Deep Drawing of Plain Weft-Knitted Fabric Composites: Part 1.: Cup Height Analysis

Abstract

Previous investigations on forming of plain weft-knitted fabric composite sheets show the ease of stretching due to fabric loop straightening. Pure dependence on stretching alone, however, sets the limit to which the shell height can be further increased. Recent deep drawn knitted fabric composites give greater cup height in comparison to stretch formed cup. In this paper a method of predicting the achievable cup height is proposed with due consideration to the fabric structure and tool dimensions. Comparison between the theoretical and experimental cup height shows good agreement.

Deep Drawing of Plain Weft-Knitted Fabric Composites Part 2.: Strain Field Analysis

“…Notwithstanding the above-mentioned discrepancies, there exists reasonable trends between the experimental and theoretical strain field although it is clear that the proposed model needs refining to take into account fibre bundle slippage and its extension. The present kinematic models, as well as recent proposals [11,13] provide an alternative to the kinetic models [9,10]. Development of kinetic models will complement the present kinematic models.…”

“…Plain weft-knitted Kevlar-49® reinforced polypropylene sheet specimens were prepared by the Film Stacking Method [13]. Grid radius ( r ) and height ( h ) of deep drawn specimens were measured using the “Pye-Unicam” 2-D travelling microscope and a “Mitutoyo” height gauge respectively.…”

“…Consider a circular sheet undergoing deep drawing as shown in Fig. 3, the mean ratio of meridional length after complete deformation to that before deformation is where l MACRO has been given earlier [13]. Previous experimental results [3,4] reveal that meridional elongation of a deep drawn plain weftknitted fabric composite is more uniformly distributed compared to those of homogeneous materials [1,2].…”

“…where λ MACRO has been given earlier [13]. Previous experimental results [3,4] reveal that meridional elongation of a deep drawn plain weft-knitted fabric composite is more uniformly distributed compared to those of homogeneous materials [1,2].…”