Fatigue failure of integral droppers of high-speed railway catenary under impact load

To explore the fatigue failure laws of dropper structures, this study performs impact fatigue tests and local simulation analyses on two newly proposed dropper structures. The failure modes of droppers having two different structures are examined, and the reasons for the differences between them discussed. During the crimping process, the large deformation of the tooth-shaped crimping dropper caused significant initial damage to the copper wire surface, significantly reducing the load-bearing capacity of the dropper. For the elliptical crimping dropper, the reduced size of the heart-shaped retaining ring resulted in a relatively high tensile stress along the edge of the dropper, resulting in crack initiation and structural fracture failure. Under the double logarithmic coordinates, linear relationships were observed between the impact load and life of both structural types of droppers. By performing fitting, the relationships between the impact load and life of the two types of droppers are determined.