The Boeing Company
Method of forming a contoured hat stiffener

Abstract:

A flexible punch and die are used to form a flat composite laminate charge into a stiffener having a desired cross sectional shape. A desired contour is formed in the stiffener by bending the punch and die. Ply wrinkling is avoided during contouring by maintaining those portions of the stiffener subject to wrinkling in tension as the contouring is being performed. Bridging of the plies during the contouring process is avoided by first contouring those sections of the stiffener that are subject to wrinkling, and then contouring the remaining sections of the stiffener.