|
Fatigue In real engineering situations
materials experience fluctuating loads during use. The magnitude of the stress
fluctuation may be within the elastic range of the material, however, it
is found that material failure can occur through the process known as fatigue.
In the bicycle, two types of location are prone to fatigue failure: the
spokes that are always in tension and experience a fluctuating stress for each
revolution of the wheels, and the joints between frame members. |
|
|
|
|
The photographs show
a spoke that failed by fatigue. The nipple section (a) shows that the crack
started in the threaded region of the spoke. (b) shows the fracture surface,
the black arrow showing where the crack started and the top, matt grey section
being the final fast fracture region. |
|
|
|
|
|
|
|