Upload
hoangcong
View
226
Download
0
Embed Size (px)
Citation preview
1
1Chapter 8 Failure
Ductile and brittle fracture
2Chapter 8 Failure
Moderately ductile fracture
100 mm
2
3Chapter 8 Failure
Brittle fracture
4Chapter 8 Failure
3 mm
4 mm160 mm
1 mm
Brittle fracture surfaces
4
7Chapter 8 Failure
Temperature effect on impact energy
Impa
ct E
nerg
y
Temperature
σ
Ductile-to-brittle
8Chapter 8 Failure
Cyclic loading
σmax
σmin
σ
time
σmS
5
9Chapter 8 Failure
Cyclic stress
uniaxial loading
torsional loading
flexural loading
10Chapter 8 Failure
Fatigue Design Parameters
Sfat
N = Cycles to failure103 105 107 109
S = stress amplitude
N = Cycles to failure103 105 107 109
S = stress amplitude
6
11Chapter 8 Failure
The S-N curveSt
ress
am
plitu
de, S
(MPa
)
Cycles to failure, N
12Chapter 8 Failure
crack origin
Fatigue Mechanism
8
15Chapter 8 Failure
Creep - temperature dependence
secondary
tertiary
16Chapter 8 Failure
Secondary Creep
10-2 10-1 1Steady state creep rate (%/1000hr)ε s
102040
100200 Stress (MPa)
427°C
538°C
649°C