7050铝合金锻件缺陷容限值试验方法研究

Test Methods for Determining Flaw Tolerance Value of 7050 Aluminum Alloy Forging

缺陷容限设计方法充分考虑直升机的特点,将损伤容限设计思想巧妙地应用于直升机的设计中,通过缺陷容限值保证关键动部件的服役安全。本文采用疲劳极限反推的方法测试了三种尺寸的缺陷容限门槛值,分别采用有限元法和Y.Murakami公式计算缺陷容限门槛值,结果表明:含有265μm,374μm,480μm缺陷尺寸的三种试件缺陷容限门槛值基本相同;缺陷容限门槛值明显低于长裂纹门槛值,采用长裂纹门槛值作为缺陷容限门槛值会导致偏于危险的结果;有限元法与Y.Murakami公式应力强度因子计算结果非常接近,Y.Murakami公式计算结果略低于有限元法。

Flaw tolerance design absorbs the characteristics of helicopter and is applied in the design of it. The methods to get the flaw tolerance value are not definite ; thus, this paper presented its testing methods. The values of three defects were tested by fatigue limit method and computed by finite element method and Y. Murakami function. The results show that the flaw tolerance values of three de- fects are essentially the same and lower than that of the threshold of long crack. That means it is relatively dangerous to use the value of threshold of long crack. The flaw tolerance values calculated by the two methods are similar, and the values computed by Y. Mu- rakami function are slightly lower than that by finite element method.