done to validate the correctness of theoretical analysis. The results show that the FCGR of normalizing 45 steel was greater than that of quenching and tempering 45 steel. The calculated fatigue lifetime for crack growth of 45 steel components with defects by the design method of damage tolerance was 2.3×106 times, which agreed with the results of dynamic bending fatigue test.

全文下載：http://pan.baidu.com/s/1jIJTPGE