The Boeing Company
Constrained Creep Forming of Contoured Composite Stiffeners

Abstract:

A composite laminate stiffener is formed to contour with reduced ply wrinkling using constrained creep forming. The tooling apparatus is provided with flexible cauls which constrain the stiffener during the contour forming process. The creep forming is carried out at a slow enough rate so that friction or shear resistance between the resin and fibers of the plies remains low enough that slippage can occur and significant compression stresses are not generated rate, allowing relaxation of residual stresses in the stiffener.