Mechanical performance and modelling of a fully recycled modified CF/PP composite

Abstract

A fully recycled carbon fiber reinforced maleic anhydride grafted polypropylene (MAPP)-modified polypropylene (rCF/ rPP) composite material has been developed and characterized. This new composite was manufactured employing papermaking principles, dispersing the recycled carbon fibers (rCF) in water, and forming them into mats. Two layers of the recycled polypropylene (rPP) films manufactured using press-forming were sandwiched between three rCF preform layers in a stack. The stack was heated and press-formed resulting in a composite plate with a nominal thickness of 1.20 mm and a fiber volume fraction of 40%. A series of tensile tests using rectangular specimens cut in four different directions (0 , 90 , AE 45 ) in the composite plate were performed to confirm in-plane material isotropy. Models to predict stiffness and strength of the short fiber rCF/rPP composite were also employed and validated using experiments. The models were found to be in good agreement with experimental results. Fiber length distribution measurements were performed before (unprocessed) and after (processed) composite manufacturing to investigate the influence of processing on fiber degradation. The results revealed a significant reduction in fiber length by the press-forming operation. To model the viscoelastic and viscoplastic responses of the composite an inelastic material model was employed and characterized using a series of creep and recovery tests. From the creep tests, it was found that the time and stress dependence of viscoplastic strains follows a power law. The viscoelastic response of the composite was found to be linear in the investigated stress range. The material model was validated in constant stress rate tensile tests and the agreement was good, even close to the rupture stress.

Thermo-elastic behaviour of carbon-fiber reinforced polymer and the effect of adding nanoparticles at elevated heat intensity

“…The comparative plots are provided in Figure 9 below. The plots demonstrate good correlation with about 5% error when compared to the results obtained by Szpieg et al [27]. Therefore, the modelling approach Figure 8.…”

“…Findings based on the FEA study conducted suggest that CFRP composite material offers good resistance to thermal stress, even at elevated temperatures up to 800 K. The results were compared with Al-Qrimli et al [28] and Szpieg et al [27], and a good correlation was observed. However, it is recommended to conduct experiments to further validate the numerical results.…”

“…The stress-strain relationship obtained from the numerical results were compared with those obtained by AL-Qrimli et al [28] and Szpieg et al [27]. AL-Qrimli et al [28] studied the thermal-mechanical behaviour of carbon reinforced composite in typical fire conditions, while Szpieg et al [27] performed similar study with carbon fiber reinforced maleic anhydride grafted polypropylene (MAPP) composite material. The comparative plots are provided in Figure 9 below.…”

“…To quantify the ability of the composite to absorb and conduct the thermal load is the main objective of this study in addition to assessing the residual stresses in the composite due to thermal loading. A finite element model is developed for this purpose, which is validated with experimental results by Szpieg et al [27] and Al-Qrimli et al [28].…”

Deep drawing of organic sheets made of hybrid recycled carbon and thermoplastic polyamide 6 staple fiber yarns

“…Thermoplastic rCF compounds for injection molding (Connor 6 and Kreibe 22 ) and compression molding of semifinished products, such as rCF BMC and sheet molding compound (SMC) (e.g. Allen, 8 Turner et al, 9,14 Pickering et al, 12 Szpieg et al 23 ), were thoroughly researched. The first SMC parts made of rCF are already in application, for example, in the BMW 7 series.…”