拉扭复合加载下相位差对2A12-T4铝合金高周疲劳失效的影响  

Effect of Phase Angle on High-cycle Fatigue Failure of 2A12-T4 Aluminum Alloy under Tension-torsion Non-proportional Loading

作　　者：时新红[1] 张建宇[1] 鲍蕊[1] 费斌军[1] 

机构地区：[1]北京航空航天大学固体力学研究所,北京100191

出　　处：《航空材料学报》2010年第5期93-96,共4页Journal of Aeronautical Materials

摘　　要：采用航空工业常用材料2A12-T4铝合金,针对不同应力幅比,进行了拉扭复合加载下相位差对多轴高周疲劳失效的影响试验,研究了恒定应力幅比λ=1下相位差对多轴疲劳失效的影响,对不同应力幅比下疲劳寿命随着相位差的变化进行了对比,并分析了λ=1时不同相位差下试样的断裂形式。结果表明,在相同的Von-Mises等效应力下,当应力幅比λ=1时,随着相位差的增大,疲劳寿命逐渐升高,且与相位差的正弦近似成指数关系。在不同应力幅比下随着相位差的增大,疲劳寿命均呈现升高的趋势,但只有λ=1的情况对疲劳寿命的影响最大。试件断裂呈现Ⅰ型与Ⅱ型的混合型破坏特征,随着相位差的增大,试件断裂由Ⅰ型裂纹占主导逐渐过渡到Ⅱ型裂纹占主导。Fatigue experiments were carried out to investigate the effect of phase angle on multi-axial high-cycle fatigue failure of 2A12-T4 aluminum alloy under tension-torsion non-proportional loading.The change of fatigue life with phase angle under different ratio of stress amplitude was discussed.The failure mode of specimen was studied under different phase angle when τa/σa=1based on macro-analysis of fracture.The results showed that when ratio of stress amplitude τa/σa=1,fatigue life raised gradually with the increasing of phase angle and had an exponential relation with the sin of phase angle under the same Von-Mises equivalent stress.When phase angle increased,fatigue life raised under different ratio of stress amplitude and the change was more obvious when τa/σa=1 than others.By analysis,fracture presented a mixed mode of modelⅠand modelⅡ.The dominant mode had a transition from modelⅠto modelⅡwhen phase angle increased.

关 键 词：多轴疲劳 高周疲劳 疲劳寿命 非比例加载 相位差 

分 类 号：O346.2[理学—固体力学]