A hole expansion process is an important process in producing a hub-hole in a wheel disc of a vehicle. In this process,
the main parameter is the formability of a material that is expressed as the hole expansion ratio. The hub-hole expansion
process is different from conventional forming processes or hole flanging processes from the view-point of its
deformation mode and forming of a thick plate. In the process, a crack is occurred in the upper edge of a hole as the hole
is expanded. Since prediction of the forming limit by hole expansion experiment needs tremendous time and effort, an
appropriate fracture criterion has to be developed for finite element analysis to define forming limit of the material.
In this paper, the hole expansion process of a hub-hole is studied by finite element analysis with ABAQUS/standard
considering several ductile fracture criteria. The fracture mode and hole expansion ratio is compared with respect to the
various fracture criteria. These criteria do not predict its fracture mode or hole expansion ratio adequately and show
deviation from experimental results of hole expansion. A modified ductile fracture criterion is newly proposed to consider
the deformation characteristics of a material accurately in a hole expansion process. A fracture propagation analysis at the
hub-hole edge is also performed for high accuracy of prediction using the new fracture criterion proposed.