Cold expansion technology has been one of the most common anti-fatigue strengthening
technologies for
fastening holes. In this paper,
a newly developed assisting sleeve is employed to install the
ForceMate
bushing, and the resulting deformation, rebound, drawing force, contact
pressure, residual stress and damage are compared to those resulting
from traditional ForceMate bushing process. The 3D Hashin failure criterion
was implemented into finite element simulation via a specially
written user subroutine to simulate the deformation and failure of
cold expanded composite holes. The results show that a more uniform
distribution of residual contact pressure and residual circumferential
stress is achieved by introducing the assisting sleeve, and less
damage around the composite hole is induced under the same interference
level.
In comparison with
the traditional ForceMate bushing process, a better
anti-fatigue performance of cold expanded composite holes can be expected
by using the assisting sleeve.