荆洪阳 ,潘胜豪,徐连勇 ,赵 雷 ,韩永典
AuthorsHTML:荆洪阳 ^{1, 2}，潘胜豪 ^{1, 2}，徐连勇 ^{1, 2}，赵 雷 ^{1, 2}，韩永典 ^{1, 2}
AuthorsListE:Jing Hongyang,Pan Shenghao,Xu Lianyong,Zhao Lei,Han Yongdian
AuthorsHTMLE:Jing Hongyang^{1, 2}，Pan Shenghao^{1, 2}，Xu Lianyong^{1, 2}，Zhao Lei^{1, 2}，Han Yongdian^{1, 2}
Unit:1. 天津大学材料科学与工程学院，天津 300072；
2. 天津市现代连接技术重点实验室，天津 300072

Unit_EngLish:1. School of Materials Science and Engineering，Tianjin University，Tianjin 300072，China；
2. Tianjin Key Laboratory of Advanced Joining Technology，Tianjin 300072，China

Abstract_Chinese:研究了 Ti-6Al-4V(TC4)钛合金在不受轴向拉应力作用下的弯曲疲劳行为，设计了悬臂梁弯曲疲劳试验机对 TC4 钛合金进行弯曲疲劳试验，利用 ABAQUS 有限元模拟软件结合损伤模型模拟预测 TC4 钛合金的弯曲疲劳寿 命．通过对 TC4 钛合金进行 7 种不同弯曲疲劳幅值下的试验与模拟，研究了 TC4 钛合金在弯曲疲劳过程中的应力分 布与损伤断裂机理，利用扫描电子显微镜(SEM)分析了 TC4 钛合金的疲劳断口，研究了 TC4 钛合金在不同弯曲疲 劳幅值下的断裂方式．结果表明：弯曲疲劳数值计算寿命与试验结果处于 2 倍分散带内，计算断裂位置与试验断裂 位置均处于应力最大截面，偏离圆弧段中心截面 1 mm 处；弯曲疲劳裂纹萌生和扩展主要受应力控制，裂纹起源于 上下表面应力最大处，并逐渐向试样中心发展，直至试样断裂；当弯曲幅值较小时，弯曲疲劳试样的疲劳断口上存 在着大量的撕裂棱和二次裂纹，为明显的准解理断裂特征；当弯曲幅值进一步增大，材料内部变形提高，试样承受 应力增加，疲劳断口上存在着明显的韧窝，试验转变为韧性断裂．
Abstract_English:The bending fatigue behavior of Ti-6Al-4V(TC4)titanium alloy without the effect of axial tensile stress was studied. A cantilever bending fatigue testing machine was designed to perform a bending fatigue test on TC4 titanium alloy. The ABAQUS finite element simulation software combined with a damage model was employed to predict the life of TC4 bending fatigue. Through the test and simulation of seven different bending fatigue amplitudes of TC4 titanium alloy，the stress distribution and mechanism of the damage and fracture of TC4 titanium alloy during bending fatigue were studied. The fracture mode of TC4 titanium alloy under different bending fatigue amplitudes was analyzed by scanning electron microscopy(SEM). The results showed that the bending fatigue lives obtained by the nu\u0002merical simulation and test were within the double dispersion band. The fracture positions of the numerical simulation and test were located at the maximum stress section，1 mm away from the central section of the arc section. The ini\u0002tiation and propagation of bending fatigue cracks were mainly controlled by stress. The cracks originated from the maximum stress on the upper and lower surfaces and gradually developed toward the specimen center until the specimen broke. When the bending amplitude was small，a large number of tearing ridges and secondary cracks existed on the fatigue fracture of the specimen，which were quasi-cleavage fracture characteristics. When the bending amplitude was further increased，the internal deformation of the material was enhanced，the stress of the sample was increased，dimple characteristics occurred on the fatigue fracture，and the fracture mode changed to ductile fracture.
Keyword_Chinese:弯曲疲劳；有限元模拟；疲劳寿命预测；疲劳断口
Keywords_English:bending fatigue；finite element simulation；fatigue life prediction；fatigue fracture

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