摘要
基于高周疲劳弯曲实验,研究了航空用铝合金板材Al7475-T3的各向异性疲劳行为.结果表明:轧制后形成了扁平长条状结构的7475-T3铝合金具有良好的耐疲劳损伤性能.在室温弯曲加载条件下,从3个平面(S-T,S-L,T-L)截取的光滑试样的疲劳极限最高可达200 MPa,除在T-L面上表现为各向同性外,其余两面的疲劳性能均表现出各向异性.采用以最弱链接理论为基础的概率疲劳准则,分析了铝合金板材中疲劳裂纹产生的可能性,但模拟结果与实际相差较远.综合考虑晶粒有效滑移长度和夹杂物尺寸两因素,对疲劳极限的影响进行模型计算,得出的Kitagawa曲线与实际情况比较吻合.
The anisotropic fatigue behavior of aircraft aluminum alloy plate was investigated by using bending fatigue test.The results show that after the rolling process,Al7475-T3 forms a pancake structure and the resistance to fatigue damage has been improved.The specimens taken from the 3 plans（S-T,S-L,T-L） show the highest fatigue strength reaches 200 MPa in the room temperature bending fatigue test,except the performance of plan T-L is isotropic,the other two plans S-T and S-L both show us anisotropic.Based on the weakest link theory,using the probabilistic fatigue criterion,the simulation of the anisotropic fatigue is applied to analyze the possibility of the nucleation of microcracks in the aluminum plate,but the result of the simulation is far from that of the actual situation.Taking into consideration of both the effective slip length of grains and the size of inclusions which affect the fatigue strength in the model,the Kitagawa curve is in good agreement with the actual situation.
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2011年第11期1678-1683,共6页
Journal of Shanghai Jiaotong University
