摘要
采用有限元程序计算TC21钛合金圆形缺口试样不同载荷下缺口根部的应力分布,以及循环载荷下缺口根部的循环应力比的变化。结果表明,缺口根部的轴向应力集中因子Kσ和应变集中因子Kε与载荷大小有关,但变化趋势不同。缺口根部区处于三向应力状态,尽管三向应力的最大值的位置随载荷变化而变化,但等效应力最大值在表面。根部位置切向应力与轴向应力的比值随着载荷的变化而变化。由于缺口根部的塑性变形,随载荷升高,缺口根部的应力比降低,当名义应力超过1100MPa时,应力比反而增加。在疲劳过程中,高循环应力时,缺口根部的应力比也有一定变化。
The stress distribution at the notch root of round notched fatigue specimens of TC21 alloy under monotonic loading and cyclic loading was calculated by adopting FEM. The results indicate that the axial stress concentration factor Kσ and strain concentration factor Kε are related to the magnitude of cyclic stresses, but the variation trends are different. The notch root region is in three-dimensional stress state, and the position of the maximum yon raises equivalent stress is at the surface of the notch root, though the positions of the maximum values of three directional stresses change with the cyclic stress. Furthermore, the ratio between the tangent stress and the axial stress at the notch root changes due to the variation of the cyclic stresses. Because of the plastic deformation at the notch root, the cyclic stress ratio decreases with the increase of nominal cyclic stress, but when the cyclic stress is higher than 1100 MPa, the cyclic stress ratio increase with the increase of cyclic stress. During the fatigue process, the cyclic stress ratio slightly alters when the cyclic stress is high enough.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2007年第12期2084-2088,共5页
Rare Metal Materials and Engineering
