Bending properties of carbon/glass and carbon/aramid fabric composites with various stacking structures by the VARTM method

Abstract

In this paper, the bending properties of woven carbon/glass and carbon/aramid fabric-reinforced polymer laminates is studied using a combination of experimental analysis and fracture observation. Six types of each hybrid composite were manufactured by lamination of the carbon/aramid fabric and carbon/glass fabric using VARTM. Bending behaviors were fundamentally evaluated for the six types of monolithic composites laminated by the same fabric. The objective was to achieve a good bending strength by effective combination of composite structures using limited amounts of a raw material. It was shown that the bending property was different, depending on the type of fiber, lamination structure, and the number of layers.

Flexural properties of notched carbon–aramid hybrid composite laminates

“…At a certain stress value, i , a stress drop occurs due to fiber breakage in the upper carbon fiber layer and delaminations at the interface between carbon and aramid layers. [29][30][31][32][33] These delaminations grow at carbon/aramid fiber interface due to the large difference in the interlaminar shear properties of both fiber types. After this stage, the stress slightly increases again by increasing the applied displacement, which means that the specimen can sustain more stress before complete failure.…”

“…This can be attributed to the presence of aramid layers inside this laminate, which absorbs more applied energy without transferring this energy to the carbon layers at the lower part. 29 As a result, the carbon layers in the lower part of the laminate can sustain more bending stresses before failure (before reaching the flexural strength of the laminate, F ). Hence, since there is transition stage between the damage initiation and complete failure, the damage in laminate SL follows a progressive process which is not catastrophic.…”

“…[33][34][35][36] During such a loading case, higher shear stresses in the upper quarter of the laminate due to compression on this part cause matrix cracking and fiber breakage of the carbon fibers. 29,30,34 Since, the fibers are hybridized in an intra-ply manner, the breakage of carbon fibers should be followed by breakage in aramid fibers. Therefore, the upper quarter of the laminate cannot withstand more loads, which reduces the ability of the laminate to sustain load.…”

“…In the laminate IL, each ply of the laminate was made of carbon and aramid fibers. Based on the conclusions presented by Song, 29 which highlighted that the sandwich hybridization methodology presents larger flexural strength of carbon-aramid hybrid laminates with equal carbon to aramid fiber content, the current sandwich hybrid laminate was designed to have the ratio of carbon to aramid fibers equals 1:2, while this ratio equals 1:1 for IL. These ratios result in lower unit weight and unit cost of SL than IL due to the lower density and price of aramid fibers than carbon fibers.…”

Performance of hybrid Innegra-carbon fiber composites

“…Also, carbon-outside/glass-inside clustered hybrid configuration gave lower notch sensitivity compared to other hybrid configurations. Song 15 investigated bending behavior of carbon/glass and carbon/aramid hybrid composites. Swolfs et al 16 studied the bonding in intralayer carbon fiber/self-reinforced polypropylene hybrid composites for different levels of weak and strong bonding.…”