COLLAPSIBLE, COILED MANDREL

摘要

A collapsible, coiled mandrel, for use in co-curing of a hollow carbon-epoxy structure such as a stringer in aircraft construction, is made of a fiber stiffened with doping material that maintains an outer coil shape resistant to external compression forces when used as a mandrel during lay-up and curing, and is collapsible when an end of the fiber is pulled along its longitudinal axis so that it can be easily removed after curing and discarded. A method of fabricating a collapsible, coiled mandrel employs a mold with a shaped recess for forming a coil with a fiber wetted with a doping material fed in by an applicator, and rotating the applicator while backing it out to form the coil in the mold. In an alternative embodiment, a collapsible, coiled mandrel may be formed of a metal coil having a mandrel-shaped cross section and sleeved in a protective liner.

主权项

1. A collapsible, coiled mandrel for use in co-curing of a hollow carbon-epoxy structure comprising:
a fiber wetted by a doping material that provides the fiber with a property of stiffness when dried, said fiber being formed with coil turns extending along a longitudinal axis and maintaining an outer coil shape when dried that is resistant to external compression forces when used as a mandrel during a subsequent lay-up and curing of a hollow carbon-epoxy structure, said collapsible, coiled mandrel being collapsible axially by shear forces applied when an end of the fiber is pulled in a direction along the longitudinal axis so that the collapsible, coiled mandrel can be easily removed from the hollow carbon-epoxy structure after curing.