Corrosion Speeds Damage - Flash FLASHV1 User Manual

Fatigue is the term used to describe accumulated damage to
a part caused by repeated loading. To cause fatigue dam
age, the load the part receives must be great enough. A
crude, often-used example is bending a paper clip back and
forth (repeated loading) until it breaks. This simple definition
will help you understand that fatigue has nothing to do with
time or age. A bicycle in a garage does not fatigue. Fatigue
happens only through use.
So what kind of "damage" are we talking about? On a micro
scopic level, a crack forms in a highly stressed area. As the
load is repeatedly applied, the crack grows. At some point
the crack becomes visible to the naked eye. Eventually it
becomes so large that the part is too weak to carry the load
that it could carry without the crack. At that point there can
be a complete and immediate failure of the part.
One can design a part that is so strong that fatigue life is \\
nearly infinite. This requires a lot of material and a lot of
weight. Any structure that must be light and strong will have
a finite fatigue life. Aircraft, race cars, motorcycles all have
parts with finite fatigue lives. If you wanted a bicycle with an
infinite fatigue life, it would weigh far more than any bicycle
sold today. So we all make a tradeoff: the wonderful, light
weight performance we want requires that we inspect the
structure.
What to look for
• ONCE A CRACKS STARTS IT CAN GROW AND GROW
FAST. Think about the crack as forming a pathway to
failure. This means that any crack is potentially danger-
ous and will only become more dangerous.
SIMPLE RULE 1 : If you find crack, replace the part.
• CORROSION SPEEDS DAMAGE. Cracks grow more
quickly when they are in a corrosive environment. Think
about the corrosive solution as further weakening
and extending the crack.
SIMPLE RULE 2 : Clean your bike, lubricate your bike,
protect your bike from salt, remove any salt
as soon as you can
• STAINS AND DISCOLORATION CAN OCCUR NEAR
A CRACK. Such staining may be a warning sign that a
crack exists.
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