78
Chapter 2
Figure 2.18 Inherent flaw in a large part.
Figure 2.19 Surface crack in a large part.
the inherent flaws [2.12] in steel, 2a length, under the surface run from 0.001
to 0.004 in. decreasing with strength. Aluminum and magnesium alloys vary
from 0.003-0.004 in. while copper alloy has, 2a crack length, of up to
0.007 in.
In [2.10] cracks are discussed as well as what K1c and Kth mean in
fatigue. When cracks grow [2.16] K~h is exceeded, and when cracks split
a part into pieces Krc has been exceeded.
-
--x l0 -4 <_ ath <_-- 1.8 X 10 -4
(2.70)
where E is the modulus and (7 is the highest stress. Work by Siebel and Gaier
presented by Forrest [2.12] on machining grooves will be compared with a~/,
in Table 2.8. An operating stress of 30 kpsi is selected for the illustration.
The representative rms values are from [2.30,2.62].
Chapter 2
Figure 2.18 Inherent flaw in a large part.
Figure 2.19 Surface crack in a large part.
the inherent flaws [2.12] in steel, 2a length, under the surface run from 0.001
to 0.004 in. decreasing with strength. Aluminum and magnesium alloys vary
from 0.003-0.004 in. while copper alloy has, 2a crack length, of up to
0.007 in.
In [2.10] cracks are discussed as well as what K1c and Kth mean in
fatigue. When cracks grow [2.16] K~h is exceeded, and when cracks split
a part into pieces Krc has been exceeded.
-
--x l0 -4 <_ ath <_-- 1.8 X 10 -4
(2.70)
where E is the modulus and (7 is the highest stress. Work by Siebel and Gaier
presented by Forrest [2.12] on machining grooves will be compared with a~/,
in Table 2.8. An operating stress of 30 kpsi is selected for the illustration.
The representative rms values are from [2.30,2.62].