Optimization of the formability of knitted fabric composite sheet by meansof combined deep drawing and stretch forming

The formability of sheet metals has been investigated widely in the last 5 decades. However, formability studies on polymer composite materials are ve ry limited and relatively new. This paper describes the sheet formability o f knitted Kevlar fiber reinforced polypropylene composite material. Previou s studies have indicated that sheet formability is governed by the complex interplay between pure stretch forming and pure deep drawing. For this purp ose, a new parameter, X, which describes the amount of stretching relative to drawing during forming has been introduced. The formability characterist ics of knitted fabric composite are discussed with reference to X. The effe cts of forming conditions (such as blank-holding load, the blank size and t he tool geometry) on the composite formability are also described. (C) 1999 Elsevier Science S.A. All rights reserved.