Axisymmetric sheet forming of knitted fabric composite by combined stretchforming and deep drawing

Previous studies have demonstrated that sheet formability is governed by th e interlacing effect of pure stretch forming and pure deep drawing. In this paper, knitted fabric reinforced thermoplastic composite sheets, which exh ibit excellent stretchability and drapeability, are investigated for their formability. Initially a new parameter, X, which describes the amount of st retching relative to drawing during forming is introduced. It is shown that sheet forming processes, specified by the use of various combinations of f orming conditions, can be characterized by the parameter X. Finally, the ov erall formability of knitted fabric composite sheet is discussed with refer ence to the X-factor. (C) 1999 Elsevier Science Ltd. All rights reserved.