裂纹深度和形状对构件断裂韧度的影响

在弯曲疲劳试验机上对几组包含有不同 a/ w值的贯穿裂纹和不同 a、c值的半椭圆裂纹的构件进行弯曲疲劳实验。结果表明 ,对于 60 Si2 Mn A钢来说 ,无论是表面裂纹还是贯穿裂纹 ,在浅裂纹情况下 ,其断裂韧度值比深裂纹高出 2 5%左右。当 a/ w值大于 0 .1时 ,无论 a/ w如何变化 ,KIC值基本保持不变。裂纹形状对断裂韧度的影响也不明显。

Effects of Crack Depth and Shape on Fracture Toughness

An experimental study discribed in this paper attempts to compare the behaviour of both through cracked specimens with different a/w ratios and surface cracked ones with different a and c values.Results show that the material 60Si2MnA steel is more resistant to crack growth. When the a/w ratios are less than 0.1,both shallow through and surface cracked specimens,give a toughness value which is about 25% higher than the deep cracked ones.For a/w larger than 0.1,the toughness K IC remains constant.Effect of crack shape on fracture toughness in negligible.