COMPARISON OF CONTINUOUS FIBER AND STRETCHBROKEN CARBON FIBER (SBCF) MATERIALS INFORMING PROCESSES

摘要

Newly developed Stretch Broken Carbon Fiber (SBCF) materials offer the potential to expand the range of feasible part shapes in automated diaphragm forming. Extensibility along the axis of reinforcement may decrease the levels of inter-ply and intra-ply shears required to allowrnthermoset prepreg systems to conform to complex shapes. In order to assess the formability ofrnwoven and unidirectional prepreg systems based on SBCF materials, a series of forming trialsrnwas conducted at Rensselaer Polytechnic Institute using a reconfigurable tool comprised of anrnarray of independently controllable pins. A range of part shapes, including, boxes, L –rnStiffeners, ellipsoids, C- channels and V-channels, was formed from both SBCF prepregs andrnequivalent continuous fiber materials. Preprinted orthogonal grid patterns were used to capturernsurface shear patterns, and these provided the principal bases for comparison of the respectiverndeformation modes. Results consistently showed that lower levels of shear were required in thernSBCF materials, though post-forming shape fidelity was superior. This suggests that, while dramatic differences in part quality were not noted, the SBCF materials provided a deformation mode that reduced the level of shear required. It is proposed that this deformation mode is stretching along the fiber axis.