Magnetic Repulsive Forces on ArmatureContacts

Transition to arcing contact in solid-armature railguns has been linked to several mechanisms. Recent work suggests magnetic blowoff forces arising from perimeter erosion as a possible significant mechanism. Three-dimensional finite-element (FE) models were constructed to analyze the repulsive contact forces resulting from perimeter erosion. Results show that magnetic blowoff occurs only when there is a loss of more than 98% of the contact area. Such gross perimeter erosion is unlikely and is not found in recovered armatures. Magnetic liftoff from perimeter erosion does not appear to be a causative mechanism in armature transition. This computational study also provided a platform for testing two FE codes, which showed very good agreement overall