A damage process called fretting fatigue frequently occurs when two
surfaces are clamped together under a normal load with a small-scale
oscillatory motion due to cyclic loading. In contrast to the constant
contact loading, less attention has been paid to variable contact
loading which is going to be technically reviewed in this work. Emphasis
is put on the efforts made over the past decade and the future
challenges such as nonlinear effects of contact loads, friction,
frequency, slip amplitude and tribo-oxidation wear will be discussed.