Abstract: The traditional parametric method is difficult to adapt to variable structure design,
presented a new parametric method in varied structure designing which named as AFV
(Abstract-Fuse-Verification) technology. First, the component are abstracted into different parts,
forming template library; then each part can be designed separately and any combination of parts is
supported, improving the ability to adapt to the design of variable structures; the dimension of each
part are verified finally in accordance with the relevant standards, avoiding illegal topological
variation. In addition, AFV technology support the plug-in switching CAD platforms. The railway
vehicle axle plug-in based on UG platform being developed using AFV technology, shows the
feasibility of this tech.

Key words: AFV, variable structure, UG, parametric design, axle