Effects of Cure Pressure on Resin Flow, Voids, and Mechanical Properties

Abstract

The effects of cure pressure on resin flow, compaction, void content, and mechanical properties of fiber reinforced composites were investigated. Tests were performed on lami nates made of Fiberite T300/976 and T300/934 unidirectional prepreg tape. Data are pre sented on compaction, resin flow, and void content which lend support to the validity of the Springer-Loos model. Data are also given showing the effects of cure pressure on void content and on the compressive strength and short-beam shear strength and modulus.

High-resolution computed tomography in resin infused woven carbon fibre composites with voids

“…Page 12 As also shown in Fig. 6, the size of the detectable individual voids in this volume exhibits a range of several orders of magnitude, from 10 to 1,000 µm 3 . This distribution suggests a "bell-curve" number distribution of void sizes, i.e.…”

“…2) Voids accumulate around both the layer interfaces and yarns and are nearly completely absent from the layer thickness between those interfaces and away from yarns. 3) Void distribution follows the orientation of fibres in adjacent layers, suggesting that out-of-plane flow is a significant mechanism in void formation and mobility. 4) Observations 1-3 above all imply that current void formation and mobility models must be expanded from a microscale approach to the laminate scale, in order to focus on out-of-plane bubble movement and yarn bubble entrapment.…”

“…However, RTM results in more voids in the laminate due to entrapment of air bubbles during filling [1,2]. Voids are known to be detrimental to the mechanical performance of the material [3][4][5][6][7][8][9][10]. A deeper understanding of the formation of voids, and their effect on damage and mechanical performance is desirable in the context of improving the performance of RTM and other non-autoclave manufactured components.…”

“…Previous work has investigated the influence of voids on mechanical properties [3][4][5][6][7][8][9][10], most having focused on prepreg materials. As the microstructure and constituents in composites manufactured with resin infusion processes are usually different from those in autoclave-cured prepregs, the effects of defects on mechanical properties must still be established in RTM composites to pave the way for determining design allowables for the void contents.…”

“…This is a single parameter, which is of limited use in determining local microstructural effects. Unlike prepreg processing [3][4][5][6][7], void concentrations are not M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT Page 4 homogeneous in resin infusion processes such as RTM due to the pressure gradient resulting from infusion and the often more heterogeneous microstructure of the fibre preforms. The voids are also not homogeneous in size and shape due to the variety of bubble entrapment mechanisms governing void formation [11].…”