Because of the importance of lightweight constructions, nowadays other materials are more
and more substituting components which had previously been made of metals. The usage of
short fiber-reinforced plastics instead of metals seems self-evident in many cases because
of their high specific strength and the favorable manufacturing processes. For fatigue
life prediction a simulation process was established, which takes into account the fiber
orientation and distribution as a result of an injection molding simulation. Hypotheses
for fatigue life prediction of orthotropic materials have been derived from a lot of tests
on specimens, implemented in the standard fatigue software tool FEMFAT and verified so far
with component tests.