Abstract:A gear of an aerial system broke during the unfolding test. A series of test results show that the metallurgical
structure, the chemical composition, and the mechanical properties of the material all meet the demands of related
standards. Via scanning electron microscope, the micro appearance of the fracture has been observed. Evident
fatigue strips were found in the crack characters. Combined with test process of the aerial system, it is concluded that
the failure mechanism is that the fatigue broken of individual teeth caused the plastic overload fracture of other teeth
and finally lead to the failure of the whole link connection.
